JP4791137B2 - Position specifying device, image reproducing device, position specifying method, and position specifying program - Google Patents

Description

  The embodiment according to the present invention relates to radar image processing for calculating a correct position of a target from data of the target observed by a SAR (Synthetic Aperture Radar).

Conventionally, for example, when considering a marine vessel, matching between a wake (wake) and a marine vessel has been made in order to know the true position of the vessel.
JP-A-2005-214755

  The moving target in the SAR image shifts in the azimuth direction depending on the range speed of the target. Therefore, there is a problem that the position of the moving target in the SAR image is shifted from the position of the true target. Further, the conventional method of matching a wake and a ship has a problem that it does not function when there are a ship with a small number of wakes and a plurality of ships.

  The embodiment of the present invention has been made to solve the above-described problem, and specifies the correct position of a target that has shifted in the azimuth direction depending on the range-direction speed of the target. Objective.

A position specifying device according to an embodiment of the present invention is a position specifying device that specifies the position of a target observed by a SAR.
A speed measurement unit that measures a range direction speed, which is a moving speed of the target in the range direction, by a processing device and stores it in a storage device, and a shift amount in the azimuth direction based on the range direction speed measured by the speed measurement unit. Is calculated by the processing device and stored in the storage device, a SAR reproduction image input unit that inputs the SAR reproduction image observed by the SAR by the input device, and the shift amount calculated by the shift amount calculation unit And a position specifying unit for specifying the position of the target by the processing device based on the coordinates of the target of the SAR playback image input by the SAR playback image input unit and storing the target in a storage device.

Further, the shift amount calculation unit of the position specifying device according to the embodiment of the present invention calculates the shift amount by Δx = (v _r / V _P ) · _RC . Here, [Delta] x, the amount of shift in the azimuth direction, _{v r,} the speed of the range direction, _{V P,} the speed of the SAR, _{R c} is the distance between the SAR and the target in the synthetic aperture center.

  Furthermore, the speed measurement unit of the position specifying device according to the embodiment of the present invention includes a data input unit that inputs range-compressed data obtained by performing range compression on the target data observed by the SAR, and a range direction. A speed input unit that inputs a plurality of predicted movement speeds having a predicted speed and a predicted speed in the azimuth direction by an input device, each predicted movement speed of the plurality of predicted movement speeds input by the speed input unit, A reference function generation unit that generates a plurality of reference functions by a processing device based on the distance information between the SAR and the target based on the movement information and the predicted movement information of the target, and stores the reference function in the storage device; Based on the reference functions of the plurality of reference functions generated by the unit, the data after the range compression input by the data input unit is azimuth-compressed to obtain a plurality of data after the azimuth compression. An azimuth compression processing unit that is generated by a processing device and stored in a storage device, and a processing device calculates the sharpness of an image indicated by each post-azimuth compression data of the plurality of azimuth compression data generated by the azimuth compression processing unit. When the reference function used to generate the azimuth-compressed data having the highest sharpness calculated by the sharpness calculation unit to be stored in the storage device and the prediction function input to the distance relation information is generated. A speed determining unit that determines that the moving speed is the moving speed of the target by the processing device and stores it in the storage device, and a speed that extracts the range direction speed from the moving speed determined by the speed determining unit and stores it in the storage device And an extraction unit.

  Furthermore, the speed measuring unit of the position specifying device according to the embodiment of the present invention is characterized in that the speed in the range direction is measured by a speed designation method ISAR (Inverse Synthetic Aperture Radar).

  In addition, the speed measuring unit of the position specifying device according to the embodiment of the present invention is based on the acquired range migration curve and the range migration curve obtained when the target is not moving in the range direction of the target. A movement straight line calculation unit that calculates a straight line indicating the movement of the movement and stores it in the storage device, and a speed calculation unit that calculates the range direction speed based on the straight line calculated by the movement straight line calculation unit and stores it in the storage device. It is characterized by that.

An image reproduction apparatus according to an embodiment of the present invention is an image reproduction apparatus that reproduces an image observed by SAR.
Based on the speed measurement unit that measures the range direction speed, which is the moving speed of the target in the range direction, by the processing device based on the speed designation method ISAR and stores it in the storage device, and the range direction speed measured by the speed measurement unit, The shift amount calculation unit that calculates the shift amount in the azimuth direction by the processing device and stores the shift amount in the storage device, the SAR reproduction image input unit that inputs the SAR reproduction image observed by the SAR, and the shift amount calculation unit calculated Based on the shift amount and the coordinates of the target of the SAR playback image input by the SAR playback image input unit, the position specifying unit for specifying the position of the target by the processing device and storing it in the storage device, and the speed specifying method ISAR A position correcting unit that generates a corrected image obtained by correcting the target of the generated image by the processing device to the position specified by the position specifying unit and stores the corrected image in the storage device , Characterized in that it comprises an image reproducing section for reproducing the image after correction in which the position correction unit is generated.

In addition, the position specifying device according to the embodiment of the present invention is a position specifying device that specifies the positions of a plurality of targets observed by the SAR.
A speed measuring unit that measures the moving speed of each target in the range direction of a plurality of targets by a processing device and stores the speed in a storage device, and the moving speed of each target of the plurality of targets measured by the speed measuring unit Based on the above, a shift amount calculation unit for calculating a shift amount of each target in the azimuth direction of the target by the processing device and storing the shift amount in the storage device, and a SAR reproduction image observed by the SAR are input by the input device. Based on the SAR reproduction image input unit, the shift amount of each target of the plurality of targets calculated by the shift amount calculation unit, and the coordinates of the target of the SAR reproduction image input by the SAR reproduction image input unit, And a position specifying unit that specifies the position of each target of the target by a processing device and stores the target in a storage device.

A position specifying method according to an embodiment of the present invention is a position specifying method of a position specifying device for specifying a position of a target observed by a SAR.
Based on the speed measurement step in which the speed measurement unit measures the speed in the range direction that is the moving speed of the target in the range direction by the processing device and stores it in the storage device, and the range direction speed measured in the speed measurement step, the azimuth direction The shift amount calculating step in which the shift amount calculating unit calculates the shift amount to the storage device and storing it in the storage device, and the SAR reproduced image input unit inputs the SAR reproduced image observed by the SAR with the input device. Based on the input step, the shift amount calculated in the shift amount calculating step, and the coordinates of the target of the SAR reproduction image input in the SAR reproduction image input step, the position specifying unit specifies the position of the target by the processing device. And a position specifying step for storing in a storage device.

A position specifying program according to an embodiment of the present invention is a position specifying program of a position specifying device for specifying the position of a target observed by a SAR.
Based on the speed measurement step in which the speed measurement unit measures the speed in the range direction that is the moving speed of the target in the range direction by the processing device and stores it in the storage device, and the range direction speed measured in the speed measurement step, the azimuth direction The shift amount calculating step in which the shift amount calculating unit calculates the shift amount to the storage device and storing it in the storage device, and the SAR reproduced image input unit inputs the SAR reproduced image observed by the SAR with the input device. Based on the input step, the shift amount calculated in the shift amount calculating step, and the coordinates of the target of the SAR reproduction image input in the SAR reproduction image input step, the position specifying unit specifies the position of the target by the processing device. The computer is caused to execute a position specifying step stored in a storage device.

  According to the position specifying device according to the embodiment of the present invention, the speed measuring unit that measures the range direction speed that is the moving speed of the target in the range direction, and the shift amount calculating unit that calculates the shift amount in the azimuth direction. It is possible to obtain the amount of shift of the target in the azimuth direction. Therefore, according to the position specifying device according to the embodiment of the present invention, it is possible to specify the correct position of the target that has shifted in the azimuth direction depending on the speed in the range direction of the target.

  First, an example of a hardware configuration of the image sharpening device 100 according to the embodiment will be described with reference to FIGS. 1 and 2.

FIG. 1 is a diagram illustrating an example of an appearance of an image sharpening device 100 according to an embodiment.
In FIG. 1, an image sharpening device 100 includes a CRT (Cathode Ray Tube) display device 901, a keyboard (K / B) 902, a mouse 903, a compact disc device (CDD) 905, a database 908, a system unit 909, and a server 910. These are connected by cables.
Further, the image sharpening apparatus 100 is connected to the Internet 940 via a local area network (LAN) 942 and a gateway 941.
Here, the CRT display device 901 is an example of the display device 984.

FIG. 2 is a diagram illustrating an example of a hardware configuration of the image sharpening device 100 according to the embodiment.
In FIG. 2, the image sharpening apparatus 100 includes a CPU (Central Processing Unit) 911 that executes a program. The CPU 911 is connected to a ROM 913, a RAM 914, a communication board 915, a CRT display device 901, a K / B 902, a mouse 903, an FDD (Flexible Disk) 904, a CDD 905, and a magnetic disk device 920 via a bus 912. The CPU is an example of a processing device.
The RAM 914 is an example of a volatile memory. The ROM 913 and the magnetic disk device 920 are examples of a nonvolatile memory. These are examples of the storage device 982.
The communication board 915 is connected to the LAN 942 or the like.
Further, the K / B 902, the mouse 903, and the like are examples of the input device 980.
The CPU 911 is an example of a processing device.

Here, the communication board 915 is not limited to the LAN 942 but may be directly connected to the Internet 940 or a WAN (Wide Area Network) such as ISDN. When directly connected to the Internet 940 or a WAN such as ISDN, the image sharpening apparatus 100 is connected to the Internet 940 or a WAN such as ISDN, and the gateway 941 is unnecessary.
The magnetic disk device 920 stores an operating system (OS) 921, a window system 922, a program group 923, and a file group 924. The program group 923 is executed by the CPU 911, the OS 921, and the window system 922.

The program group 923 stores programs that execute functions described as “˜units” in the description of the embodiments described below. The program is read and executed by the CPU 911.
In the file group 924, what is described as “to determination” in the description of the embodiment described below is stored as “to file”.
Also, the arrows in the flowcharts described in the following description of the embodiments mainly indicate data input / output, and the data for the data input / output is the magnetic disk device 920, FD, optical disk, CD, MD. (Mini disc), DVD (Digital Versatile Disk) and other recording media. Alternatively, it is transmitted through a signal line or other transmission medium.

  In addition, what is described as “unit” in the description of the embodiment described below may be realized by firmware stored in the ROM 913. Alternatively, it may be implemented by software alone, hardware alone, a combination of software and hardware, or a combination of firmware.

  In addition, a program that implements the embodiment described below may be stored using a recording device using another recording medium such as the magnetic disk device 920, FD, optical disk, CD, MD, DVD, or the like.

  1 and 2 are also examples of the appearance and hardware configuration of the speed measurement device and the image definition determination device, respectively.

Embodiment 1 FIG.
Next, the first embodiment will be described. In the first embodiment, the image sharpening device 100 and the image sharpening method that can correctly sharpen an image of a target even when there is a radio wave scatterer in the surroundings, or when the brightness of a moving target is weak. The image sharpening program will be described. The processing that the image sharpening apparatus 100, the image sharpening method, and the image sharpening program have is called a speed designation method ISAR.

  First, the sharpening of the target by the isolated scattering point method ISAR will be described based on FIG. 3 and FIG. 4, and then the sharpening of the target by the speed designation method ISAR will be described based on FIG. 5 and FIG.

FIG. 3 is a diagram illustrating the sharpening of the target by the isolated scattering point method ISAR when there is only one moving target. When data after range compression with only one moving target is input and processed by the isolated scattering point method ISAR, the isolated scattering point can be normally tracked because the brightness of only the target is strong. Succeeded in sharpening the target. That is, in this case, according to the isolated scattering point method ISAR, the target is reproduced more clearly than a normal SAR image.
FIG. 4 is a diagram illustrating the sharpening of a target by the isolated scattering point method ISAR when there is a moving target and a clutter that has a different speed from the target and has high luminance. When range-compressed data is input that includes a moving target and a clutter that has a different speed from the target and has a strong luminance, and is processed by the isolated scattering point method ISAR, it is focused on the clutter that has a higher luminance than the target. Therefore, the target is further blurred. That is, in this case, according to the isolated scattering point method ISAR, the target is reproduced in a blurred manner as compared with a normal SAR image.
Therefore, in the isolated scattering point method ISAR, the target cannot be clearly reproduced if different speed clutters are included in the image.

FIG. 5 is a diagram illustrating the sharpening of a target by the speed designation method ISAR when only one moving target exists. When range-compressed data having only one moving target is input and processed by the speed designation method ISAR, the target is successfully clarified when the speed of the target is input. That is, in this case, according to the speed designation method ISAR, the target is reproduced more clearly than a normal SAR image.
FIG. 6 is a diagram illustrating the sharpening of the target by the speed designation method ISAR when there is a moving target and a clutter having a different speed from the target and having a high luminance. If you input the data after range compression in which there is a moving target and a clutter that has a different speed from the target and has strong brightness, and processed by the speed specification method ISAR, the target will be Clutters that are sharpened and have different speeds are blurred. Here, when the moving speed of the clutter is the same as that of the target, the target is sharpened and the clutter is also sharpened by processing by the speed designation method ISAR.
Therefore, in the speed designation system ISAR, the target can be reproduced clearly even if different speed clutters are included in the image.

  Next, the relative motion between the SAR and the target, which is the basis of the speed designation method ISAR, will be described.

  First, based on FIG. 7, FIG. 8, the relative motion of SAR and a stationary body (target which does not move) is demonstrated. FIG. 7 is a diagram showing a relative relationship (distance) between the SAR and the stationary body after t seconds. FIG. 8 is a diagram illustrating movement of the stationary body in FIG. 7 due to rotation. That is, the stationary body itself does not move, but the stationary body moves by rotation when viewed from the SAR. That is, here, the stationary body is affected by the rotation. Here, the motion of a stationary body existing on the rotating coordinates is defined, and the Doppler frequency in that case is derived.

  7 and 8, the following equation is obtained as the relative motion (distance) between the SAR and the stationary body after t seconds.

さらに、

further,

式２を、マクローリン展開を用いて、式３のように二次の項まで展開する。

Equation 2 is expanded to the second order term using Equation (3) using Macrolin expansion.

式３を用いて、式４のようにドップラ周波数ｆ_ｄを表現できる。

Using Equation 3, the Doppler frequency f _d can be expressed as in Equation 4.

Next, based on FIGS. 9 and 10, the relative motion between the radar and the moving body (moving target), which is the basis of the speed designation method ISAR, will be described. FIG. 9 is a diagram showing a relative relationship (distance) between the SAR and the moving body after t seconds. FIG. 10 is a diagram illustrating movement of the moving body in FIG. Here, as described above, it is assumed that the moving body is affected by rotation. Here, the movement of the moving body in the azimuth direction and the range direction is defined, and the Doppler frequency f _d in that case is derived.

  9 and 10, the following equation is obtained as the relative motion (distance) between the SAR and the moving body after t seconds. Here, it is assumed that the target moves in a constant velocity linear motion for a predetermined period.

さらに、

further,

式６を、マクローリン展開を用いて、式７のように二次の項まで展開する。

Expression 6 is expanded to the second-order term as shown in Expression 7 by using Maclaurin expansion.

式７を用いて、式８のようにドップラ周波数ｆ_ｄを表現できる。

Using Equation 7, the Doppler frequency f _d can be expressed as in Equation 8.

ここで、

here,

である。

It is.

Next, the reference function E _ref for azimuth compression considering the movement of the target can be obtained from the Doppler _center frequency f _dcE obtained by the above equation 8 and the Doppler frequency change rate β _P as follows. it can.

Here, in the speed designation method ISAR, the predicted speed in the range direction of the target and the predicted speed in the azimuth direction are input as v _A and v _R to the reference function E _ref 10 to perform azimuth compression. While confirming blurring of the image after azimuth compression, the process is repeated a plurality of times to output the most tightened (clear) image. Thereby, in the speed designation method ISAR, a clear image of the moving target is obtained. Here, even if there is a clutter having a different speed, the image is sharpened based on the designated predicted speed, so that it is not affected by the clutter.

Further, the synthetic aperture time _{T A_isar} used for ISAR becomes less synthetic aperture time _{T A} normal SAR. In addition, the higher the sway of the target, the higher the resolution can be obtained with a shorter synthetic aperture time. Furthermore, by shortening the synthetic opening time T A — _isar , it is possible to consider that the target is moving at a constant linear velocity. Therefore, here, the start time α _start of the synthetic opening time T A — _isar and the synthetic opening time T _An end time α _{end of A_isar} can be arbitrarily selected. For example, the following more optional end time alpha _{end The} synthetic aperture time to normalize _{T A} 1, start time alpha _start and synthetic aperture time _{T A_isar} synthetic aperture time _{T A_isar} used for ISAR for SAR as Equation 11 It can be so. The synthetic opening time T A — _isar is, for example, 2 seconds when the SAR synthetic opening time T _A is 5 seconds and the start time α _start is 1.5 seconds and the end time α _end is 3.5 seconds. It is. This normalizes the synthetic aperture time _{T A} for SAR in Equation 11 by 1, the start time alpha _start 0.3, an end time alpha _{end The} select 0.7, and cut out 2 seconds.

In addition, the range migration correction according to the speed in the range direction of the target is also performed each time the azimuth is compressed, thereby achieving high resolution. The correction amount _Cr is obtained from Equation 12 shown below, and the locus of the target is shifted by one line so that the locus of the target becomes a straight line in the azimuth direction. The correction amount _Cr is usually obtained as a real number, and the integer part thereof corresponds to a pixel level shift amount in the range direction. The decimal part corresponds to a shift amount of 1 pixel or less in the range direction, and is interpolated by a third-order convolution interpolation method or a polyphase filter.

  Next, functions of the image sharpening device 100 according to the first embodiment will be described with reference to FIG. FIG. 11 is a functional block diagram illustrating functions of the image sharpening device 100 according to the first embodiment.

  The image sharpening device 100 sharpens the image of the target from the data of the target observed by the SAR. Here, the image sharpening device 100 sharpens the image of the target from the data of the target observed by the SAR, for example, by the speed designation method ISAR. The image sharpening device 100 includes an input unit 110, a processing unit 130, a storage unit 160, a display unit 170, an input device 980, a storage device 982, and a display device 984.

The input unit 110 includes a data input unit 112, a reference function information input unit 114, an accompanying information input unit 120, and a definition determination input unit 122.
The data input unit 112 uses the input device 980 to input range-compressed data obtained by performing range compression on the target data observed by the SAR. Here, the data after range compression refers to an image having a high resolution only in the range direction in which the pulse compression processing is performed in the range direction.
The reference function information input unit 114 includes a speed input unit 116 and a synthetic aperture time information input unit 118. The speed input unit 116 inputs a predicted moving speed, which is a predicted speed at which the target moves, from the input device 980. Here, the predicted moving speed has a predicted speed v _{R in} the range direction and a predicted speed v _{A in the} azimuth direction. The synthetic opening time information input unit 118 inputs synthetic opening time information having a synthetic opening time start time α _start and a synthetic opening time end time α _end by the input device 980.
Accompanying information input unit 120 inputs the input device 980 image accompanying information accompanying the predicted velocity v _A non-image prediction velocity v _R and the azimuth direction in the range direction, such as the speed of the position and SAR of SAR.
The sharpness determination input unit 122 uses the input device 980 to input a determination as to whether post-IFFT data displayed by the data display unit 172 described later is clear.

The processing unit 130 includes a range migration correction unit 132, a zero padding processing unit 134, an FFT processing unit 136, an azimuth compression processing unit 138, an IFFT processing unit 140, and a reference function generation unit 142.
Range migration correction unit 132 calculates the correction amount C _r in accordance with the range direction velocity v _R of the target, based on the calculated correction amount C _r, the range for the data after range compression the data input unit 112 inputs Migration correction is performed and corrected data is generated. Here, the range migration correction unit 132 calculates the correction amount C _r in accordance with the predicted velocity v _R of the input range direction, perform range migration correction.
The zero padding processing unit 134 generates zero padded data in which the number of pixels of the corrected data is a power of two by padding the corrected data generated by the range migration correcting unit 132 with 0. In order to perform fast Fourier transform (FFT), the number of pixels must be a power of two. Therefore, the zero padding processing unit 134, for example, as shown in Expression 13 below, the number N of pixels in the azimuth direction for the fast Fourier transform, which is the smallest power of 2 larger than the number of pixels in the cut out azimuth direction. _Fft is calculated, and 0 (zero) is filled by the number of pixels N _{zero_pad} that is zero-padded, which is the number of pixels that is insufficient for the number, as shown in Equation 14 below.

ＦＦＴ処理部１３６は、ゼロ詰め処理部１３４が生成したゼロ詰めデータをアジマスラインごとに複素高速フーリエ変換し周波数領域に変換したＦＦＴ後データを処理装置により生成する。さらに、ＦＦＴ処理部１３６は、後述する参照関数生成部１４２が生成した参照関数をＦＦＴしＦＦＴ後参照関数を処理装置により生成する。
アジマス圧縮処理部１３８は、後述する参照関数生成部１４２が生成した参照関数に基づき、データ入力部１１２が入力したレンジ圧縮後データをアジマス圧縮しアジマス圧縮後データを処理装置により生成する。ここでは、アジマス圧縮処理部１３８は、ＦＦＴ後参照関数に基づき、ＦＦＴ後データをアジマス圧縮する。アジマス圧縮処理部１３８は、例えば、切り出された画像の１アジマスラインとアジマス圧縮用の参照関数について、周波数領域で掛け合わせることで、アジマス圧縮（相関処理）を行う。これにより、時間領域におけるアジマス方向への高分解能化を図る。
ＩＦＦＴ処理部１４０は、アジマス圧縮処理部１３８がアジマス圧縮したアジマス圧縮後データを逆高速フーリエ変換（ＩＦＦＴ）し、ＩＦＦＴ後データを処理装置により生成する。ＩＦＦＴ処理部１４０は、周波数領域でアジマス圧縮処理されたデータについて、ＩＦＦＴを行うことで、ＩＳＡＲ処理画像を生成する。
参照関数生成部１４２は、ＳＡＲの移動情報と目標物の予測移動情報とに基づいたＳＡＲと目標物との距離関係情報に基づき参照関数を処理装置により生成して記憶装置９８２に記憶する。参照関数生成部１４２は、例えば、上記式１０の参照関数Ｅ_ｒｅｆを生成する。予測移動情報とは、速度入力部１１６が入力した予測移動速度である。例えば、上記式１０はレンジドップラー再生方式を対象に生成しているが、再生方式はこれに限定するものではなく、スポットライトなど、それ以外の再生方式でも構わない。他の再生方式の場合であっても、アジマス圧縮を遡って実施することで対応できる。

The FFT processing unit 136 uses the processing device to generate post-FFT data obtained by performing complex fast Fourier transform on the zero-padded data generated by the zero-padding processing unit 134 for each azimuth line and converting the data into the frequency domain. Further, the FFT processing unit 136 performs FFT on the reference function generated by the reference function generation unit 142 described later, and generates a post-FFT reference function by the processing device.
The azimuth compression processing unit 138 performs azimuth compression on the range-compressed data input by the data input unit 112 based on a reference function generated by a reference function generation unit 142, which will be described later, and generates azimuth-compressed data by the processing device. Here, the azimuth compression processing unit 138 performs azimuth compression on the post-FFT data based on the post-FFT reference function. The azimuth compression processing unit 138 performs azimuth compression (correlation processing) by multiplying, for example, one azimuth line of the extracted image and a reference function for azimuth compression in the frequency domain. This achieves high resolution in the azimuth direction in the time domain.
The IFFT processing unit 140 performs inverse fast Fourier transform (IFFT) on the azimuth-compressed data that has been azimuth-compressed by the azimuth compression processing unit 138, and generates post-IFFT data by the processing device. The IFFT processing unit 140 generates an ISAR-processed image by performing IFFT on the data subjected to azimuth compression processing in the frequency domain.
The reference function generation unit 142 generates a reference function by the processing device based on the distance relationship information between the SAR and the target based on the movement information of the SAR and the predicted movement information of the target, and stores the reference function in the storage device 982. For example, the reference function generation unit 142 generates the reference function E _ref of Equation 10 above. The predicted movement information is the predicted movement speed input by the speed input unit 116. For example, Equation 10 above is generated for the range Doppler playback method, but the playback method is not limited to this, and other playback methods such as spotlights may be used. Even in the case of other reproduction methods, it can be handled by retroactively performing azimuth compression.

The storage unit 160 includes a data storage unit 162.
The data storage unit 162 stores in the storage device 982 the data after IFFT obtained by performing IFFT on the data after azimuth compression generated by the azimuth compression processing unit 138. Here, the data storage unit 162 stores the post-IFFT data in the storage device 982 when the definition determination unit 122 determines that the definition is clear. For example, the data storage unit 162 stores, in the storage device 982, an image including a real part and an imaginary part in which a moving target is clarified.

The display unit 170 includes a data display unit 172.
The data display unit 172 displays the post-IFFT data generated by the IFFT processing unit 140 on the display device 984. The data display unit 172 displays the data after IFFT by calculating the power from the complex number.

  Next, the operation of the image sharpening apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 12 is a flowchart illustrating an image sharpening method based on the speed designation method ISAR, which is an operation of the image sharpening apparatus 100 according to the first embodiment.

First, in the data input step (S101), the data input unit 112 uses the input device 980 to input range-compressed data obtained by performing range compression on the target data observed by the SAR. Next, the range migration correction step (S102), the range migration correction unit 132 calculates the correction amount C _r in accordance with the range direction velocity v _R of the target, based on the calculated correction amount C _r, the data The range-compressed data input by the input unit 112 is subjected to range migration correction to generate corrected data. Here, the range migration correction unit 132 receives the distance r (t) between the SAR and the target obtained in a reference function generation step (S106) described later, and based on the received r (t), the range migration correction amount C _r is calculated. For example, the range migration correction unit 132 calculates the correction amount _Cr based on Expression 12. Next, in the zero padding processing step (S103), the zero padding processing unit 134 fills the corrected data generated by the range migration correcting unit 132 with zeros, thereby setting the number of pixels of the corrected data to a power of two. The padding data is generated by the processing device. Here, the zero padding processing unit 134 calculates the number of pixels to be padded with zeros based on, for example, Expressions 13 and 14. Next, in the fast Fourier transform processing step (S104), the FFT processing unit 136 performs FFT on the zero padded data generated by the zero padding processing unit 134 and generates post-FFT data by the processing device.

In part with the above processing, in the accompanying information input step (S105), the accompanying information input unit 120 inputs image accompanying information accompanying the image such as the position of the SAR and the speed of the SAR by the input device 980. Further, here, the reference function information input unit 114, the moving predicted speed at which the predicted travel speed _v A of the target, _{v R} start time alpha _start the synthetic aperture end time of time _{T A_isar} synthetic aperture time _{T A_isar} Synthetic opening time information having α _end is input by the input device 980. Next, in the reference function generation step (S106), the reference function generation unit 142 processes the reference function based on the distance relationship information between the SAR and the target based on the movement information of the SAR and the predicted movement information of the target. And is stored in the storage device 982. For example, the reference function generation unit 142 generates the reference function E _ref of Equation 10 above. In addition, the reference function generation unit 142 outputs r (t) to (S102). Next, in the fast Fourier transform processing step (S107), the FFT processing unit 136 performs FFT on the reference function generated by the reference function generation unit 142 and generates a post-FFT reference function by the processing device.

Next, in the azimuth compression processing step (S108), the azimuth compression processing unit 138 performs the fast Fourier transform processing step (S104) based on the post-FFT reference function generated by the FFT processing unit 136 in the fast Fourier transform processing step (S107). Then, the post-FFT data generated by the FFT processing unit 136 is azimuth-compressed, and the post-azimuth-compressed data is generated by the processing device. Next, in the inverse fast Fourier transform processing step (S109), the IFFT processing unit 140 performs inverse fast Fourier transform (IFFT) on the azimuth-compressed data that has been azimuth-compressed by the azimuth compression processing unit 138, and the post-IFFT data is processed by the processing device. Generate. Next, in the data display step (S110), the data display unit 172 displays the post-IFFT data generated by the IFFT processing unit 140 on the display device 984. Next, in the sharpness determination input step (S111), the sharpness determination input unit 122 inputs, using the input device 980, a determination as to whether or not the data after IFFT displayed by the data display unit 172 is clear. When the sharpness determination input unit 122 inputs that the target is not clear (No in S111), the reference function information input unit 114 displays the predicted moving speeds v _A and v _R that are predicted speeds of movement of the target and the synthetic aperture time. entering through the input device 980 a synthetic aperture time information and a end time alpha _{end the} of T _{A_isar} start time alpha _start the synthetic aperture time _{T A_isar.} Then, the processes from the reference function generation step (S106) and the range migration correction step (S102) are performed again, and the processes are repeated until the image becomes clear. On the other hand, when the sharpness determination input unit 122 inputs that it is clear (Yes in S111), the process proceeds to the data storage step (S112). In the data storage step (S <b> 112), the data storage unit 162 stores in the storage device 982 post-IFFT data obtained by performing IFFT on the post-azimuth compressed data generated by the azimuth compression processing unit 138.

  According to the first embodiment, the target can be reproduced clearly even if different speed clutters are included in the image. Further, according to the first embodiment, the target can be clarified even when the target exists in the presence of other high brightness objects such as land.

  That is, according to the first embodiment, it is possible to realize ISAR processing that does not depend on the intensity of luminance of the target.

Embodiment 2. FIG.
Next, a second embodiment will be described. In the second embodiment, an image sharpening device 100 including a speed measuring device that measures the speed of the target object together with the sharpening of the target image in the first embodiment will be described.

First, the speed calculation of the target by the speed specification method ISAR will be described with reference to FIGS.
FIG. 13 is a diagram showing target speed calculation by the speed designation method ISAR when only one moving target exists. When range-compressed data having only one moving target is input and processed by the speed designation method ISAR, the target is successfully clarified when the speed of the target is input. Here, the speed of the target inputted when the target is sharpened is the correct speed of the target.
FIG. 14 is a diagram illustrating calculation of the speed of a target by the speed designation method ISAR when there is a moving target and a clutter having a speed different from that of the target and having high luminance. If you input the data after range compression in which there is a moving target and a clutter that has a different speed from the target and has strong brightness, and processed by the speed specification method ISAR, the target will be Clutters that are sharpened and have different speeds are blurred. Similar to the case where there is only one moving target, the speed of the target input when the target is sharpened is the correct target speed.

  Next, functions of the image sharpening device 100 according to the second embodiment will be described with reference to FIG. FIG. 15 is a functional block diagram illustrating functions of the image sharpening apparatus 100 according to the second embodiment. Here, only parts different from the function of the image sharpening apparatus 100 according to the first embodiment will be described.

The image sharpening device 100 according to the second embodiment includes a speed determining unit 144 in addition to the image sharpening device 100 according to the first embodiment.
Speed determining unit 144, the sharpness when the decision input unit 122 generates a reference function used to generate the data after azimuth compression type is sharp, predicted velocity v _A of the reference function generating unit 142 is used , V _R is determined by the processing device to be the speed of the target. Here, the speed of the target has a speed in the range direction and a speed in the azimuth direction.

That is, in the flowchart shown in FIG. 12, when the sharpness determination input unit 122 inputs that it is clear in the sharpness determination input step (S111) (Yes in S111), the speed determination unit 144 has the reference function generation unit 142. The processing device determines that the predicted speeds v _A and v _R used by are the target speeds. In the data storage step (S112), the data storage unit 162 stores the predicted speeds v _A and v _R determined by the speed determination unit 144 in the storage device 982 as the target speed.

  According to the second embodiment, the moving speed of the target can be calculated together with the sharpening of the target image.

Embodiment 3 FIG.
Next, Embodiment 3 will be described. In the third embodiment, an image sharpening device 100 including an image sharpness determination device that determines the sharpness of an image of a target will be described. In the above embodiment, the sharpness determination input unit 122 inputs the determination as to whether or not the image is clear, thereby determining the sharpness of the image. However, in the third embodiment, the sharpness of the image is mechanically determined to obtain the sharpest target image and the target speed.

First, a process for obtaining a clear target image in the above embodiment will be described with reference to FIG. FIG. 16 is a diagram illustrating an operation of the image sharpening apparatus 100 that determines the sharpness of an image by inputting a determination as to whether or not the image is clear.
In the image sharpening apparatus 100 that determines the sharpness of an image by inputting a determination as to whether or not the image is clear, first, the image after range compression, the predicted speed in the range direction, the predicted speed in the azimuth direction, and the like. Enter. Next, based on the input data, the speed designation method ISAR processing is performed up to the inverse fast Fourier transform processing step (S109). The generated image is displayed, and it is determined whether the image of the target is clear by visual observation or the like, and the determination is input. If the image is not clear, the above process is repeated until a clear image is obtained.

Next, processing for obtaining a clear target image in the third embodiment will be described with reference to FIG. FIG. 17 is a diagram illustrating the operation of the image sharpening apparatus 100 that mechanically determines the sharpness of an image.
The image sharpening apparatus 100 that mechanically determines the sharpness of an image inputs the image after the range compression, and outputs a mechanically clearest target image.
Therefore, although it took a lot of time to obtain a clear image, such as when the target moves in a complex manner within the synthetic aperture time for ISAR, the problem can be solved by using the method of the third embodiment. Can do.

Next, an overview of the image definition method of the image definition device according to Embodiment 3 will be described with reference to FIGS.
FIG. 18 is a diagram illustrating an example of a case where blurring occurs where an image is not clear. When a reference function that does not match is input to an image after range compression and azimuth compression processing is performed, the image after azimuth compression is blurred and a clear image cannot be obtained. That is, if the predicted speed of the target is different from the actual speed of the target, the reference function does not match, so that a clear image cannot be obtained. In this case, the peak of the amplitude value indicating the luminance of the target of the image after azimuth compression is low.
FIG. 19 is a diagram illustrating an example in which an image becomes clear. When a matching reference function is input to the image after range compression and azimuth compression processing is performed, a clear image that does not blur the image after azimuth compression is obtained. That is, the reference function matches when the predicted speed of the target is equal to the speed of the actual target, and a clear image is obtained. In this case, the peak of the amplitude value indicating the luminance of the target of the image after azimuth compression becomes high.

  Next, functions of the image sharpening device 100 according to the third embodiment will be described with reference to FIG. FIG. 20 is a functional block diagram illustrating functions of the image sharpening device 100 according to the third embodiment. Here, only parts different from the functions of the image sharpening device 100 according to the second embodiment will be described.

The image sharpening device 100 according to the third embodiment includes a sharpness calculation unit 146 in addition to the image sharpening device 100 according to the second embodiment. Further, the image sharpening device 100 according to the third embodiment may not include the sharpness determination input unit 122.
The definition calculator 146 calculates the definition of the image indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression processing unit 138 by the processing device. The sharpness calculation unit 146 searches for the peak value of the amplitude representing the luminance of the pixel of the image indicated by the azimuth compression data generated by the azimuth compression processing unit 138, and the higher the peak value, the clearer the image. Judge that there is.
The speed input unit 116, for example, set the range _v a_max predicted velocity _{v A} of the azimuth _{direction, v A_mix} the range direction of predicted velocity _v range of _{R v r_max,} the _{v R_mix} and azimuth compression number N, less The input speed is calculated as shown in Equation 15, and the calculated speed is input.

  Next, the operation of the image sharpening apparatus 100 according to the third embodiment will be described with reference to FIG. FIG. 21 is a flowchart illustrating an image sharpness determination method for automating image sharpening by the speed designation method ISAR, which is an operation of the image sharpening apparatus 100 according to the third embodiment. Here, only parts different from the operation of the image sharpening apparatus 100 according to the second embodiment will be described.

First, S202 to S204 and S206 to S211 are set as a processing group A, and the processing group A is repeatedly executed while changing the speed input by the speed input unit 116 in a speed input step (S210) described later. For example, the processing group A is repeated N times based on Equation 15 above.
Here, S201 to S209 are the same as S101 to S109, respectively.
At speed input step (S210), the speed input unit 116 inputs the input device 980 the predicted velocity v _a of the predicted velocity v _r and the azimuth direction of a predicted velocity range direction of movement of the target is. Speed input unit 116, for example, set the range _v a_max predicted velocity _{v A} of the azimuth _{direction, v A_mix} the range direction of predicted velocity _v range of _{R v r_max,} the _{v R_mix} and azimuth compression number N, the formula 15 The input speed is calculated as follows, and the calculated speeds v _r and v _a are input. In the sharpness calculation step (S211), the sharpness calculation unit 146 calculates the sharpness of the image indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression processing unit 138 by the processing device. Next, in the speed determination step (S212), the speed determination unit 144 refers to the reference function used to generate the azimuth-compressed data having the highest sharpness calculated by the sharpness calculation unit 146. The predicted speeds v _R and v _A used by the function generator 142 are determined by the processing device as being the speed of the target. Next, in the data storage step (S213), the data storage unit 162 stores, in the storage device 982, the data determined by the definition calculation unit 146 to have the highest definition in the processing group A that has been executed a plurality of times. Here, as in the second embodiment, the data storage unit 162 stores the predicted speeds v _A and v _R input when calculating data determined to have high definition as the target speed.

In the operation of the image sharpening apparatus 100 shown in FIG. 21, a process for searching for the highest sharpness is performed while changing the predicted speeds v _R and v _A. Next, the operation of the image sharpening device 100 that performs processing for searching for the highest sharpness while changing the synthetic aperture time T _{A_isar} in addition to the predicted speeds v _R and v _A will be described with reference to FIG. FIG. 22 is a flowchart illustrating the operation of the image sharpening apparatus 100 that performs a process of searching for the highest sharpness while changing the synthetic opening time T A — _isar in addition to the predicted speeds v _r and v _a . Here, only parts different from the operation of the image sharpening apparatus 100 shown in FIG. 21 will be described.

First, S202 to S204, S206 to S211 and S213 are set as processing group B, and the synthetic aperture time information input by the synthetic aperture time information input unit 118 in the synthetic aperture time information input step (S213) described later is changed. However, the processing group B is repeatedly executed. Treatment group B, for example, a synthetic aperture time T _A of the SAR and M division, repeated each of the M synthetic aperture time times. That is, for each processing group B that is executed M times, the processing group A is executed N times. That is, the processing group A is executed M × N times.
Here, S201 to S212 are the same as the operation of the image sharpening apparatus 100 shown in FIG.
In the synthetic aperture time information input step S213, the synthetic aperture time information input unit 118 uses the input device 980 to input synthetic aperture time information _including the start time α _start of the synthetic aperture time _{TA_isar} and the end time α _end of the synthetic aperture time. To do. Synthetic aperture time information input unit 118 is, for example, a synthetic aperture time T _A of the SAR and M division, inputs the M pieces each synthetic aperture time information.

  According to the third embodiment, it can be mechanically determined whether or not the target image is clear. Therefore, when the movement of the target within the synthetic aperture time for SAR is complicated, it takes a considerable time to obtain a high-quality ISAR image. According to the third embodiment, the time is reduced. It is possible to reduce the time required for obtaining a high-quality ISAR image.

Embodiment 4 FIG.
Next, a fourth embodiment will be described. In the fourth embodiment, an image sharpening device 100 that sharpens an image of a target when the target included in the SAR reproduced image (image after azimuth compression) is blurred will be described.

First, image reproduction by the isolated scattering point method ISAR when an image after azimuth compression is input will be described with reference to FIGS.
FIG. 23 is a diagram showing image reproduction by the isolated scattering point method ISAR when an image after azimuth compression in which a plurality of targets having different velocities exist is input. In this case, as described with reference to FIG. 3, a portion where only one target is present is cut out from the image after azimuth compression, and image reproduction by the isolated scattering point method ISAR is performed, so that an image of the target contained in the cut-out portion is obtained. Can be clarified. However, as described with reference to FIG. 4, if another target (clutter) is included in the portion cut out from the image after azimuth compression other than the target to be clarified, image reproduction by the isolated scattering point method ISAR is performed. The target image will fail to be sharpened even if
FIG. 24 is a diagram showing image reproduction by the isolated scattering point method ISAR when an image after azimuth compression in which a moving target on land exists is input. In this case, even if a portion including the target is cut out from the image after the azimuth compression and the image is reproduced by the isolated scattering point method ISAR, the image of the target fails to be sharpened due to the influence of the reflection from the land of zero speed. .

Next, image reproduction by the speed designation method ISAR when an image after azimuth compression is input will be described with reference to FIGS.
FIG. 25 is a diagram showing image reproduction by the speed designation method ISAR when an image after azimuth compression in which a plurality of targets having different speeds is present is input. In this case, as described in FIG. 5, a portion where only one target is present is cut out from the image after azimuth compression, and the image of the target contained in the cut out portion is obtained by performing image reproduction by the speed designation method ISAR. It can be sharpened. Further, as described with reference to FIG. 6, even if the target segment (clutter) is included in the portion cut out from the image after azimuth compression in addition to the target to be clarified, the image reproduction by the speed designation method ISAR is performed. By performing the above, the image of the target can be clarified.
FIG. 26 is a diagram showing image reproduction by the speed designation method ISAR when an image after azimuth compression in which a moving target on land exists is input. In this case, it is possible to sharpen the image of the target without being affected by the reflection from the land by cutting out a portion including the target from the image after the azimuth compression and performing the image reproduction by the speed designation method ISAR.

Next, a method for sharpening a target image when the target included in the image after azimuth compression by the image sharpening apparatus 100 according to the fourth embodiment is blurred will be described with reference to FIG. FIG. 27 is a diagram illustrating a method for sharpening an image of a target when the target included in the image after azimuth compression by the image sharpening device 100 according to the fourth embodiment is blurred.
First, a portion including the target is cut out from the input image after azimuth compression. In this case, any part may be used as long as the target is included, and clutter may be included. Next, the azimuth compression of the cut image is decompressed. By decompressing azimuth compression, data after range compression is generated. By performing image reproduction by the speed designation method ISAR on the data after the range compression, the target is clarified.

  Next, functions of the image sharpening device 100 according to the fourth embodiment will be described with reference to FIG. FIG. 28 is a functional block diagram illustrating functions of the image sharpening device 100 according to the fourth embodiment. Here, only parts different from the function of the image sharpening apparatus 100 according to the third embodiment will be described.

The image sharpening device 100 according to the fourth embodiment includes an image cutout unit 148 and an azimuth decompression processing unit 150 in addition to the image sharpening device 100 according to the third embodiment.
The image cutout unit 148 cuts out a partial image including the target from the image after azimuth compression input by the data input unit 112.
The azimuth decompression processing unit 150 decompresses azimuth compression for the image after azimuth compression.

  Here, thawing of azimuth compression refers to performing azimuth compression processing in reverse. Here, the azimuth compression processing is azimuth compression processing performed on the input image. Therefore, it is usually considered that the azimuth compression processing is based on the reference function not considering the movement of the target, instead of the azimuth compression processing based on the reference function considering the movement of the target. Therefore, instead of the azimuth compression process based on the reference function considering the movement of the target object shown in the first embodiment, the azimuth decompression process is performed based on the reference function obtained as follows, for example.

In the SAR, due to its imaging principle, the SAR moves at a certain speed. The SAR image always includes SAR flight information, reproduced image position information, and synthetic aperture time, and the relative distance relationship between the SAR and the target shown in Expression 16 can be calculated. As a result, the Doppler frequency change can be calculated as shown in Equation 17 in the same manner as in the first embodiment. Then, the reference function E _ref for azimuth compression used at the time of reproducing the SAR image can be obtained as shown in Equation 18.

なお、ここでは、レンジ−ドップラ再生方式を対象としているが、これに限定するわけではなく、スポットライトなど、それ以外の再生方式でもアジマス圧縮を逆に実施することで対応できる。

Here, the range-Doppler reproduction method is targeted, but the present invention is not limited to this, and other reproduction methods such as spotlight can be dealt with by reversely performing azimuth compression.

Next, based on FIG. 29 and FIG. 30, the influence of the movement of the target in the frequency domain is shown below using the formula described in the first embodiment, and the influence of azimuth decompression will be described. FIG. 29 is a diagram illustrating the influence when the target moves in the range direction in the frequency domain. FIG. 30 is a diagram illustrating the influence when the target moves in the azimuth direction in the frequency domain.
As shown in FIG. 29, when the target moves in the range direction in the frequency domain, there is no change in the band, but a shift occurs. As shown in FIG. 30, when the target moves in the azimuth direction in the frequency domain, the band changes when the target moves in the direction opposite to the SAR. However, in other cases, it falls within the band of the target that does not move.

  When processing is reversed from SLC (single look complex) after convolution in the frequency domain, data lost due to frequency shift or band expansion accompanying movement cannot be reproduced. However, this is only a case where the out-of-band portion of the reference function assuming a stationary body is completely zero, and thus is generally not a problem.

  Next, the operation of the image sharpening device 100 according to the fourth embodiment will be described with reference to FIG. FIG. 31 is a flowchart illustrating an image sharpening method using a speed designation method ISAR process for a SAR reproduced image, which is an operation of the image sharpening apparatus 100 according to the fourth embodiment.

  In the data input step (S301), the data input unit 112 inputs an image after azimuth compression. Next, in the image cutout step (S302), the image cutout unit 148 cuts out a partial image including the target from the image after azimuth compression input by the data input unit 112. Next, in the zero padding processing step (S303), the zero padding processing unit 134 sets the number of pixels of the cut-out image to a power of 2 by padding the cut-out image with 0. The zero padding method may be the same as the method shown in the first embodiment. Next, in the fast Fourier transform processing step (S304), the FFT processing unit 136 performs FFT on the zero padded data generated by the zero padding processing unit 134 and generates post-FFT data by the processing device.

  In parallel with the above processing, in the incidental information input step (S305), the incidental information input unit 120 inputs image incidental information associated with the image such as the position of the SAR and the speed of the SAR by the input device 980. Next, in the azimuth compression reference function generation step (S306) for the stationary target, the reference function generation unit 142 generates a reference function that does not consider the movement of the target by the processing device. Next, in the fast Fourier transform processing step (S307), the FFT processing unit 136 performs FFT on the reference function generated by the reference function generation unit 142 and generates a post-FFT reference function by the processing device.

  Next, in the azimuth decompression processing step (S308), the azimuth decompression processing unit 150 performs the fast Fourier transform processing step (S304) based on the post-FFT reference function generated by the FFT processing unit 136 in the fast Fourier transform processing step (S307). The FFT data generated by the FFT processing unit 136 is azimuth-decompressed, and the azimuth-decompressed data is generated by the processing device. Next, in the inverse fast Fourier transform processing step (S309), the IFFT processing unit 140 performs IFFT on the data after azimuth decompression performed by the azimuth decompression processing unit 150, and generates the data after IFFT by the processing device. Then, in the image sharpening process step (S310) by the speed designation system ISAR process, the image reproduction by the speed designation system ISAR process shown in the above embodiment is performed. In the data storage step (S311), the data storage unit 162 stores the reproduced image and the calculated speed as in the above embodiment.

  According to the fourth embodiment, the speed designation method ISAR process can be performed using SAR reproduction image, ISAR reproduction image, or the like as input data. Therefore, it is possible to sharpen a target that is blurred because it is included in a SAR reproduction image that can be usually obtained and that is blurred because it exists on land.

Embodiment 5 FIG.
Next, a fifth embodiment will be described. In the fifth embodiment, a position specifying device 200 that specifies the correct position of a target that has shifted in the azimuth direction depending on the speed in the range direction of the target will be described.

  First, based on FIG. 32, FIG. 33 and FIG. 34, a matching method for matching the wake and the ship and specifying the correct position of the target will be described.

  FIG. 32 is a diagram showing a matching method in the case where there is only one target ship in the SAR reproduction image and the wake is clear. In this case, since the correspondence between the wake and the ship is clear, the wake and the ship can be matched. Therefore, the correct position of the ship can be specified by shifting the ship to the position of the wake.

  FIG. 33 is a diagram showing a matching method in the case where there is only one target ship in the SAR reproduction image and there is no wake, and the wake is unclear. In this case, since the wake cannot be detected, the wake and the ship cannot be matched. Therefore, the correct position of the ship cannot be specified.

  FIG. 34 is a diagram showing a matching method in the case where a plurality of ships as targets are present in the SAR reproduction image and the wake is clear. In this case, since the correspondence between the wake and the ship is unclear only by the information of the SAR reproduction image, the wake and the ship cannot be matched. Therefore, the correct position of the ship cannot be specified.

  Next, a method for specifying the correct position of the target using the isolated scattering point method ISAR will be described with reference to FIGS.

  FIG. 35 is a diagram showing a method using the isolated scattering point method ISAR when there is only one ship as a target in the SAR reproduction image, when there is no wake, and when the wake is unclear. . In this case, the presence or absence of the wake is not affected, and the correct position of the target can be specified by obtaining the speed of the target in the range direction based on the isolated scattering point method ISAR by a method described later.

  FIG. 36 is a diagram showing a method using the isolated scattering point method ISAR when there are a plurality of ships as targets in the SAR reproduction image and there is no wake. When there are a plurality of targets, the method described below cannot determine the correct position of the target because the speed of the target in the range direction cannot be obtained based on the isolated scattering point method ISAR.

Next, a method for obtaining the speed of the target in the range direction by using an isolated scattering point method ISAR or the like will be described.
First, a range migration curve is acquired by an isolated scattering point method ISAR or the like. Also, a range migration curve obtained when the target is not moving is acquired. By calculating the difference between the two range migration curves, a straight line indicating the movement of the target in the range direction can be calculated.
FIG. 37 is a diagram showing a method for obtaining the speed of the target in the range direction from the range migration curve acquired by observation and the range migration curve when the target does not move.
As shown in FIG. 37, the speed of the target in the range direction is calculated from the angle α of the straight line indicating the movement of the target in the range direction obtained from the difference between the two range migration curves and the moving speed of the SAR. Can be calculated. That is, if the speed of the target in the range direction is v _r and the speed of the SAR in the azimuth direction is v _P , then v _r = v _P tanα.

Next, a method of calculating the shift amount in the azimuth direction depending on the speed in the range direction of the target based on the speed in the range direction of the target obtained by the above method will be described.
The shift amount in the azimuth direction depending on the speed of the target in the range direction can be calculated by Δx = (v _r / V _P ) · _RC . Here, [Delta] x, the amount of shift in the azimuth direction, v _r is the distance the speed of the range direction of a target, V _P, the speed of the SAR, R _C is the SAR and target in the synthetic aperture center It is. By substituting the speed in the range direction of the target obtained by the above method into this equation, the shift amount in the azimuth direction can be calculated depending on the speed in the range direction of the target.

  Therefore, the correct position of the target can be specified by obtaining the speed of the target in the range direction.

  Next, a method for specifying the correct position of the target using the speed designation method ISAR will be described with reference to FIG. FIG. 38 is a diagram showing a method using the speed designation method ISAR when there are a plurality of ships as targets in the SAR reproduction image and there is no wake. In this case, according to the speed designation method ISAR, as shown in the above embodiment, it is possible to obtain the speed in the range direction of each of the plurality of targets. Accordingly, the shift amount in the azimuth direction can be calculated depending on the range direction speed of the target by substituting the obtained range direction speed into the above equation. Therefore, the correct position of the target can be specified.

  Next, an image reproduction apparatus that reproduces an image by correcting the target to the correct position based on FIGS. 39 and 40 will be described. Here, as a method for specifying the correct position of the target, a method using the speed designation method ISAR is used. However, the method for specifying the correct position of the target is not limited to this, and other methods described above may be used.

FIG. 39 is a diagram illustrating a method for reproducing an image by correcting a target in the correct position when only one target exists.
First, an SAR reproduction image including a target shifted in the azimuth direction with blur due to movement is input. A speed designation system ISAR is applied to this image to obtain an image with a clear target and a speed in the range direction. Next, the shift amount in the azimuth direction is calculated from the speed in the range direction. Then, the position of the target of the image in which the target obtained by the speed specification method ISAR is sharpened is corrected by the shift amount in the azimuth direction calculated from the coordinates of the target of the input SAR reproduction image. , Play the image.

FIG. 40 is a diagram showing a method for reproducing an image by correcting a target in a correct position when there are a plurality of targets.
First, a SAR reproduction image including a plurality of targets shifted in the azimuth direction with blur due to movement is input. A speed designation method ISAR is applied to this image to obtain an image in which each of the plurality of targets is sharpened and a speed in the range direction of each of the plurality of targets. Next, the shift amount in the azimuth direction of each of the plurality of targets is calculated from the speed in the range direction of each of the plurality of targets. Then, the position of each target in the image in which each of the plurality of targets obtained by the speed designation method ISAR is sharpened is moved in the azimuth direction calculated from the coordinates of each of the plurality of targets in the input SAR reproduction image. The position is corrected by the shift amount and the image is reproduced.

  Next, the function of the position specifying device 200 that specifies the position of the target by the speed specifying method ISAR will be described with reference to FIG. FIG. 41 is a functional block diagram showing functions of the position specifying device 200 that specifies the position of the target by the speed specifying method ISAR. The position specifying device 200 has an image playback function and is an example of an image playback device.

  The position specifying device 200 specifies the position of the target observed by the SAR. The position specifying device 200 includes a speed measurement unit 210, a shift amount calculation unit 220, a SAR reproduction image input unit 222, a position specification unit 224, a position correction unit 226, an image reproduction unit 228, an input device 980, a storage device 982, and a display device 984. Is provided.

  The speed measurement unit 210 measures the range direction speed, which is the moving speed of the target in the range direction, by the processing device and stores it in the storage device 982. The speed measurement unit 210 includes the image sharpening device 100 and the speed extraction unit 212 described in the above embodiment. The image sharpening device 100 included in the speed measurement unit 210 is an example of a speed measurement device. The image sharpening device 100 included in the speed measurement unit 210 does not have to have all the functions described in the above embodiment. For example, refer to the data input unit 112, the speed input unit 116, and the azimuth compression processing unit 138. A function generation unit 142, a speed determination unit 144, and a definition calculation unit 146 are provided. The image sharpening device 100 included in the speed measurement unit 210 is not limited to this, and may have any configuration as long as the speed in the range direction can be specified. It does not matter even if it has a function that can measure speed by ISAR. The speed extraction unit 212 extracts the range direction speed from the movement speed determined by the speed determination unit 144 and stores it in the storage device 982.

The shift amount calculation unit 220 calculates the shift amount in the azimuth direction by the processing device based on the range direction speed measured by the speed measurement unit 210 and stores the shift amount in the storage device 982. The shift amount calculation unit 220 calculates the shift amount in the azimuth direction based on Δx = (v _r / V _P ) · _RC .
The SAR playback image input unit 222 inputs the SAR playback image observed by the SAR using the input device 980.
Based on the shift amount calculated by the shift amount calculation unit 220 and the coordinates of the target of the SAR playback image input by the SAR playback image input unit 222, the position specifying unit 224 specifies and stores the position of the target by the processing device. Store in device 982.
The position correction unit 226 generates a corrected image obtained by correcting the target of the image generated by the speed specification method ISAR to the position specified by the position specifying unit 224 by the processing device, and stores the corrected image in the storage device 982.
The image reproduction unit 228 reproduces the corrected image generated by the position correction unit 226.

Next, the operation of the position specifying device 200 will be described with reference to FIG. FIG. 42 is a flowchart showing the operation of the position specifying device 200.
First, S402 to S404 are set as a processing group C, and the target object included in the image input in the SAR reproduction image input step (S401) described later is repeated.
In the SAR reproduction image input step (S401), the SAR reproduction image input unit 222 inputs the SAR reproduction image observed by the SAR by the input device 980. Next, in the speed measurement step (S402), the speed measurement unit 210 measures the range direction speed, which is the moving speed of the target in the range direction, by the processing device and stores it in the storage device 982. Next, in the shift amount calculation step (S403), the shift amount calculation unit 220 calculates the shift amount in the azimuth direction by the processing device based on the range direction speed measured by the speed measurement unit 210 and stores it in the storage device 982. To do. Next, in the position specifying step (S404), the position specifying unit 224 sets the target based on the shift amount calculated by the shift amount calculating unit 220 and the coordinates of the target of the SAR playback image input by the SAR playback image input unit 222. The position of the object is specified by the processing device and stored in the storage device 982. Next, in the position correction step (S405), the position correction unit 226 generates a corrected image obtained by correcting the target of the image generated by the speed specification method ISAR to the position specified by the position specifying unit 224 by the processing device. And stored in the storage device 982. Next, in the image reproduction step (S406), the image reproduction unit 228 reproduces the corrected image generated by the position correction unit 226.

  Next, the function of the position specifying device 200 for specifying the position of the target by the isolated scattering point method ISAR will be described with reference to FIG. FIG. 43 is a functional block diagram showing functions of the position specifying device 200 for specifying the position of the target by the isolated scattering point method ISAR. Here, only the parts different from the position specifying device 200 that specifies the position of the target by the speed specifying method ISAR will be described.

The position specifying device 200 that specifies the position of the target by the isolated scattering point method ISAR includes a moving straight line calculation unit 214 and a velocity calculation unit 216. In addition, the position specifying device 200 that specifies the position of the target by the isolated scattering point method ISAR does not need to include the image sharpening device 100 and the speed extraction unit 212.
The movement straight line calculation unit 214 calculates a straight line indicating the movement of the target in the range direction based on the acquired range migration curve and the range migration curve obtained when the target is not moving, and stores it in the storage device 982. Remember.
The speed calculation unit 216 calculates the range direction speed based on the straight line calculated by the moving straight line calculation unit 214 and stores the range direction speed in the storage device 982.

  According to the fifth embodiment, the correct position of the target that has shifted in the azimuth direction due to the movement of the target is specified even when the target is dense or on land. can do. In addition, since the image sharpened by the speed designation method ISAR can be obtained together with the correct position information, the target can be visualized.

It is the figure which showed an example of the external appearance of the image sharpening apparatus 100 concerning embodiment. It is a figure which shows an example of the hardware constitutions of the image sharpening apparatus 100 in embodiment. It is a figure which shows the sharpening of the target by the isolated scattering point system ISAR when there is only one target that moves. It is a figure which shows the sharpening of the target by the isolated scattering point system ISAR when there is a moving target and a clutter having a different speed from the target and having a high luminance. It is a figure which shows the sharpening of the target by the speed designation | designated system ISAR when only one target which moves exists. It is a figure which shows the sharpening of the target by the speed designation | designated system ISAR when the target which moves and the clutter which has a different speed from a target and a brightness | luminance exists. It is a figure showing the relative relationship (distance) after t second of SAR and a stationary body. It is a figure which shows the movement by rotation of the stationary body in FIG. It is a figure showing the relative relationship (distance) after t second of SAR and a mobile body. It is a figure which shows the movement of the mobile body in FIG. FIG. 2 is a functional block diagram illustrating functions of the image sharpening device 100 according to the first embodiment. 3 is a flowchart illustrating a shake target sharpening method by a speed designation method ISAR, which is an operation of the image sharpening device 100 according to the first embodiment. It is a figure which shows the speed calculation of the target by speed designation | designated system ISAR when only one target which moves exists. It is a figure which shows the speed calculation of the target by the speed designation | designated system ISAR when the target which moves and the clutter which has a speed different from a target, and a brightness | luminance exists. FIG. 4 is a functional block diagram illustrating functions of an image sharpening device 100 according to a second embodiment. It is a figure which shows operation | movement of the image sharpening apparatus 100 which judges the clarity of an image by inputting the determination whether an image is clear. It is a figure which shows operation | movement of the image sharpening apparatus 100 which mechanically determines the definition of an image. It is the figure which showed the example in case the blurring which an image does not become clear occurs. It is the figure which showed the example in case an image becomes clear. FIG. 9 is a functional block diagram illustrating functions of an image sharpening device 100 according to a third embodiment. 12 is a flowchart illustrating an automatic method of image sharpening by a speed designation method ISAR, which is an operation of the image sharpening device 100 according to the third embodiment. It is a flowchart which shows operation | movement of the image sharpening apparatus 100 which performs the process which searches the thing with the highest sharpness, changing also about synthetic | combination opening time in addition to prediction speed. It is the figure which showed the image reproduction by the isolated scattering point system ISAR when the image after the azimuth compression in which a plurality of targets having different velocities exist is input. It is the figure which showed the image reproduction by the isolated scattering point system ISAR when the image after the azimuth compression in which the land movement target exists is input. It is the figure which showed the image reproduction by the speed designation | designated system ISAR when the image after the azimuth compression in which the several target from which speed differs exists is input. It is the figure which showed the image reproduction by the speed designation | designated system ISAR when the image after azimuth compression in which the land movement target exists is input. FIG. 10 is a diagram illustrating a method for sharpening an image of a target when the target included in the image after azimuth compression by the image sharpening device according to the fourth embodiment is blurred. FIG. 6 is a functional block diagram illustrating functions of an image sharpening device 100 according to a fourth embodiment. It is a figure which shows the influence at the time of a target moving to the range direction in a frequency domain. It is a figure which shows the influence when a target moves to an azimuth direction in a frequency domain. 10 is a flowchart illustrating a shake target sharpening method using a speed designation method ISAR process for a SAR reproduced image, which is an operation of the image sharpening apparatus 100 according to the fourth embodiment. It is the figure shown about the matching method in case only one ship which is a target exists in a SAR reproduction | regeneration image, and a wake is clear. It is the figure which showed about the matching method when only one ship which is a target object exists in a SAR reproduction image, a wake does not exist, and a wake is unclear. It is the figure shown about the matching method in case the ship which is a target object exists in SAR reproduction | regeneration image, and a wake is clear. It is the figure which showed about the method using the isolated scattering point system ISAR when there exists only one ship which is a target in a SAR reproduction | regeneration image, a wake does not exist, and a wake is unclear. It is the figure which showed about the method using the isolated scattering point system ISAR when the ship which is a target exists in a SAR reproduction image, and there is no wake. It is the figure which showed the method of calculating | requiring the speed to the range direction of a target object from the range migration curve acquired by observation, and the range migration curve when a target object does not move. It is the figure which showed about the method using the speed designation | designated system ISAR when the ship which is a target object exists in a SAR reproduction | regeneration image, and a wake does not exist. FIG. 10 is a diagram illustrating a method for correcting an object to a correct position and reproducing an image when only one object exists. It is the figure which showed about the method of correct | amending the target in the case where multiple target exists, and reproducing an image. It is a functional block diagram which shows the function of the position specification apparatus 200 which specifies the position of a target object by speed designation | designated system ISAR. 5 is a flowchart showing the operation of the position specifying device 200. It is a functional block diagram which shows the function of the position specification apparatus 200 which pinpoints the position of a target object by the isolated scattering point system ISAR.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 100 Image sharpening apparatus, 110 input part, 112 Data input part, 114 Reference function information input part, 116 Speed input part, 118 Synthetic opening time information input part, 120 Accompanying information input part, 122 Sharpness determination input part, 130 Process , 132 Range migration correction unit, 134 Zero padding processing unit, 136 FFT processing unit, 138 Azimuth compression processing unit, 140 IFFT processing unit, 142 Reference function generation unit, 144 Speed determination unit, 146 Sharpness calculation unit, 148 Image cut Output unit, 150 azimuth decompression processing unit, 160 storage unit, 162 data storage unit, 170 display unit, 172 data display unit, 200 position specifying device, 210 speed measurement unit, 212 speed extraction unit, 214 moving line calculation unit, 216 speed Calculation unit, 220 shift amount calculation unit, 222 SAR playback image Power unit, 224 position specifying unit, 226 position correcting unit, 228 image reproducing unit, 901 CRT display device, 902 K / B, 903 mouse, 904 FDD, 905 CDD, 908 database, 909 system unit, 910 server, 911 CPU, 912 bus, 913 ROM, 914 RAM, 915 communication board, 920 magnetic disk unit, 921 OS, 922 window system, 923 program group, 924 file group, 931 telephone, 932 FAX machine, 940 Internet, 941 gateway, 942 LAN, 980 input device, 982 storage device, 984 display device.

Claims (7)

In a position specifying device for specifying the position of a target observed by SAR (Synthetic Aperture Radar),
A speed measuring unit that measures the speed in the range direction, which is the moving speed of the target in the range direction, by the processing device and stores it in the storage device;
Based on the range direction speed measured by the speed measurement unit, a shift amount calculation unit that calculates a shift amount in the azimuth direction by a processing device and stores the shift amount in a storage device;
A SAR reproduction image input unit for inputting an SAR reproduction image observed by the SAR by an input device;
Based on the shift amount calculated by the shift amount calculation unit and the coordinates of the target of the SAR reproduction image input by the SAR reproduction image input unit, the position of the target is specified by the processing device and stored in the storage device. and a part,
The speed measuring unit is
A data input unit that inputs range-compressed data obtained by performing range compression on the target data observed by the SAR by an input device;
A speed input unit that inputs a plurality of predicted moving speeds having a predicted speed in the range direction and a predicted speed in the azimuth direction by an input device;
A plurality of reference functions are obtained from each predicted movement speed of the plurality of predicted movement speeds input by the speed input unit, and distance relation information between the SAR and the target based on the movement information of the SAR and the predicted movement information of the target. A reference function generation unit that is generated by the processing device and stored in the storage device;
Based on each reference function of the plurality of reference functions generated by the reference function generation unit, the range-compressed data input by the data input unit is azimuth-compressed, and a plurality of azimuth-compressed data is generated by the processing device and stored in the storage device. An azimuth compression processing unit for storing;
A sharpness calculation unit that calculates the sharpness of an image indicated by each azimuth-compressed data of the plurality of post-azimuth-compressed data generated by the azimuth compression processing unit by the processing device and stores it in a storage device;
When generating the reference function used to generate the azimuth compressed data having the highest definition calculated by the definition calculation unit, the predicted movement speed input in the distance relation information is the movement speed of the target A speed determination unit that is determined by the processing device and stored in the storage device;
A speed extracting unit that extracts the range direction speed from the moving speed determined by the speed determining unit and stores the extracted speed in the storage device;
Localization device according to claim Rukoto equipped with. The position specifying device according to claim 1, wherein the shift amount calculation unit calculates the shift amount by Δx = (vr / VP) · RC.
Δx: shift amount in the azimuth direction,
vr: speed in the range direction,
VP: Your own speed,
Rc: Distance between the SAR and the target at the center of the synthetic aperture The speed measuring unit is
Based on the acquired range migration curve and the range migration curve obtained when the target is not moving, a movement straight line calculation unit that calculates a straight line indicating movement of the target in the range direction and stores it in the storage device;
The basis of the linear movement of the linear calculation unit has calculated, the position specifying device according to claim 1, wherein further comprising a speed calculating unit for storing calculated in the storage device range direction velocity. The speed measuring unit measures the moving speed of each target in the range direction of the plurality of targets,
The shift amount calculation unit calculates a shift amount in the azimuth direction of each target based on the moving speed of each target of the plurality of targets measured by the speed measurement unit,
The position specifying unit determines the position of each target based on the shift amount of each target calculated by the shift amount calculation unit and the coordinates of the target of the SAR playback image input by the SAR playback image input unit. Identify
The position specifying device according to any one of claims 1 to 3, further comprising: In an image reproduction device for reproducing an image observed by SAR (Synthetic Aperture Radar),
A speed measurement unit to be stored in the storage device range direction speed is a movement speed of the range direction of a target measurement to,
Based on the range direction speed measured by the speed measurement unit, a shift amount calculation unit that calculates a shift amount in the azimuth direction by a processing device and stores the shift amount in a storage device;
A SAR reproduction image input unit for inputting a SAR reproduction image observed by the SAR;
Based on the shift amount calculated by the shift amount calculation unit and the coordinates of the target of the SAR reproduction image input by the SAR reproduction image input unit, the position of the target is specified by the processing device and stored in the storage device. And
A position correcting unit that generates a corrected image obtained by correcting the target of the image generated by the speed specifying method ISAR by the processing device to the position specified by the position specifying unit, and stores the corrected image in the storage device;
An image reproduction unit that reproduces the corrected image generated by the position correction unit ,
The speed measurement unit
A data input unit that inputs range-compressed data obtained by performing range compression on the target data observed by the SAR by an input device;
A speed input unit that inputs a plurality of predicted moving speeds having a predicted speed in the range direction and a predicted speed in the azimuth direction by an input device;
A plurality of reference functions are obtained from each predicted movement speed of the plurality of predicted movement speeds input by the speed input unit, and distance relation information between the SAR and the target based on the movement information of the SAR and the predicted movement information of the target. A reference function generation unit that is generated by the processing device and stored in the storage device;
Based on each reference function of the plurality of reference functions generated by the reference function generation unit, the range-compressed data input by the data input unit is azimuth-compressed, and a plurality of azimuth-compressed data is generated by the processing device and stored in the storage device. An azimuth compression processing unit for storing;
A sharpness calculation unit that calculates the sharpness of an image indicated by each azimuth-compressed data of the plurality of post-azimuth-compressed data generated by the azimuth compression processing unit by the processing device and stores it in a storage device;
When generating the reference function used to generate the azimuth compressed data having the highest definition calculated by the definition calculation unit, the predicted movement speed input in the distance relation information is the movement speed of the target A speed determination unit that is determined by the processing device and stored in the storage device;
A speed extracting unit that extracts the range direction speed from the moving speed determined by the speed determining unit and stores the extracted speed in the storage device;
Image reproducing apparatus according to claim Rukoto equipped with. In the position specifying method of the position specifying device for specifying the position of the target observed by SAR (Synthetic Aperture Radar),
A speed measuring step in which the speed measuring unit measures the speed in the range direction, which is the moving speed of the target in the range direction, by the processing device and stores it in the storage device;
Based on the speed in the range direction measured in the speed measurement step, a shift amount calculation step in which the shift amount calculation unit calculates the shift amount in the azimuth direction by the processing device and stores it in the storage device,
A SAR reproduction image input step in which the SAR reproduction image input unit inputs the SAR reproduction image observed by the SAR by the input device;
Based on the shift amount calculated in the shift amount calculation step and the coordinates of the target of the SAR reproduction image input in the SAR reproduction image input step, the position specifying unit specifies the position of the target by the processing device and stores it in the storage device. and a position specifying step of,
The speed measurement step includes
A data input step of inputting range-compressed data obtained by performing range compression on the target data observed by the SAR by an input device;
A speed input step of inputting a plurality of predicted moving speeds having a predicted speed in the range direction and a predicted speed in the azimuth direction by an input device;
A plurality of reference functions are obtained from the predicted movement speeds of the plurality of predicted movement speeds input in the speed input step, and the distance relationship information between the SAR and the target based on the movement information of the SAR and the predicted movement information of the target. A reference function generation step generated by the processing device and stored in the storage device;
Based on the reference functions of the plurality of reference functions generated in the reference function generation step, the range-compressed data input in the data input step is azimuth-compressed, and a plurality of azimuth-compressed data is generated by the processing device and stored in the storage device. Storing azimuth compression processing steps;
A sharpness calculation step of calculating a sharpness of an image indicated by each post-azimuth compression data of the plurality of post-azimuth compression data generated in the azimuth compression processing step by a processing device and storing the sharpness in a storage device;
When generating the reference function used to generate the azimuth-compressed data having the highest definition calculated in the above-described definition calculation step, the predicted movement speed input in the distance relation information is the movement speed of the target A speed determination step of determining by the processing device and storing in the storage device;
A speed extracting step of extracting a range direction speed from the moving speed determined in the speed determining step and storing it in a storage device;
Location method, wherein Rukoto equipped with. In the position specifying program of the position specifying device for specifying the position of the target observed by SAR (Synthetic Aperture Radar),
A speed measuring step in which the speed measuring unit measures the speed in the range direction, which is the moving speed of the target in the range direction, by the processing device and stores it in the storage device;
Based on the speed in the range direction measured in the speed measurement step, a shift amount calculation step in which the shift amount calculation unit calculates the shift amount in the azimuth direction by the processing device and stores it in the storage device,
A SAR reproduction image input step in which the SAR reproduction image input unit inputs the SAR reproduction image observed by the SAR by the input device;
Based on the shift amount calculated in the shift amount calculation step and the coordinates of the target of the SAR reproduction image input in the SAR reproduction image input step, the position specifying unit specifies the position of the target by the processing device and stores it in the storage device. and a position specifying step of cause the computer to execute,
In the above speed measurement process,
A data input process in which the range-compressed data obtained by performing range compression on the target data observed by the SAR is input by an input device;
A speed input process of inputting a plurality of predicted moving speeds having a predicted speed in the range direction and a predicted speed in the azimuth direction by an input device;
A plurality of reference functions are obtained from each predicted movement speed of the plurality of predicted movement speeds input in the speed input process, and distance relation information between the SAR and the target based on the movement information of the SAR and the predicted movement information of the target. A reference function generation process generated by the processing device and stored in the storage device;
Based on the reference functions of the plurality of reference functions generated in the reference function generation processing, the range-compressed data input in the data input processing is azimuth-compressed, and a plurality of azimuth-compressed data is generated by the processing device and stored in the storage device. Azimuth compression processing to memorize,
A sharpness calculation process in which the processing device calculates the sharpness of the image indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression processing;
When the reference function used to generate the azimuth-compressed data having the highest definition calculated in the above-described definition calculation process is generated, the predicted moving speed input in the distance relation information is the moving speed of the target Speed determination processing determined by the processing device and stored in the storage device;
A speed extraction process for extracting the range direction speed from the movement speed determined in the speed determination process and storing the speed in the storage device;
Localization program characterized Rukoto cause the computer to execute.

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