JP4834535B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus that compresses and records captured images.

  In recent years, MPEG2 and H.264 encoding methods have been established as high-efficiency encoding techniques in video recording apparatuses such as digital video cameras and DVD (Digital Versatile Disk) recorders. Various studies have been made on these encoding methods in order to improve the encoding efficiency.

  An imaging apparatus having a camera processing unit and an encoding (recording) unit such as a digital video camera can acquire camera status information (for example, a focus position and a white balance value) obtained from control data of the camera processing unit. Encoding efficiency is improved by setting encoding parameters (for example, bit rate, image complexity, etc.) such as a target code amount used in the code amount control of the encoding process according to the camera status information. It is known (see, for example, Patent Document 1).

The code amount control of the MPEG2 encoding method is explained using the example of TM5 (Test Model Editing Committee: "Test Model 5", ISO / IEC, JTC / SC29 / WG11 / n0400 (Apr. 1993)) as a reference soft encoder. To do. The code amount control of TM5 is performed in the following three steps.
(Step 1)

The target code amount of the picture to be encoded from now is determined. Rgop, which is a code amount that can be used in the current GOP (Group Of Pictures), is calculated by the following equation (1).
Rgop = (ni + np + nb) × (bits_rate / picture_rate) (1)
Here, ni, np, and nb are the number of remaining pictures in the current GOP of I, P, and B pictures, bits_rate represents the target bit rate, and picture_rate represents the picture rate.

Further, the complexity of the picture is obtained from the encoding result for each of the I, P, and B pictures by the following equation (2).
Xi = Ri × Qi
Xp = Rp × Qp
Xb = Rb × Qb (2)
Here, Xi, Xp, and Xb are also referred to as complexity. Ri, Rp, and Rb are code amounts obtained as a result of encoding I, P, and B pictures, respectively. Qi, Qp and Qb are average values of Q scales in all macroblocks in the I, P and B pictures, respectively.

From the equations (1) and (2), the target code amounts Ti, Tp, and Tb for each of the I, P, and B pictures can be obtained by the following equation (3).
Ti = max {(Rgop / (1 + ((Np × Xp) / (Xi × Kp)) + ((Nb × Xb) / (Xi × Kb)))) (bit_rate / (8 × picture_rate))}
Tp = max {(Rgop / (Np + (Nb × Kp × Xb) / (Kb × Xp))) (bit_rate / (8 × picture_rate))}
Tb = max {(Rgop / (Nb + (Np × Kb × Xp) / (Kp × Xb))) (bit_rate / (8 × picture_rate))} (3)
Where Np and Nb are the remaining number of P and B pictures in the current GOP, respectively, and the constants Kp and Kb are
Kp = 1.0
Kb = 1.4
It is.
(Step 2)

Three virtual buffers are used for each I, P, and B picture, and the difference between the target code amount and the generated code amount obtained by the equation (3) is managed. The data accumulation amount of the virtual buffer is fed back, and the reference value of the Q scale for the macroblock to be encoded next is set so that the actual generated code amount approaches the target code amount based on the data accumulation amount. For example, when the current picture type is a P picture, the difference between the target code amount and the generated code amount can be obtained by an arithmetic process according to the following equation (4):
d _{p, j} = d _{p, 0} + B _{p, j-1} -((Tp × (j-1)) / MB_cnt) (4)
It becomes. Here, the subscript j is the number of the macroblock in the picture, dp _{, 0} indicates the initial fullness of the virtual buffer, Bp _{, j} is the total code amount up to the jth macroblock, and MB_cnt is in the picture Indicates the number of macroblocks.

Next, using d _{p, j} (hereinafter abbreviated as d _j ), the reference value of the Q scale in the j-th macroblock is obtained as shown in the following equation (5).
Q _j = (d _j × 31) / r (5)
It becomes. here,
r = 2 x bits_rate / picture_rate (6)
It is.
(Step 3)

The quantization scale is finally determined based on the spatial activity of the macroblock to be encoded so that the visual characteristics, that is, the quality of the decoded image is improved. Specifically, in the following formula (7):
ACT _j = 1 + min (vblk1, vblk2, ……, vblk8) (7)
Calculate In Equation (7), vblk1 to vblk4 indicate the spatial activity in the 8 × 8 pixel sub-block in the frame structure macroblock, and vblk5 to vblk8 indicate the spatial activity in the 8 × 8 pixel subblock in the field structure macroblock. Show. Here, the calculation of the space activity can be obtained by the following equations (8) and (9).
vblk = Σ (P _i −P _bar ) 2 (8)
P _bar = (1/64) × ΣP _i (9)
Here, P _i is a pixel value in the i-th macroblock, and Σ in the equations (8) and (9) is a cumulative addition of i = 1 to 64.

Next, ACT _j obtained by the equation (7) is normalized by the following equation (10).
N_ACT _j = (2 x ACT _j + AVG_ACT) / (ACT _j + AVG_ACT) (10)
Here, AVG_ACT is a reference value of ACT _j in a previously encoded picture. Finally, the quantization scale (Q scale value) MQUANT _j is expressed by the following equation (11).
MQUANT _j = Q _j × N_ACT _j (11)
Is required.

According to the above TM5 algorithm, a large amount of code is allocated to the I picture by the processing in step 1, and furthermore, a flat portion (a portion with low spatial activity) that is visually noticeable in the picture. Thus, a large amount of code is distributed.
JP 2002-369142 A

  In the conventional TM5 system, there is no particular definition regarding the initial value to be encoded, and the complexity (complexity) and fullness value (initial quantization scale code) of each picture used when calculating the target code amount in step 1 ) Uses numerical values determined empirically. For this reason, it is difficult to set a target code amount according to image characteristics for several GOPs after the start of recording.

  The average activity (AVG_ACT) used in step 3 is also a numerical value (400 in TM5) determined empirically. Therefore, there is a possibility that the activity is biased to an extremely small or large activity depending on the difficulty level of the image in the first frame of encoding.

  As described in Patent Document 1, even in a method of setting initial encoding parameters such as a target code amount using camera status information, a camera in a period in which an encoding processing unit is operating and encoding processing is executed Set the encoding parameters using the status information. Therefore, the encoding processing unit must be operated even in a camera standby (sleep) state in which actual recording is not performed, and power is wasted.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an imaging apparatus that can set an appropriate encoding parameter in accordance with a use situation and can reduce power consumption.

In order to solve the above problems, a camera unit that captures an image of a subject and outputs a video signal, and the video signal output from the camera unit as a series of moving images, the moving image changes according to the characteristics of the image. An encoding unit that performs compression encoding according to the target code amount, an instruction unit that instructs the start and end of recording of the moving image, and the first moving image by the instruction unit when the first moving image is being recorded in response to the recording end of the image is instructed, an imaging apparatus and a control means for shifting the coded unit while the camera unit and the operating state to a recording pause to the non-operating state, the In response to an instruction to start recording the second moving image by the instruction unit during the recording pause, the control unit makes a transition to a recording mode in which the camera unit and the encoding unit are in an operating state. The encoding , When the camera status information of the camera unit at the recording end of the moving image of those first differences between the camera status information of the camera unit in the recording start time of the second moving image in a predetermined range The encoding of the second moving image is started by setting the target code amount that is continuous between the first moving image and the second moving image .
An imaging apparatus according to the present invention captures a subject and outputs a video signal, and the video signal output from the camera unit as a series of moving images, the moving image changes according to the characteristics of the image. An encoding unit that performs compression encoding according to the target code amount, an instruction unit that instructs the start and end of recording of the moving image , and the first moving image by the instruction unit when the first moving image is being recorded In response to an instruction to end recording of an image, a control means for making a transition to a recording pose in which the encoding unit is in a non-operational state while keeping the camera unit in an operating state, and a control unit immediately before making a transition to the recording pose An encoding parameter holding unit for storing the target code amount used in the encoding of the first moving image, and a transition from the recording pause to a recording mode in which the camera unit and the encoding unit are in an operating state. , Record And an encoding initial parameter setting unit that sets an encoding initial parameter for an elephant moving image, wherein the control unit records the second moving image by the instruction unit during the recording pause. When the start is instructed, the recording mode is shifted to, and the encoding initial parameter setting means includes the camera status information of the camera unit at the end of the recording of the first moving image and the second moving image. If the difference from the camera status information of the camera unit at the start of image recording is within a predetermined range, the target code amount used in the encoding of the first moving image stored in the encoding parameter holding unit and characterized by setting to the encoding initialization parameters for the second video image.
An imaging apparatus according to the present invention captures a subject and outputs a video signal, and the video signal output from the camera unit as a series of moving images, the moving image changes according to the characteristics of the image. An encoding unit that performs compression encoding according to the target code amount, an instruction unit that instructs the start and end of recording of the moving image , and the first moving image by the instruction unit when the first moving image is being recorded. In response to an instruction to finish recording, the control means for making a transition to a recording pause in which the encoding section is in the non-operating state while the camera section is in an operating state, and a measuring means for measuring the period of the recording pause The control unit is configured to detect the camera unit and the encoding unit in response to an instruction to start recording the second moving image by the instruction unit during the recording pause. The operating state To transition to a recording mode in which, the encoding unit for a period of recording pause which is measured by the measuring means when within a predetermined time, continuously between the first moving image and the second moving image The target code amount is set and the encoding process of the second moving image is started .
An imaging apparatus according to the present invention captures a subject and outputs a video signal, and the video signal output from the camera unit as a series of moving images, the moving image changes according to the characteristics of the image. An encoding unit that performs compression encoding according to the target code amount, an instruction unit that instructs the start and end of recording of the moving image , and the first moving image by the instruction unit when the first moving image is being recorded In response to an instruction to end image recording, control means for transitioning to a recording pause in which the encoding unit is inoperative while the camera unit is in an operating state, and measurement for measuring the period of the recording pause Means, an encoding parameter holding unit for storing a target code amount used in encoding of the first moving image immediately before the transition to the recording pause, and the camera unit and the encoding unit from the recording pause Work And an encoding initial parameter setting unit that sets an encoding initial parameter for a moving image to be recorded when the recording mode is shifted to the recording mode. In response to the instruction to start recording the second moving image by the instruction unit, the recording mode is changed to the recording initial parameter setting unit. The encoding initial parameter setting unit has a predetermined recording pause period measured by the measuring unit. If in time, the target code amount that has been used in the encoding of the first moving image stored in the coded parameter holding unit, to be set in the encoding initialization parameters for the second video image It is characterized by.

  According to the present invention, according to the difference between the camera status information at the time of the encoding process before the encoding pause and the camera status information after the encoding pause, or the encoding process before the encoding pause according to the encoding pause period. Therefore, the image quality can be stabilized as compared with the case where the fixed encoding initial parameter that is fixedly determined is used. Further, even if the power supply to the encoding unit is interrupted when the encoding process is not being executed, there is no problem in continuing the encoding, so that power consumption can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an imaging apparatus according to an embodiment of the present invention.

  The camera unit 10 performs a known camera signal process such as gamma correction and color balance adjustment on an image sensor such as a CCD or CMOS type and its output image signal, and a video signal conforming to a predetermined video signal standard, for example, NTSC or a digital signal thereof. The signal is output to the encoding unit 12.

  The encoding unit 12 compresses and encodes the video signal from the camera unit 10 using an MPEG2 compression method using encoding parameters determined and set by a method described later. The compressed and encoded image data is recorded on the recording medium 26. In monitoring applications and the like, compression-encoded image data is transmitted to a remote place and recorded as necessary.

  The camera unit 10 also outputs camera status information at the time of shooting to the encoded initial parameter calculation unit 14. The camera status information includes information indicating the control state of the modules constituting the camera unit 10. For example, it includes at least one of identification information of a lens used, zoom magnification, focal length, subject distance, exposure value, color temperature for color balance adjustment, gamma value, presence / absence of flash, and shooting date / time.

The encoding initial parameter calculation unit 14 calculates the initial parameter of the encoding unit 12 from the camera status information from the camera unit 10 and stores the calculation result in the encoding initial parameter holding unit 16. The encoding initial parameter holding unit 16 that holds the calculation result is composed of, for example, a RAM.

  The encoding initial parameter holding unit 18 composed of ROM holds encoding initial parameters as empirically determined in TM5, and the encoding initial parameters are held when the image pickup apparatus of the present embodiment is manufactured. The data is written in the unit 18.

  The switch 20 or the selector reads the encoding initial parameter stored in the holding unit 16 or the holding unit 18 in accordance with the switch control signal from the control unit 22 and sets it in the encoding unit 12. The switch 20 functions as an encoding initial parameter setting unit that sets an encoding initial parameter in the encoding unit 12.

  The control unit 22 controls the switch 20 according to the operation status of the recording switch 24, specifically, whether the recording is the first recording in the recording mode or the recording after the recording pause. Details of control of the switch 20 by the control unit 22 will be described later.

  When the video signal compressed and encoded by the encoding unit 12 is transmitted to the outside, the recording start and recording end instructions should be understood as encoding start and end instructions, respectively. Similarly, a recording pose should be understood as an encoded pose.

  FIG. 2 shows a schematic block diagram of the encoding unit 12. The apparatus configuration shown in FIG. 2 corresponds to the MPEG system. H.264, those using other compression coding schemes can also be used.

  A video signal (uncompressed image data) from the camera unit 10 is input to the input terminal 30 of the encoding unit 12. The block dividing device 32 divides the video signal from the input terminal 30 into a plurality of blocks, for example, blocks of 8 pixels × 8 pixels or 16 pixels × 16 pixels, in units of screen, and outputs image data in units of blocks. . The size of one block depends on the compression method.

  The subtractor 34 passes through the image data from the block dividing device 32 during intra-screen coding, so-called intra coding. On the other hand, at the time of inter-picture prediction coding, so-called inter coding, the prediction value of the reference image data from the motion compensation device 58 is subtracted from the image data from the block dividing device 32. That is, the subtractor 34 outputs the image data itself at the time of intra coding, and outputs an expected difference value at the time of inter coding.

  A discrete cosine transform (DCT) device 36 performs a discrete cosine transform on the output of the subtractor 34 and outputs the transform coefficient. Depending on the compression method, transform coding other than discrete cosine transform may be used. The quantizer 38 quantizes the transform coefficient from the DCT device 36 based on the quantization scale specified by the code amount control device 46. The variable length coding device 40 performs variable length coding on the transform coefficient quantized by the quantizer 38 according to entropy coding such as Huffman coding. The variable length encoding device 40 also multiplexes a motion vector from the motion detection device 56 described later with the encoded image data and outputs the multiplexed image data to the buffer 42. The buffer 42 sequentially reads the stored data and supplies it to the recording medium 26 via the output terminal 44.

  The code amount control device 46 is supplied from the switch 20 with an encoding initial parameter used at the start of encoding. At the beginning of encoding, the code amount control device 46 sets a quantization scale corresponding to the encoding initial parameter from the switch 20 in the quantizer 38. Thereafter, the code amount control device 46 determines the quantization scale according to the monitoring result of the remaining amount of the buffer 42 so that the buffer 42 does not overflow or underflow by the above-described method such as TM5. The code amount control device 46 sequentially supplies the encoding parameter corresponding to the currently applied quantization scale to the encoding initial parameter calculation unit 14.

  The transform coefficient quantized by the quantizer 38 is also used for generating predicted image data. The inverse quantizer 48 inversely quantizes the output data of the quantizer 38, and the inverse discrete cosine transform (IDCT) device 50 performs inverse discrete cosine transform on the output of the inverse quantizer 48. The output of the IDCT apparatus 50 is locally restored image data (in the case of intra coding) or difference data (in the case of inter coding). The adder 52 passes through the output data of the IDCT device 50 in the case of intra coding, and adds the predicted value to the output data of the IDCT device 50 in the case of inter coding. As a result, inter-coded difference data is restored to image data. The locally decoded image data output from the adder 52 is stored in the frame memory 54 as reference image data for predictive coding. The frame memory 54 can store image data having the number of frames according to the frame range referred to in predictive encoding.

  The motion detection device 56 detects the motion vector of the image from the current image data from the block dividing device 32 and the reference image in the frame memory 54, and the motion compensation device 58 and the variable length encoding device 40 detect the detected motion vector. To supply. The motion compensator 58 refers to the motion vector from the motion detector 56, compensates for the motion of the reference image from the frame memory 54, and supplies it to the subtractor 34 and the adder 52 as predicted values.

  By such an operation, the encoding unit 12 compresses and encodes a series of moving images by using both intra encoding and inter encoding using motion compensation and interframe prediction.

  The characteristic operation of the present embodiment will be described with reference to FIGS. FIG. 3 shows an illustrative example. FIG. 4 shows an example of focusing area division within the photographing field of view. FIG. 5 is a flowchart of the characteristic operation of this embodiment.

The encoding initial parameter calculation unit 14 uses the camera status information from the camera unit 10 and the encoding parameter from the encoding unit 12 at the end of the previous recording, and the camera status information at the start of the current recording. Then, the encoding initial parameter (first encoding initial parameter) of the current recording is calculated. For convenience of explanation, the previous recording is called the (n-1) th recording, where n is the encoded clip number. (N-1) th recording data in recording a clip (n-1), and the camera status information C _n, the coding parameters and E _n. Here are attempting to run a n-th recording, it is denoted the clip and clip n, denoted the camera status information at that time C _n, the encoding parameters and E _n.

  In this example, it is assumed that the camera status information includes focus information and pan / tilt information. The focus information is information indicating an in-focus state, and in this embodiment, the focus information indicates a focus level and a focus position. The focus level is an index used when the imaging apparatus automatically adjusts the photographing lens system to the focus position during autofocus setting. For example, the high-frequency component amount of the image is used. If the high-frequency component increases, the sense of resolution increases and it is determined that the focus level is high. Conversely, if the high-frequency component is reduced, the resolution is lowered and it is determined that the in-focus level is low. As for the in-focus position, as shown in FIG. 4, the image in the field of view is divided into a plurality of areas, and the area with the highest in-focus level is set as the in-focus position.

  Here, the target code amount and the complexity of the image used when determining the target code amount are adopted as the encoding parameters. This corresponds to Xi, Xp, and Xb described in the description of the TM5 system.

  FIG. 3A shows the operating state of the image pickup apparatus of the present embodiment. When the recording mode is set with the mode dial after the power is turned on, or when the power is turned on with the recording mode set with the mode dial (time t1), the recording standby state or the recording pause state for waiting for recording is set. Become. When the recording switch 24 is pressed in the recording standby state (time t2), recording of the clip 0 is started. When the recording switch 24 is pressed again (time t3), recording is stopped and the recording standby state or recording pause state is resumed. When the recording switch 24 is pressed again (time t4), recording of the next clip 1 is started.

3B shows whether the camera unit 10 is in an active state or a sleep state, and FIG. 3C shows whether the encoding unit 12 is in an active state or a sleep state. When in the active state, the camera unit 10 outputs a video signal of a subject to the encoding unit 12 and outputs camera status information to the encoding initial parameter calculation unit 14. In the sleep state, the camera unit 10 outputs neither a video signal nor a camera status signal. In the active state, the encoding unit 12 executes the encoding process of the video signal from the camera unit 10 and outputs the obtained compressed data. Camera unit 10 is in the sleep state, without performing the encoding process, preferably in a power-off state.

  The camera unit 10 is in the active state and the encoding unit 12 is in the sleep state until recording is started after the imaging apparatus is turned on. In a state where recording is finished and the next recording is waited without turning off the power, that is, a so-called recording pause state, the camera unit 10 is in an active state and the encoding unit 12 is in a sleep state (example shown in FIG. 3). Then, the period from time t3 to t4).

  FIG. 3D shows the focus degree of focus information, which is an example of camera status information supplied from the camera unit 10 to the encoding initial parameter calculation unit 14, and FIG. 3E shows the focus area. . In FIG. 3D, the vertical axis represents the focus level. The focus level is higher as it goes up, and the focus level is lower as it goes down.

  The encoding initial parameter calculation unit 14 does not function for the first recording after power-on (that is, the clip number n = 0), but functions for the second and subsequent recordings. In the second and subsequent recordings, more specifically, recording after releasing the recording pause, the difference in focus level is within a predetermined value from the recording before the recording pause, and the focus position does not change. In this case, the encoding parameter applied at the end of the previous recording is used as it is.

  If the difference in focus level from the recording immediately before the recording pause exceeds a predetermined value or the focus position varies, a predetermined calculation is performed from the encoding parameter applied at the end of the previous recording. The encoding parameter obtained in (1) is used. For example, if the focus level at the end of recording immediately before the recording pause is low and the focus level at the start of recording after releasing the recording pause is high, the resolution becomes high and the degree of difficulty in encoding the image increases. Therefore, it is necessary to increase the target code amount. Conversely, if the focus level at the end of recording immediately before the recording pause is high and the focus level at the start of recording after releasing the recording pause is low, the resolution becomes low and the difficulty of encoding the image decreases. . Considering these, the target code amount at the end of recording immediately before the recording pause is multiplied by the ratio of the focus level, and the target code amount at the start of recording after releasing the recording pause is used. Even for this, it is possible to perform appropriate encoding.

  FIG. 5 will be specifically described. When the power is turned on while the recording mode is designated by the mode dial or when the recording mode is designated by the mode dial in the power-on state (time t1), the flow shown in FIG. 5 starts. As an initialization operation, the clip number n is initialized to 0 (S1). A recording standby state in which the recording switch 24 is waited for depression is entered (S2).

  When the recording switch 24 is pressed at time t2 (S3), it is determined whether or not the clip number n is 0 (S4). In the recording immediately after the power is turned on, n is 0, and in the recording after the recording pause, n is 1 or more.

When n is 0 (S4), the control unit 22 selects the encoding initial parameter E _INIT stored in the holding unit 18 in the switch 20 and supplies it to the encoding unit 12. Thereby, the encoding initial parameter stored in the holding unit 18 is set in the code amount control device 46 of the encoding unit 12 (S5). The encoding unit 12 compresses and encodes the video signal from the camera unit 10 using the set encoding initial parameter. The compressed data obtained by the encoding unit 12 is stored in the recording medium 26 as clip 0 (S6).

When the user depresses the recording switch 24 at time t3 (S7), the recording is stopped, and a recording standby state, so-called recording pause state is entered (S8). In this recording pause state, as shown in FIG. 3, the camera unit 10 is in the active state, but the encoding unit 12 is in the sleep state. The encoding initial parameter calculation unit 14 stores the camera status information C ₀ at the end of recording of the clip 0, that is, the focus level and the focus area (S9), and the control unit 22 increments the clip number n. (S10).

  If the recording mode is maintained without turning off the power (S11), the process returns to step S2 to continue the recording standby state (S2). When the power is turned off or the recording mode is canceled with the mode dial, for example, when the mode is changed to the reproduction mode (S11), the flow shown in FIG. 5 ends.

Assume that the user presses the recording switch 24 to instruct to start recording with respect to the second clip (S3). At this time, since n = 1, the process proceeds to step S12. In step S12, the encoding initial parameter calculation unit 14 includes a camera status information C ₀ in the recording end of the clip 0 before recording pause is compared with the current camera status information C _1, the difference is less than the predetermined threshold th It is checked whether or not (S12). If it is less than th, it is further checked whether the in-focus areas are the same (S13). That is, it is checked whether or not there is a substantial change in the subject distance and the position within the angle of view. This corresponds to checking whether or not the same photographing with respect to the same subject is continued.

  When the same shooting is continued in this way (S12, S13), the encoding initial parameter calculation unit 14 stores the encoding initial parameter including the target code amount used in the clip recorded immediately before the recording pause in the holding unit 16. Store. The switch 20 sets the encoding initial parameter held in the holding unit 16 in the encoding unit 12 according to the instruction of the control unit 22 (S14). As a result, the encoding unit 12 can compress and encode the video signal from the camera unit 10 using a substantially continuous target code amount even though the clips are different clips.

Camera status information C ₀ and the camera status information whether the difference between the C ₁ is equal to or greater than the predetermined threshold value th (S12), if the focusing area different (S13), the encoding initial parameter calculation unit 14, according to the focus level Change the target code amount. Then, the encoding initial parameter calculation unit 14 stores the encoding initial parameter including the target code amount in the holding unit 16. The switch 20 sets the encoding initial parameter held in the holding unit 16 in the encoding unit 12 according to the instruction of the control unit 22 (S15). Thereby, an appropriate target code amount according to the resolution of the image can be initially set.

  Although the focus level and focus area, which are focus information, are used as camera status information, one or more of camera shake information, zoom information, and pan / tilt information may be used. Further, the target code amount is used as the initial encoding parameter, but in addition to this, one or more of the bit rate, the fullness necessary for bit rate calculation, the initial quantization scale code, and the initial average value at the time of activity calculation are used. May be. This embodiment can be applied to a case where the general parameters whose initial values are fixed in the TM5 method are adaptively changed.

  FIG. 6 shows a schematic block diagram of the second embodiment of the present invention, and FIG. 7 shows an operation flowchart of the present embodiment. The same components as those in the embodiment shown in FIG. The camera unit 10a is different from the camera unit 10 in that it does not output camera status information. The encoding initial parameter calculation unit 14a is different from the encoding initial parameter calculation unit 14 in that the recording standby time measured by the timer 28 is used instead of the camera status information.

  With reference to FIG. 7, the characteristic operation of the present embodiment will be described. When the power is turned on while the recording mode is designated by the mode dial, or when the recording mode is designated by the mode dial in the power-on state, the flow shown in FIG. 7 starts. As an initialization operation, the clip number n is initialized to 0 (S21). A recording standby state in which the recording switch 24 is waited for pressing is entered (S22).

  When the recording switch 24 is pressed (S23), it is determined whether or not the clip number n is 0 (S24). In the recording immediately after the power is turned on, n is 0, and in the recording after the recording pause, n is 1 or more.

When n is 0 (S24), the control unit 22 selects the encoding initial parameter E _INIT stored in the holding unit 18 in the switch 20 and supplies it to the encoding unit 12. As a result, the encoding initial parameter stored in the holding unit 18 is set in the code amount control device 46 of the encoding unit 12 (S25). The encoding unit 12 compresses and encodes the video signal from the camera unit 10 using the set encoding initial parameter. The compressed data obtained by the encoding unit 12 is stored in the recording medium 26 as clip 0 (S26).

When the user depresses the recording switch 24 again (S27), the recording is stopped and the recording standby state, so-called recording pause state is entered (S28). In this recording pause state, the camera unit 10 is in an active state, but the encoding unit 12 is in a sleep state. Coding initial parameter calculation unit 14a refers to the timer 28, and stores the recording end time _{t n} (S29). The control unit 22 increments the clip number n (S30).

  If the recording mode is maintained without turning off the power (S31), the process returns to step S22, and the recording standby state is maintained (S22). When the power is turned off or the recording mode is canceled with the mode dial, for example, when the mode is changed to the reproduction mode (S31), the flow shown in FIG. 7 ends.

Assume that the user presses the recording switch 24 to instruct to start recording with respect to the second clip (S23). At this time, since n = 1 (S24), the process proceeds to step S32. In step S32, the encoding initial parameter calculation unit 14a refers to the timer 28, measures the immediately preceding recording pause time (t _n −t _n−1 ), and checks whether it is shorter than the predetermined period T _th (S32). ). t _n is the recording start time of clip n, and t _n−1 is the recording end time of clip n−1.

If the immediately preceding recording pause time is shorter than the predetermined period _Tth (S32), it can be assumed that the same shooting for the same subject is continued. At this time, the encoding initial parameter calculation unit 14 a stores the encoding initial parameter including the target code amount used in the clip recorded immediately before the recording pause in the holding unit 16. The switch 20 sets the encoding initial parameter held in the holding unit 16 in the encoding unit 12 according to the instruction of the control unit 22 (S33). As a result, the encoding unit 12 can compress and encode the video signal from the camera unit 10 using a substantially continuous target code amount even though the clips are different clips.

If the immediately preceding recording pause time is equal to or longer than the predetermined period Tth (S32), it can be assumed that the subject or the shooting situation is different. At this time, the control unit 22 controls the switch 20 to set the encoding initial parameter held in the holding unit 18 in the encoding unit 12 (S25). As a result, the encoding unit 12 compresses and encodes the video signal from the camera unit 10 using a target code amount unrelated to the recording before the recording pause.

  FIG. 8 shows a schematic block diagram of a third embodiment of the present invention, and FIG. 9 shows an operation flowchart of the present embodiment. The same components as those in the embodiment shown in FIG. The encoded initial parameter calculation unit 14b differs from the encoded initial parameter calculation units 14 and 14a in that both the camera status information from the camera unit 10 and the recording standby time measured by the timer 28 are used. The third embodiment is a combination of the first and second embodiments.

  With reference to FIG. 9, the characteristic operation of the present embodiment will be described. When the power is turned on while the recording mode is designated by the mode dial, or when the recording mode is designated by the mode dial in the power-on state, the flow shown in FIG. 9 starts. As an initialization operation, the clip number n is initialized to 0 (S41). A recording standby state in which the recording switch 24 is waited for depression is entered (S42).

  When the recording switch 24 is pressed (S43), it is determined whether or not the clip number n is 0 (S44). In the recording immediately after the power is turned on, n is 0, and in the recording after the recording pause, n is 1 or more.

When n is 0 (S44), the control unit 22 selects the encoding initial parameter E _INIT stored in the holding unit 18 in the switch 20 and supplies it to the encoding unit 12. Thereby, the encoding initial parameter stored in the holding unit 18 is set in the code amount control device 46 of the encoding unit 12 (S45). The encoding unit 12 compresses and encodes the video signal from the camera unit 10 using the set encoding initial parameter. The compressed data obtained by the encoding unit 12 is stored in the recording medium 26 as clip 0 (S46).

When the user presses the recording switch 24 again (S47), the recording is stopped and the recording standby state, so-called recording pause state, is entered (S48). In this recording pause state, as shown in FIG. 3, the camera unit 10 is in the active state, but the encoding unit 12 is in the sleep state. The encoding initial parameter calculation unit 14b stores the camera status information C ₀ at the end of recording of the clip 0, that is, the focusing level and the focusing area, and refers to the timer 28 to record the recording end time t of the clip 0. ₀ is stored (S49). The control unit 22 increments the clip number n (S50).

  If the recording mode is maintained without turning off the power (S51), the process returns to step S42, and the recording standby state is maintained (S42). When the power is turned off or the recording mode is canceled with the mode dial, for example, when the mode is changed to the reproduction mode (S51), the flow shown in FIG. 9 ends.

Assume that the user presses the recording switch 24 to instruct the start of recording for the second clip (S43). At this time, since n = 1 (S44), the process proceeds to step S52. In step S52, the encoding initial parameter calculation unit 14b, the camera status information C ₀ in the recording end of the clip 0 before recording pause is compared with the current camera status information C _1, the difference is less than the predetermined threshold th It is checked whether or not (S52). If it is less than th, it is further checked whether the in-focus areas are the same (S53). That is, it is checked whether or not there is a substantial change in the subject distance and the position within the angle of view. This corresponds to checking whether or not the same photographing with respect to the same subject is continued. In this embodiment, when the in-focus areas are the same (S53), it is further checked whether or not the immediately preceding recording pause time is shorter than the predetermined threshold value _Tth (S54). This increases the accuracy of continuing the same shooting for the same subject.

  When the same shooting is continued as described above (S52 to S53), the encoding initial parameter calculation unit 14b stores the encoding initial parameter including the target code amount used in the clip recorded immediately before the recording pause in the holding unit 16. Store. The switch 20 sets the encoding initial parameter held in the holding unit 16 in the encoding unit 12 according to the instruction of the control unit 22 (S55). As a result, the encoding unit 12 can compress and encode the video signal from the camera unit 10 using a substantially continuous target code amount even though the clips are different clips.

Whether the difference between the camera status information C ₀ and the camera status information C ₁ is equal to or greater than the predetermined threshold _th (S52), whether the focus area is different (S53), or the immediately preceding recording pause time is equal to or greater than the predetermined threshold T _th (S54) The encoding initial parameter calculation unit 14b changes the target code amount according to the focus level. Then, the encoding initial parameter calculation unit 14 b stores the encoding initial parameter including the target code amount in the holding unit 16. The switch 20 sets the encoding initial parameter held in the holding unit 16 in the encoding unit 12 according to the instruction of the control unit 22 (S56). Thereby, an appropriate target code amount according to the resolution of the image can be initially set in the encoding unit 12.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

It is a schematic block diagram of Example 1 of the present invention. 3 is a block diagram of a schematic configuration of an encoding unit 12. FIG. It is a schematic diagram of an example of the mode transition and operation | movement of a present Example. It is a schematic diagram which shows the example of a division | segmentation of a focusing area. 3 is an operation flowchart according to the first embodiment. It is a schematic block diagram of Example 2 of this invention. 6 is an operation flowchart of the second embodiment. It is a schematic block diagram of Example 3 of the present invention. 10 is an operation flowchart of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a: Camera part 12: Encoding part 14, 14a, 14b: Encoding initial parameter calculating part 16: Encoding initial parameter holding part 18: Encoding initial parameter holding part 20: Switch 22: Control part 24: Recording switch 30: input terminal 32: block dividing device 34: subtractor 36: discrete cosine transform (DCT) device 38: quantizer 40: variable length coding device 42: buffer 44: output terminal 46: code amount control device 48: inverse Quantizer 50: Inverse discrete cosine transform (IDCT) device 52: Adder 54: Frame memory 56: Motion detection device 58: Motion compensation device

Claims (8)

A camera unit that images a subject and outputs a video signal;
A video signal output from the camera unit as a series of moving images , an encoding unit that compresses and encodes the moving image according to a target code amount that changes according to the characteristics of the image ;
Instruction means for instructing the start and end of recording of the moving image ;
When the first moving image is being recorded, the encoding unit is deactivated while the camera unit is in an operating state in response to an instruction to stop recording the first moving image by the instruction unit. An imaging device comprising: a control means for transitioning to a recording pose to be in a state ;
The control means shifts to a recording mode in which the camera unit and the encoding unit are in an operating state in response to an instruction to start recording of the second moving image by the instruction unit during the recording pause. ,
The encoding unit includes a camera status information of the camera unit at the recording end of the moving image of those first differences between the camera status information of the camera unit in the recording start time of the second moving image given If it is within the range, the target code amount that is continuous between the first moving image and the second moving image is set, and the encoding process of the second moving image is started. Imaging device. The encoding unit has a predetermined difference between the camera status information of the camera unit at the end of recording of the first moving image and the camera status information of the camera unit at the start of recording of the second moving image. When the recording of the first moving image is completed, the target code amount at the end of recording the first moving image is set as an encoding initial parameter for the second moving image , and the encoding process of the second moving image is started. The imaging apparatus according to claim 1. The encoding unit has a predetermined difference between the camera status information of the camera unit at the end of recording of the first moving image and the camera status information of the camera unit at the start of recording of the second moving image. If not, the value obtained by multiplying the target code amount at the end of recording of the first moving image by the ratio of the focus level indicated by the camera status information is the initial encoding for the second moving image. The imaging apparatus according to claim 1, wherein the second moving image encoding process is started by setting the parameter. A camera unit that images a subject and outputs a video signal;
A video signal output from the camera unit as a series of moving images , an encoding unit that compresses and encodes the moving image according to a target code amount that changes according to the characteristics of the image ;
Instruction means for instructing the start and end of recording of the moving image ;
When the first moving image is being recorded, the encoding unit is deactivated while the camera unit is in an operating state in response to an instruction to stop recording the first moving image by the instruction unit. A control means for transitioning to a recording pose to be in a state ;
An encoding parameter holding unit that stores a target code amount used in encoding of the first moving image immediately before the transition to the recording pause ;
Encoding initial parameter setting means for setting an encoding initial parameter for a moving image to be recorded when transitioning from the recording pause to a recording mode in which the camera unit and the encoding unit are in an operating state;
An imaging device comprising:
The control means makes a transition to the recording mode in response to an instruction to start recording the second moving image by the instruction means during the recording pause,
The encoding initial parameter setting means includes a difference between camera status information of the camera unit at the end of recording of the first moving image and camera status information of the camera unit at the start of recording of the second moving image. Is within the predetermined range, the target code amount used in the encoding of the first moving image stored in the encoding parameter holding unit is set as the encoding initial parameter for the second moving image. An imaging apparatus characterized by: A camera unit that images a subject and outputs a video signal;
A video signal output from the camera unit as a series of moving images , an encoding unit that compresses and encodes the moving image according to a target code amount that changes according to the characteristics of the image ;
Instruction means for instructing the start and end of recording of the moving image ;
When the first moving image is being recorded, the encoding unit is deactivated while the camera unit is in an operating state in response to an instruction to stop recording the first moving image by the instruction unit. A control means for transitioning to a recording pose to be in a state;
An imaging device comprising a measuring means for measuring the period of the recording pause ,
The control means shifts to a recording mode in which the camera unit and the encoding unit are in an operating state in response to an instruction to start recording of the second moving image by the instruction unit during the recording pause. ,
The encoding unit sets the target code amount that is continuous between the first moving image and the second moving image when the period of the recording pause measured by the measuring unit is within a predetermined time. And starting the encoding process of the second moving image . When the recording pause period is within a predetermined time, the encoding unit sets a target code amount at the end of recording of the first moving image as an encoding initial parameter for the second moving image , The imaging apparatus according to claim 5, wherein encoding processing of the second moving image is started. When the recording pause period is not within a predetermined time, the encoding unit sets a predetermined target code amount as an encoding initial parameter for the second moving image, and sets the second moving image The imaging apparatus according to claim 5 or 6, wherein an encoding process is started. A camera unit that images a subject and outputs a video signal;
A video signal output from the camera unit as a series of moving images , an encoding unit that compresses and encodes the moving image according to a target code amount that changes according to the characteristics of the image ;
Instruction means for instructing the start and end of recording of the moving image ;
When the first moving image is being recorded, the encoding unit is deactivated while the camera unit is in an operating state in response to an instruction to stop recording the first moving image by the instruction unit. A control means for transitioning to a recording pose to be in a state;
A measuring means for measuring the period of the recording pause ;
An encoding parameter holding unit that stores a target code amount used in encoding of the first moving image immediately before the transition to the recording pause ;
Encoding initial parameter setting means for setting an encoding initial parameter for a moving image to be recorded when transitioning from the recording pause to a recording mode in which the camera unit and the encoding unit are in an operating state;
An imaging device comprising:
The control means makes a transition to the recording mode in response to an instruction to start recording the second moving image by the instruction means during the recording pause,
The encoding initial parameter setting unit is used for encoding the first moving image stored in the encoding parameter holding unit when the recording pause period measured by the measuring unit is within a predetermined time. and the target code amount, the image pickup apparatus characterized by setting to the encoding initialization parameters for the second video image.

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