JP3364396B2 - Distance measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device which targets an object such as an automobile or a human being (target), collates image data based on spatial frequency characteristics, and measures the distance from the collation result to the target. It is a thing.

[0002]

Conventionally, as this kind of distance measuring device, by imaging a target with two cameras, set the window portion that is reflected the target in one of the images, the window in the other image Whether there is a part that matches the image 1
While shifting pixel by pixel, a search is made for a place where the sum of the absolute values of the differences between the pixels is minimized, and the distance between the corresponding images is detected as a shift between the images picked up by the two cameras. There is a device that measures distance.

[0003]

However, in such a conventional distance measuring device, it takes a long time to obtain the image shift. In addition, it is necessary to set the window , which complicates the process. Also, since I use two cameras,
High cost.

The present invention has been made to solve such a problem, and an object thereof is to easily measure a distance to a target in a short time and at a low cost. To provide.

[0005]

In order to achieve such an object, in the first invention (the invention according to claim 1), the target is viewed from the first direction and the image viewed from the second direction. The image is guided to the image pickup unit of one camera, and the image data of the target seen from the first direction guided to the image pickup unit of this camera is used as the first pattern data, and the first pattern data is two-dimensionally discrete. The first Fourier two-dimensional pattern data is created by subjecting the image data obtained by viewing the target from the second direction guided by the image pickup unit of this camera to the second pattern data. The two-dimensional discrete Fourier transform is applied to the pattern data of to create second Fourier two-dimensional pattern data, and the first Fourier two-dimensional pattern data and the second Fourier two-dimensional pattern data are combined,
One of two-dimensional discrete Fourier transform and two-dimensional discrete inverse Fourier transform is applied to the synthetic Fourier two-dimensional pattern data obtained by this, and thereby the correlation appearing in the Fourier-transformed synthetic Fourier two-dimensional pattern data. The correlation peak is obtained in a range excluding the vicinity of the reference position of the component area, and the distance to the target is measured based on the distance between the reference position of the correlation component area and the position of the correlation peak.

According to the present invention, the image of the target viewed from the first direction and the image of the target viewed from the second direction are guided to the image pickup section of one camera. Then, the image data in which the target is viewed from the first direction guided by the image pickup unit of this camera is set as the first pattern data, and the first pattern data is subjected to the two-dimensional discrete Fourier transform to obtain the first pattern data. Fourier two-dimensional pattern data of is created. Also. The image data of the target viewed from the second direction guided to the image pickup section of the camera is used as the second pattern data, and the second pattern data is subjected to the two-dimensional discrete Fourier transform to generate the second Fourier data. Two-dimensional pattern data is created. Then, the first Fourier two-dimensional pattern data and the second Fourier two-dimensional pattern data are combined, and the combined Fourier two-dimensional pattern data is subjected to a two-dimensional discrete Fourier transform or a two-dimensional discrete inverse Fourier transform, As a result, a correlation peak is obtained in a range excluding the vicinity of the reference position of the correlation component area appearing in the Fourier-transformed synthetic Fourier two-dimensional pattern data. Based on this, the distance to the target is measured.

The second invention (the invention according to claim 2) is the first
In the present invention, the first Fourier two-dimensional pattern data and the second Fourier two-dimensional pattern data are combined, and the combined Fourier two-dimensional pattern data thus obtained is subjected to amplitude suppression processing and then the two-dimensional discrete Fourier transform and One of the two-dimensional discrete inverse Fourier transforms is applied. Third invention (invention according to claim 3)
In the first invention, the image data of the target viewed from the first direction is used as the first pattern data, the two-dimensional discrete Fourier transform is applied to the first pattern data, and then the amplitude suppression processing is performed. First Fourier two-dimensional pattern data is created, image data of the target viewed from the second direction is used as second pattern data, and the second pattern data is subjected to two-dimensional discrete Fourier transform and then amplitude suppression is performed. By performing the processing, the second Fourier two-dimensional pattern data is created. A fourth invention (the invention according to claim 4) is the first to third inventions, wherein the camera is a pinhole camera.

[0008]

[Embodiment 1: Individual image capturing method (first, second and third inventions)]

(Embodiment 1-1) FIG. 2 is a block configuration diagram of a distance measuring device showing an embodiment of the invention. In the figure, 10 is a CCD camera, 20 is a processing unit, 30 is an image capturing unit, and the processing unit 2
0 is a control unit 20-1 having a CPU and a ROM 2
0-2, RAM 20-3, hard disk (HD)
20-4, a frame memory (FM) 20-5 , an external connection unit (I / F) 20-6, and a Fourier transform unit (FF).
T) 20-7, and the ROM 20-2 stores a distance measuring program (FIG. 3). The image capturing section 30 includes a double-sided mirror 30-1 that is rotatably provided on the optical axis of the front surface of the lens 10-1 of the CCD camera 10 about the support axis P1, and the double-sided mirror 30-1. The single-sided mirrors 30-2 and 30-3 are fixedly provided on both sides at a predetermined inclination angle.

In this distance measuring device, when the target is M1, the distance R to the target M1 is measured as follows. First, when the measurement is started, the rotation angle position of the mirror 30-1 is manually changed to the position indicated by the solid line in the figure, that is, the center of the target M1 reflected on the mirror 30-2 is C.
It is set to a position that can be captured by the image pickup unit of the CD camera 10.

In this state, the control unit 20-1 sets an image (image viewed from the first direction) of the target M1 from the CCD camera 10 as an image, and image data O _{1 of} this image.
Are fetched through the frame memory 20-5 (step 301 shown in FIG. 3). Then, the captured image data O ₁ is used as registered image data (FIG. 1A), the registered image data is sent to the Fourier transform unit 20-7, and the registered image data is subjected to two-dimensional discrete Fourier transform (DFT). (Step 302). As a result, the registered image data O ₁ shown in FIG. 1A becomes Fourier image data (registered Fourier image data) F ₁ .

The two-dimensional discrete Fourier transform is described, for example, in "Introduction to Computer Image Processing, edited by Japan Industrial Technology Center, published by Soken Shuppan Co., Ltd., P.44-45 (Reference 1)". .

Next, the rotation angle position of the mirror 30-1 is manually set to the position shown by the dotted line in the figure. That is, the position is symmetrical with respect to the position indicated by the solid line in the figure with the optical axis of the CCD camera 10 as the center. As a result, the center of the target M1 reflected on the mirror 30-3 is at a position opposite to the above, and the CCD camera 10
Is captured by the image pickup section of.

In this state, the control unit 20-1 sets the image (image viewed from the second direction) of the target M1 from the CCD camera 10 as an image, and the image data O _{2 of} this image.
Is fetched through the frame memory 20-5 (step 303). Then, the captured image data O ₂ is used as collation image data (FIG. 1B), this collation image data is sent to the Fourier transform unit 20-7, and this collation image data is subjected to a two-dimensional discrete Fourier transform (DFT). (Step 304). As a result, the collation image data O ₂ shown in FIG. 1B becomes Fourier image data (collation Fourier image data) F ₂ .

The control unit 20-1 then proceeds to step 30.
The Fourier image data (registered Fourier image data) F ₁ obtained in ₂ and the Fourier image data (matching Fourier image data) F ₂ obtained in step 304 are combined (step 305) to obtain combined Fourier image data.

Here, in the composite Fourier image data, when the matching Fourier image data is A · e ^j θ and the registered Fourier image data is B · e ^j φ, A · B · e ^{j (} θ ⁻ φ ⁾
It is represented by. However, A, B, θ, and φ are functions of frequency (Fourier) space (u, v).

And A ・ B ・ e^{j (}θ^-φ⁾Is   A ・ B ・ e^{j (}θ^-φ⁾= A ・ B ・ cos (θ-φ) + j ・ A ・ B ・ sin (θ- φ) ・ ・ ・ (1) Is represented as^jθ = α₁+ Jβ₁, Be^jφ =
α₂+ Jβ₂Then, A = (α₁ ²+ Β₁ ²)^1/2, B =
(Α₂ ²+ Β₂ ²)^1/2, Θ = tan^-1(Β₁/ Α₁ ), Φ =
tan^-1(Β₂/ Α₂). Calculate this formula (1)
By doing so, synthetic Fourier image data is obtained.

Note that A · B · e ^{j (} θ ⁻ φ ⁾ = A · B · e ^j
θ ・ e ^-j φ = A ・ e ^j θ ・ B ・ e ^-j φ = (α ₁ + j
β ₁ ) · (α ₂ −jβ ₂ ) = (α ₁ · α ₂ + β ₁ ·
The combined Fourier image data may be obtained as β ₂ ) + j (α ₂ · β ₁ −α ₁ · β ₂ ).

Then, the control section 20-1 performs the amplitude suppression processing after obtaining the synthetic Fourier image data in this way (step 306). In this embodiment, log processing is performed as the amplitude suppression processing. That is, A · B · e ^{j (} θ ⁻ which is an arithmetic expression of the composite Fourier image data described above.
taking the log of ^{φ), log (A · B} ) · e j (θ - φ) and by the A · B is the amplitude log (A · B)
(A / B> log (A / B)).

In the case of the synthetic Fourier image data subjected to the amplitude suppressing process, the influence of the illuminance difference at the time of collecting the registered image data and the time of collecting the collation image data is small. That is, by performing the amplitude suppression process, the spectrum intensity of each pixel is suppressed, the skipped value is eliminated, and more information becomes effective.

In this embodiment, the log process is performed as the amplitude suppressing process, but the square process may be performed. Further, not limited to log processing and √ processing,
Any process may be used as long as the amplitude can be suppressed. If all the amplitudes are set to 1, for example, only the phase by the amplitude suppression, that is, there is an advantage that the amount of calculation can be reduced and an amount of data is reduced as compared with the log processing and the √ processing.

After performing the amplitude suppression processing in step 306, the control unit 20-1 sends the combined Fourier image data subjected to the amplitude suppression processing to the Fourier transform unit 20-7,
A second two-dimensional discrete Fourier transform (DFT) is performed (step 307).

Then, the control section 20-1 takes in the DFT-applied composite Fourier image data and correlates each pixel in a predetermined correlation component area (all areas in this embodiment) from the composite Fourier image data. The intensity (amplitude) of the component is scanned, the histogram of the intensity of the correlation component of each pixel is obtained, and the pixel with the highest intensity of the correlation component (correlation peak) is extracted from this histogram except the vicinity of the center of the correlation component area. (Step 308) Then, the coordinates of the extracted correlation peak are obtained (Step 309).

The coordinate position of the correlation peak at this time is shown in FIG.
It shows in (c). P _a1 shown in the figure is the position of the correlation peak, and P ₀ is the center of the correlation component area. In this case, the correlation peak P _a1 indicates the target M1, and the distance from the center P ₀ of the correlation component area to the position P _{a1 of the} correlation peak is the deviation A (A = Δa + Δb) between the _two image data O ₁ and O _2. Show. A correlation peak indicating the background appears near the center P ₀ of the correlation component area.

The control unit 20-1 obtains the deviation A between the image data O ₁ and O ₂ from the coordinate position of the correlation peak P _a1 (step 310), and based on the obtained deviation A, the following based on the principle of triangulation: From equation (2), the distance R to the target M1
Is calculated (step 311). Then, the obtained distance R to the target M1 is output to the outside via the I / F 20-6 (step 312). In the following formula (2), f is the distance from the center of the lens 10-1 to the image pickup position, L is the CCD camera 10 and the two CCD cameras 11-.
It is the inter-lens distance when replaced with 1, 11-2. R = f ・ L / A ・ ・ ・ ・ (2)

As described above, according to the distance measuring apparatus of this embodiment, the image data of the target M1 viewed from the first direction and the image data of the target M1 viewed from the second direction are based on the spatial frequency characteristics. Since the collation is performed and the distance to the target M1 is obtained as a result of the collation, the process is simpler than the conventional method, and the distance to the target can be measured in a short time. Moreover, since the measurement can be performed with one camera, the cost can be reduced.

Although the two-dimensional discrete Fourier transform is performed in the Fourier transform unit 20-7 in this embodiment, it may be performed in the CPU 20-1. In this embodiment, the two-dimensional discrete Fourier transform is performed in step 307 shown in FIG. 3, but the two-dimensional discrete inverse Fourier transform is performed instead of the two-dimensional discrete Fourier transform. Good. That is, 2 is applied to the synthetic Fourier image data that has been subjected to the amplitude suppression processing.
Instead of performing the two-dimensional discrete Fourier transform, the two-dimensional discrete inverse Fourier transform may be performed. The two-dimensional discrete Fourier transform and the two-dimensional discrete inverse Fourier transform do not change quantitatively in terms of matching accuracy. The two-dimensional discrete inverse Fourier transform is described in the above-mentioned reference 1.

Further, in this embodiment, amplitude suppression processing is performed on the combined Fourier image data to perform two-dimensional discrete Fourier transform (step 30).
6, 307), the registered Fourier image data and the matching Fourier image data before the synthesis may be subjected to amplitude suppression processing and then synthesized. That is, FIG.
As shown in (a) and (b), step 3 of FIG. 3 is eliminated, and amplitude suppression processing is performed between steps 302 and 303 and between steps 304 and 305.
13-1 and 313-2 may be provided. Alternatively, FIG.
As shown in (c), step 306 in FIG. 3 is eliminated,
A step 313 may be provided between steps 304 and 305 to individually perform amplitude suppression processing on the images O ₁ and O ₂ .

In this case, the amplitude suppression processing in step 313 obtains the registered Fourier image data and the matching Fourier image data that have been subjected to the amplitude suppression processing, and these Fourier image data are combined to form the combined Fourier image data. can get.

The suppression rate of the amplitude of the synthetic Fourier image data at this time is smaller than that in the case where the amplitude suppression processing is performed after the synthetic Fourier image data (FIG. 3). Therefore,
Performing the amplitude suppression processing after the composite Fourier image data (FIG. 3) improves the matching accuracy as compared with the method of performing the amplitude suppression processing and then the composite Fourier image data (FIG. 4). In addition, when performing synthetic | combination Fourier image data after performing an amplitude suppression process (FIG. 4), it is necessary to perform not a two-dimensional discrete Fourier transform but two-dimensional discrete inverse Fourier transform with respect to a synthetic Fourier image data. May be. Further, although the amplitude suppression process is performed in this embodiment, the amplitude suppression process may not necessarily be performed.

Further, in this embodiment, the image data O ₁ viewed from the first direction is the registered image data, and the image data O ₂ viewed from the second direction is the verification image data. The distance from the center of the correlation component area to the position of the correlation peak was determined as the displacement A of the two images, but the image data O ₁ viewed from the first direction was obtained.
Is used as the collation image data and the image data O ₂ viewed from the second direction is used as the registered image data, the shift A between the two images can be obtained in the same manner.

In this case, FIG. 1 corresponds to FIG.
(D) is obtained. That is, the correlation peak P _a1 ′ appears at the opposite position with respect to the center P _{0 of the} correlation area with _respect to the correlation peak P _a1 in FIG. Therefore,
In this case, the distance from the position of the correlation peak P _a1 'to the center P ₀ of the correlation component area is obtained as the shift A between the two images.

(Embodiment 1-2) Embodiment 1-1
In FIG. 2, the mirrors 30-2 and 30-3 are replaced by the mirror 30.
-1, which is provided on both sides of -1, but as shown in FIG.
0 ′ may be rotated 180 ° about the optical axis of the CCD camera 10. In this case, Embodiment 1-
The mirror 30-3 used in 1 can be omitted, and the mirror 30-1 may be a single-sided mirror.

(Embodiment 1-3) Embodiment 1-2
In FIG. 5, the cylindrical body 30 'is rotated by 180 °, but if it is configured as shown in FIG. 6, it is not necessary to rotate by 180 °. That is, in this embodiment,
A half mirror 30-1 'is used in place of the mirror 30-1, and a mask 30-4 which is slidable in the direction of the arrow in the drawing is provided on the front surface of the half mirror 30-1'. In this case, mask 3
Move 0-4 to capture images and images. However,
In this case, the image capturing path is longer than the image capturing path, that is, the image is captured smaller than the image.
Perform the processing after 04 to obtain the shift A between the two images,
The distance R from this deviation A to the target M1 is obtained by the above equation (2).

[Second Embodiment: Simultaneous Image Capture Method (First
Invention, Second Invention, Third Invention)] The first embodiment is suitable when the target is stationary. That is, the first embodiment
Then, because it is an image individual capture method, the timing at which the image and the image are captured is different and the target moves,
When the imaging environment changes from moment to moment, the distance to the target cannot be accurately measured. On the other hand, in the second embodiment to be described below, in order to use the image simultaneous capture method, that is, in order to make the image and the image capturing timing simultaneous, even if the target is moving, Even if changes from moment to moment, it is possible to measure the distance. (Embodiment 2-1) FIG. 7 shows an essential part of this embodiment. In this embodiment, the double-sided mirror 30 shown in FIG.
Instead of -1, a V-shaped single-sided mirror 30-4 is used. In this case, the image and the image are simultaneously captured by the CCD camera 10. That is, the image of the target M1 reflected on the mirror 30-2 (the image viewed from the first direction) and the image of the target M1 reflected on the mirror 30-3 (the image viewed from the second direction) are V-shaped. By the mirror 30-4 of
It is captured redundantly in the image pickup section of the CCD camera 10.

The control unit 20-1 takes in the image data O in which the images from the CCD camera 10 overlap with each other via the frame memory 20-5 (step 801 shown in FIG. 8). Then, a mask process is performed on an area of the captured image data O excluding the image (step 802), and the image data after the mask process is set as the registered image data (FIG. 1A). The registered image data is sent to the Fourier transform unit 20-7, and the registered image data is subjected to two-dimensional discrete Fourier transform (DFT) (step 803). As a result, the registered image data O ₁ becomes Fourier image data (registered Fourier image data) F ₁ .

Next, the control section 20-1 carries out step 801.
A mask process is performed on the area excluding the image in the image data O captured in step S804, and the image data after the mask process is used as the collation image data (FIG. 1B). Fourier transform unit 20 for image data
Then, the collation image data is subjected to two-dimensional discrete Fourier transform (DFT) (step 805). As a result, the matching image data O ₂ becomes Fourier image data (matching Fourier image data) F ₂ .

Then, the control section 20-1 proceeds to step 80.
The Fourier image data (registered Fourier image data) F ₁ obtained in 3 and the Fourier image data (matching Fourier image data) F ₂ obtained in step 805 are combined (step 806) to obtain combined Fourier image data. Then, after performing the amplitude suppression processing on this synthetic Fourier image data,
A second two-dimensional discrete Fourier transform (DFT) is applied to the synthetic Fourier image data that has undergone the amplitude suppression processing (step 808).

Then, the control section 20-1 takes in the DFT-applied composite Fourier image data and correlates each pixel in a predetermined correlation component area (all areas in this embodiment) from the composite Fourier image data. The intensity (amplitude) of the component is scanned, the histogram of the intensity of the correlation component of each pixel is obtained, and the pixel with the highest intensity of the correlation component (correlation peak) is extracted from this histogram except the vicinity of the center of the correlation component area. (Step 809) Then, the coordinates of the extracted correlation peak are obtained (step 810).

The coordinate position of the correlation peak at this time is shown in FIG.
It shows in (c). P _a1 shown in the figure is the position of the correlation peak, and P ₀ is the center of the correlation component area. In this case, the correlation peak P _a1 indicates the target M1, and the distance from the center P ₀ of the correlation component area to the position P _{a1 of the} correlation peak is the deviation A (A = Δa + Δb) between the _two image data O ₁ and O _2. Show. A correlation peak indicating the background appears near the center P ₀ of the correlation component area.

The control unit 20-1 obtains the deviation A between the image data O ₁ and O ₂ from the coordinate position of the correlation peak P _a1 (step 811), and based on the obtained deviation A, the triangulation principle is used. From equation (2), the distance R to the target M1
Is calculated (step 812). Then, the obtained distance R to the target M1 is output to the outside via the I / F 20-6 (step 813).

(Embodiment 2-2) Embodiment 2-1
In FIG. 7, a V-shaped mirror 30-4 and a plane mirror 30-
2, 30-3 were used. On the other hand, Embodiment 2-2
Then, as shown in FIG. 9, spherical mirrors 30-2 ', 30-
3'and 30-4 'are used. In this case, the image is designed and arranged so that the image can be captured by the image pickup unit of the CCD camera 10 when the target M1 is separated by the distance R2 or more. According to this embodiment, the measurable range is wider than in Embodiment 2-1.

(Embodiment 2-3) Embodiment 2-1
In FIG. 7, a V-shaped mirror 30-4 is used. In this case, the lateral width of the image captured by the CCD camera 10 is small, and improvement in accuracy cannot be expected. Therefore, in this embodiment, as shown in FIG.
Place 0-6 crossing. That is, the mirror 30-5
In the upper row and the mirror 30-6 in the lower row so as to intersect. The mirror 30-2 is arranged in the upper stage corresponding to the mirror 30-5, and the mirror 30-3 is arranged in the lower stage corresponding to the mirror 30-6. With such a configuration, the target M1 is individually reflected on the mirrors 30-5 and 30-6, and an overlapping image of the images is captured by the imaging unit of the CCD camera 10. In this case, the width of the image can be made larger than that of the V-shaped mirror 30-4, so that the accuracy is improved.

[Third Embodiment (Fourth Invention)] In the above-described first and second embodiments, the camera 10 is controlled by CC.
Although the D camera is used, this camera may be a camera with a lens or a pinhole camera (without a lens).
A camera with a lens can capture a brighter image than a pinhole camera, but has a demerit that the image is easily distorted.

In the embodiment described above, FIG.
Although the entire area of the synthetic Fourier image data is set as the correlation component area in (c), a partial area may be set as the correlation component area. In this case, the position where the correlation peak indicating the background appears differs depending on how the correlation component area is taken. Therefore, in this case, the position where the correlation peak indicating this background will appear is set as the reference position, and the correlation peak is extracted in a range excluding the vicinity of the reference position.

[0045]

As is apparent from the above description, according to the present invention, the image of the target viewed from the first direction and the image of the target viewed from the second direction are guided to the image pickup section of one camera. The image data in which the target is viewed from the first direction and the image data in which the target is viewed from the second direction are collated based on the spatial frequency characteristic, and the difference between the two images is obtained as the collation result. Therefore, the distance to the target can be easily measured in a short time and at low cost.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a distance measuring process in the distance measuring device shown in FIG.

FIG. 2 shows an embodiment of the present invention (Embodiment 1-
It is a block block diagram of the distance measuring device which shows 1).

FIG. 3 is a flowchart for explaining a distance measurement processing operation in this distance measurement device.

FIG. 4 is a flow chart for explaining another example of the distance measurement processing operation in this distance measurement device.

FIG. 5 shows another embodiment of the present invention (Embodiment 1-
It is a figure which shows the principal part of 2).

FIG. 6 shows another embodiment of the present invention (Embodiment 1)
It is a figure which shows the principal part of 3).

FIG. 7 shows another embodiment of the present invention (Embodiment 2)
It is a figure which shows the principal part of 1).

FIG. 8 is a flowchart for explaining a distance measurement processing operation in this distance measurement device.

FIG. 9 shows another embodiment (Embodiment 2) of the present invention.
It is a figure which shows the principal part of 2).

FIG. 10 shows another embodiment (Embodiment 2) of the present invention.
It is a figure which shows the principal part of -3).

[Explanation of symbols]

10 ... CCD camera, 10-1 ... Lens, 20 ... Processing unit, 20-1 ... Control unit, 20-2 ... ROM, 20-3 ...
RAM, 20-4 ... Hard disk (HD), 20-5
... Frame memory (FM), 20-6 ... External connection part (I
/ F), 20-7 ... Fourier transform unit (FFT), 30 ...
Image capturing unit, 30-1 ... Double-sided mirror, 30-2, 30-
3 ... Single-sided mirror.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-100589 (JP, A) JP-A-60-125515 (JP, A) JP-A-7-248212 (JP, A) JP-A-5- 159056 (JP, A) Koji Kobayashi 4 others, Principle of phase-only correlation method and its application, Television Engineering Society Technical Report, July 16, 1996, Vol. 20, No. 40, pp. 1-6 (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06T ⁷ /00-7/60 G01B 11/00 G06T 1/00 H04N 7/18 JISST file (JOIS)

Claims (4)

(57) [Claims] 1. A camera, an image capturing unit that guides an image of a target viewed from a first direction and an image of a target viewed from a second direction to an image capturing unit of the camera, and an image capturing unit of the camera. Image data in which the target is viewed from the derived first direction is set as first pattern data, and the first pattern two-dimensional discrete Fourier transform is performed on the first pattern data to create first Fourier two-dimensional pattern data. The Fourier pattern data creating means of No. 1 and the image data of the target viewed from the second direction guided by the image pickup unit of the camera are used as the second pattern data, and the second pattern data is subjected to the two-dimensional discrete Fourier transform. Second Fourier pattern data creating means for creating a second Fourier two-dimensional pattern data, the first Fourier two-dimensional pattern data and the second Fourier two-dimensional pattern And a pattern processing means for performing one of the two-dimensional discrete Fourier transform and the two-dimensional discrete inverse Fourier transform on the synthetic Fourier two-dimensional pattern data obtained thereby, and the Fourier transform by the pattern processing means. Correlation peaks are obtained in a range excluding the vicinity of the reference position of the correlation component area appearing in the combined Fourier two-dimensional pattern data subjected to
A distance measuring device comprising distance measuring means for measuring the distance to the target based on the distance between the reference position of the correlation component area and the position of the correlation peak. 2. The pattern processing means according to claim 1, wherein the first Fourier two-dimensional pattern data and the second Fourier two-dimensional pattern data are combined, and the resultant composite two-dimensional pattern data is obtained. A distance measuring device characterized by performing amplitude suppression processing on and performing either one of a two-dimensional discrete Fourier transform and a two-dimensional discrete inverse Fourier transform. 3. The first Fourier pattern data creating means according to claim 1, wherein the image data of the target guided to the imaging section of the camera viewed from the first direction is the first pattern data, This first pattern data is subjected to a two-dimensional discrete Fourier transform, and then amplitude suppression processing is performed to create first Fourier two-dimensional pattern data. Image data obtained by viewing the target guided to the imaging unit from the second direction is used as second pattern data, and the second pattern data is subjected to a two-dimensional discrete Fourier transform and then subjected to amplitude suppression processing. 2. A distance measuring device characterized by creating two Fourier two-dimensional pattern data. 4. The distance measuring device according to claim 1, wherein the camera is a pinhole camera.