Imaging device

Abstract

The present invention addresses the problem of providing an imaging device capable of accurately correcting parallax shift during travel. This imaging device (10) captures an image of a first object (21) and a second object (22) of a preceding vehicle (200), and corrects a parallax shift. The imaging device (10) is provided with: a first imaging unit (11); a second imaging unit (12); a first parallax calculation unit (13) that calculates a first parallax on the basis of an image of the first object captured by the first imaging unit and an image of the first object captured by the second imaging unit; a second parallax calculation unit (14) that calculates a second parallax on the basis of an image of the first object captured by the first imaging unit and an image of the second object captured by the second imaging unit; a virtual baseline length calculation unit (15) that calculates a virtual baseline length using the first parallax, the second parallax, and the baseline length; and a correction unit (16) that corrects the parallax shift on the basis of the virtual baseline length.

Description

Technical Field

[0001] This invention relates to a camera device. Background Technology

[0002] Patent Document 1 describes the following: "An image processing apparatus that identifies the three-dimensional position information of a subject based on a pair of image data obtained by capturing the direction of travel of a vehicle using a stereo camera. The image processing apparatus includes: a vehicle detection processing unit 1d that detects the position of a pair of brake lights on the pair of image data; and a parallax offset value correction processing unit 1e that performs a calculation formula to correct the distance to the subject based on the parallax of the brake lights at two locations with different distances in the direction of travel and the number of pixels between the left and right pairs of brake lights."

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-009388 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] If parallax correction technology using stereo cameras is applied in emerging countries such as Southeast Asia, the technology may not be fully effective in correcting parallax shifts while driving due to poor road conditions. Previous parallax correction technologies utilized the presence of white lines on both sides of the road and the illuminated brake lights (BL) of the vehicle ahead; however, this information is not fully utilized in the road conditions or congested driving environments of Asia.

[0008] The present invention was made in view of the above-mentioned problems, and its object is to provide a camera device that can correctly correct parallax shift while driving.

[0009] Methods for solving problems

[0010] The imaging device of the present invention, which solves the above-mentioned problems, captures images of the first object and the second object from positions equidistant from each other, and corrects for parallax shift. It is characterized by comprising:

[0011] First Camera Department;

[0012] The second camera unit is arranged in pair with the first camera unit at a certain distance away in a direction intersecting the direction toward the object;

[0013] The first parallax calculation unit calculates the first parallax of the first object based on the position of the first object in the image captured by the first camera unit and the position of the first object in the image captured by the second camera unit;

[0014] The second parallax calculation unit calculates a second parallax as the parallax between the first object and the second object based on the position of the first object in the image captured by the first camera unit and the position of the second object in the image captured by the second camera unit;

[0015] The hypothetical baseline length calculation unit calculates a hypothetical baseline length using the first parallax, the second parallax, and a baseline length that is the distance between the first camera unit and the second camera unit. The hypothetical baseline length is the length obtained by adding the baseline length to the distance between the first object and the second object.

[0016] The correction unit corrects the parallax offset between the first camera unit and the second camera unit based on the hypothetical baseline length.

[0017] The effects of the invention

[0018] According to the present invention, a camera device capable of correctly correcting parallax shift during driving can be obtained.

[0019] Other features related to the present invention will become apparent from the description and accompanying drawings in this specification. Furthermore, issues, configurations, and effects other than those described above will become clear from the following description of embodiments. Attached Figure Description

[0020] Figure 1 This is a functional block diagram of the camera device according to the first embodiment of the present invention.

[0021] Figure 2 A flowchart illustrating the parallax offset correction method of the camera device according to the first embodiment.

[0022] Figure 3 This is a diagram illustrating the first parallax.

[0023] Figure 4 This is a diagram illustrating the second parallax.

[0024] Figure 5 It is a diagram illustrating the ranging principle of a stereo camera and the length of the imaginary baseline.

[0025] Figure 6 This is a schematic diagram illustrating an example of a camera device mounted on a vehicle.

[0026] Figure 7It is a diagram showing the positional relationship between the vehicle and the vehicle in front at the first and second shooting times.

[0027] Figure 8 This is a flowchart illustrating the parallax offset correction method of the camera device according to the second embodiment.

[0028] Figure 9 This is a flowchart illustrating the parallax offset correction method of the camera device according to the second embodiment.

[0029] Figure 10 This is a flowchart illustrating the parallax offset correction method of the camera device according to the second embodiment.

[0030] Figure 11 This is a diagram illustrating the method for calculating the number of pixels corresponding to the baseline length in the camera device of the second embodiment.

[0031] Figure 12 A diagram illustrating the method for calculating the distance between the left and right rear tires of the vehicle in front in the camera device of the second embodiment. Detailed Implementation

[0032] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0033] [First Implementation Method]

[0034] Figure 1 This is a functional block diagram of the camera device according to the first embodiment of the present invention. Figure 6 This is a schematic diagram illustrating an example of a camera device mounted on a vehicle.

[0035] like Figure 1 As shown, the camera device 10 includes a camera unit 10a and a control unit 10b that processes images captured by the camera unit 10a. Figure 6 As shown, the camera device 10 is mounted on a vehicle 100 (hereinafter also referred to as the vehicle 100). The camera device 10 is a stereo camera that captures images of the front of the vehicle through the windshield, and has a pair of left and right camera units 11 and 12 as camera units 10a. The pair of left and right camera units 11 and 12 are arranged separately in the vehicle width direction, and can capture images of overlapping areas in front of the vehicle 100, as well as images of objects such as a preceding vehicle 200 traveling in the same direction in front of the vehicle.

[0036] In this embodiment, the first camera 11 of the pair of left and right cameras 11 and 12 is positioned at the center in the vehicle width direction. The second camera 12 is positioned in a direction intersecting the direction toward the object, specifically at a position a certain distance away from the first camera 11 to the left in the vehicle width direction.

[0037] The control unit 10b of the camera device 10 performs image processing on images captured by the left and right pairs of cameras 11 and 12 respectively, and performs object detection and object type recognition. The information from the results of object detection and object type recognition is used in the AD (autonomous driving) and ADAS (advanced driver assistance system) of the vehicle 100.

[0038] Furthermore, the control unit 10b of the imaging device 10 corrects for parallax shift during operation. Parallax shift refers to parallax error, such as that caused by the offset of the optical axes of the left and right imaging units 11 and 12. The control unit 10b of the imaging device 10 captures images of the first and second objects at positions equidistant from each other, and corrects for the parallax shift of the left and right imaging units 11 and 12. The correction of parallax shift is performed using control processing within the control unit 10b that controls the correction value.

[0039] The camera device 10 captures images of the vehicle 200 as an object, and captures images of the left and right rear tires 21 and 22 of the vehicle 200 as a first and a second object, respectively, and corrects for parallax shift. The left and right rear tires 21 and 22 of the vehicle 200 are considered to be objects located at an equal distance from the vehicle 100. In this embodiment, the camera device 10 captures images of the same vehicle 200 twice with a time difference, and corrects for parallax shift based on this difference.

[0040] The control unit 10b of the camera device 10 has an electronic control unit (ECU) that includes a central processing unit (CPU), a storage unit (RAM or ROM), and an input / output unit (I / O interface). Various functions are achieved by reading a dedicated software program installed in the storage device and executing it in the central processing unit. Internally, the control unit 10b includes a first parallax calculation unit 13, a second parallax calculation unit 14, a hypothetical baseline length calculation unit 15, and a correction unit 16.

[0041] The first disparity calculation unit 13 calculates the first disparity w1[pix] of the first object based on the position of the first object in the image captured by the first camera unit 11 and the position of the first object in the image captured by the second camera unit 12. For example, the first disparity calculation unit 13 uses the image captured by the first camera unit 11 as a reference image and the image captured by the second camera unit 12 as a reference image, and calculates the first disparity w1[pix] of the first object by template matching.

[0042] Figure 3 This is a diagram illustrating the first parallax. For example... Figure 3 As shown in (1), when the camera device 10 takes pictures of the vehicle 200 in front through the first camera unit 11 and the second camera unit 12, Figure 3 The image 31 of the first camera unit 11 shown in (2) and Figure 3 In the image 32 of the second camera unit 12 shown in (3), the position of the front vehicle 200 being photographed is shifted left and right. Furthermore, a first parallax w1[pix] is generated between the position of the left rear tire (hereinafter also referred to as the first object) 21 photographed by the image 31 of the first camera unit 11 and the position of the first object 21 photographed by the image 32 of the second camera unit 12.

[0043] The second disparity calculation unit 14 performs a second disparity w2 [pixel] calculation based on the position of the first object 21 in the image captured by the first camera unit 11 and the position of the right rear tire (hereinafter also referred to as the second object) 22 in the image captured by the second camera unit 12. For example, the second disparity calculation unit 14 uses the image captured by the first camera unit 11 as a reference image and the image captured by the second camera unit 12 as a reference image to calculate the second disparity w2 [pixel] by template matching.

[0044] Figure 4 This is a diagram illustrating the second parallax. For example... Figure 4 As shown in (1), when the camera device 10 takes pictures of the vehicle 200 in front through the first camera unit 11 and the second camera unit 12, Figure 4 Image 41 of the first camera unit 11 shown in (2) and Figure 4 In the image 42 of the second camera unit 12 shown in (3), the position of the front vehicle 200 being photographed is shifted left and right. Furthermore, the position of the left rear tire 21, which is the first object, captured in the image 41 of the first camera unit 11, and the position of the right rear tire 22, which is the second object, captured in the image 42 of the second camera unit 12, are set as a second parallax w2[pix].

[0045] The hypothetical baseline length calculation unit 15 uses the first parallax w1 [pixel], the second parallax w2 [pixel], and the baseline length B1 [mm], which is the interval distance between the first camera unit 11 and the second camera unit 12, to calculate the hypothetical baseline length B2 [mm] by adding the interval distance x [mm] from the first object 21 to the second object 22 to the baseline length B1 [mm]. Furthermore, the value of the baseline length B1 [mm] is pre-stored in the control unit 10b.

[0046] The correction unit 16 corrects the parallax shift between the first camera unit 11 and the second camera unit 12 based on the hypothetical baseline length B2 [mm]. In this embodiment, the correction value α for correcting the parallax shift is calculated based on the first hypothetical baseline length B2_t1 [mm], which is the hypothetical baseline length at the first shooting time t1, and the second hypothetical baseline length B2_t2 [mm], which is the hypothetical baseline length at the second shooting time t2.

[0047] Figure 5 It is a diagram illustrating the ranging principle of a stereo camera and the length of the imaginary baseline.

[0048] In this embodiment, the distance z [mm] from the first camera unit 11 and the second camera unit 12 to the left and right rear tires 21 and 22 of the front vehicle 200 in the optical axis direction is the same. Figure 5 As shown, the imaging unit 10a of the imaging device 10 has lenses 111 and 121 of the first imaging unit 11 and the second imaging unit 12, and imaging elements (e.g., CMOS elements) 112 and 122 of the first imaging unit 11 and the second imaging unit 12. The imaging unit 10a sets the focal length of the lenses 111 and 121 to f [mm].

[0049] exist Figure 5 In the example shown, the distance from lenses 111 and 121 to the left and right rear tires 21 and 22 of the front vehicle 200 along the optical axis is set as z [mm], and the interval distance from the left rear tire 21 to the right rear tire 22 of the front vehicle 200 is set as x [mm]. Furthermore, the interval distance between the left and right camera units 11 and 12 is set as the baseline length B1 [mm], and the length of the baseline length B1 [mm] plus the interval distance x [mm] between the left and right rear tires 21 and 22 is set as the imaginary baseline length B2 [mm].

[0050] In the absence of parallax shift

[0051] The first disparity w1[pix] and the second disparity w2[pix] are obtained by the following equations (1) and (2).

[0052] w1=(f×B1) / (z) ・ ・ ・ (1)

[0053] w2=(f×B2) / (z) ・ ・ ・ (2).

[0054] According to equation (1)

[0055] z=(f×B1) / (w1) ・ ・ ・ (3).

[0056] According to equation (2)

[0057] B2=(w2×z) / (f) ・ ・ ・ (4).

[0058] If we substitute (Equation 3) into equation (4), then

[0059] B2=(w2)×((f×B1) / (w1)) / (f)

[0060] =B1×(w1 / w2) ・ ・ ・ (5).

[0061] The baseline length B1 [mm] and the hypothetical baseline length B2 [mm] are fixed values ​​and will not change even if the distance z [mm] between the vehicle 100 and the vehicle in front 200 changes according to the shooting time. Therefore, in the absence of parallax shift, the hypothetical baseline length B2 [mm] will not change even if the distance z [mm] is changed. For example, the result (6) of calculating the hypothetical baseline length B2 (10m) when z=10m [m] and the result (7) of calculating the hypothetical baseline length B2 (20m) when z=20m [m] have the relationship (6)B2(10m)=(7)B2(20m).

[0062] On the other hand, in the case of parallax shift Δw,

[0063] The first parallax w1[pix] and the second parallax w2[pix] are represented by the following equations (1') and (2'),

[0064] w1+Δw=(f×B1) / (z) ・ ・ ・ (1')

[0065] w2+Δw=(f×B2) / (z) ・ ・ ・ (2').

[0066] According to equation (1')

[0067] z=(f×B1) / (w1+Δw) ・ ・ ・ (3').

[0068] According to equation (2')

[0069] B2=((w2+Δw)×z) / (f) ・ ・ ・ (4').

[0070] If we substitute equation (3') into equation (4'), then

[0071] B2=(w2+Δw)×((f×B1) / (w1+Δw)) / (f)

[0072] =B1×((w1+Δw) / (w2+Δw)) ・ ・ ・ (5').

[0073] In cases where parallax shift occurs, for example, the result (6') of calculating the hypothetical baseline length B2 (10m) when z=10m[m] is different from the result (7') of calculating the hypothetical baseline length B2 (20m) when z=20m[m], and the relationship becomes (6')≠(7').

[0074] In this embodiment, when (6') ≠ (7'), the following formula (8) is used to set the correction value α for the relationship (6') = (7') to hold.

[0075] B2=B1×(w2+Δw+α) / (w1+Δw+α) ・ ・ ・ (8)

[0076] Figure 2 This is a flowchart illustrating the parallax offset correction method of the camera device according to the first embodiment. Figure 7 It is a diagram showing the positional relationship between the vehicle and the vehicle in front at the first and second shooting times. Figure 7 The symbol 700 indicates that vehicle 100 is traveling in the lane between the white line 71 and the roadside strip 72, while vehicle 200 is traveling with a gap z1 in front of it. Furthermore, the symbol 701 indicates that vehicle 200 is traveling with a gap z2 in front of vehicle 100.

[0077] Figure 2 The processing of S101 to S103 is in Figure 7 The processing of the image captured at the first shooting time t1 under the condition indicated by symbol 700, the processing in S105 to S108 is... Figure 7 The processing of the image captured at the second shooting time t2 under the condition shown by symbol 701. At the first shooting time t1, the distance between the vehicle 100 and the vehicle in front 200 is z1, while at the second shooting time t2, the distance between the vehicle 100 and the vehicle in front 200 increases to z2.

[0078] The first parallax calculation unit 13 calculates the first parallax w1_t1[pix] at the first shooting time t1 (S101), and the second parallax calculation unit 14 calculates the second parallax w2_t1[pix] at the first shooting time t1 (S102).

[0079] The hypothetical baseline length calculation unit 15 uses the first parallax w1_t1[pix] at the first shooting time t1, the second parallax w2_t1[pix] at the first shooting time t1, and the baseline length B1[mm] to calculate the first hypothetical baseline length B2_t1[mm] (S103).

[0080] Then, it is determined whether a predetermined time has elapsed since the first shooting time t1 (S104). If it is determined that the predetermined time has elapsed ("Yes" in S104), the process moves to processing the image captured at the second shooting time t2. In this embodiment, since a predetermined time has elapsed since the first shooting time t1, it is assumed that the distance between the vehicle 100 and the preceding vehicle 200 has changed, and this moment is taken as the second shooting time t2 for shooting. Alternatively, the distance z to the preceding vehicle 200 can be measured, and the moment when the change in distance is detected since the first shooting time t1 can be taken as the second shooting time t2.

[0081] The first parallax calculation unit 13 calculates the first parallax w1_t2[pix] at the second shooting time t2 (S105), and the second parallax calculation unit 14 calculates the second parallax w2_t2[pix] at the second shooting time t2 (S106).

[0082] The hypothetical baseline length calculation unit 15 uses the first parallax w1_t2[pix] at the second shooting time t2, the second parallax w2_t2[pix] at the second shooting time t2, and the baseline length B1[mm] to calculate the second hypothetical baseline length B2_t2[mm] (S107).

[0083] The correction unit 16 calculates a correction value α that makes the first imaginary baseline length B2_t1 [mm] and the second imaginary baseline length B2_t2 [mm] equal (S108).

[0084] In the camera device 10 of this embodiment, the first parallax calculation unit 13 calculates the first parallax w1_t1[pix] at the first shooting time t1 and the first parallax w1_t2[pix] at the second shooting time t2, and the second parallax calculation unit 14 calculates the second parallax w2_t1[pix] at the first shooting time t1 and the second parallax w2_t2[pix] at the second shooting time t2.

[0085] Then, the hypothetical baseline length calculation unit 15 calculates the first hypothetical baseline length B2_t1[mm] using the first parallax w1_t1[pix] at the first shooting time t1, the second parallax w2_t1[pix] at the first shooting time t1, and the baseline length B1[mm], and calculates the second hypothetical baseline length B2_t2[mm] using the first parallax w1_t2[pix] at the second shooting time t2, the second parallax w2_t2[pix] at the second shooting time t2, and the baseline length B1[mm]. The correction unit 16 sets the value that makes the first hypothetical baseline length B2_t1[mm] and the second hypothetical baseline length B2_t2[mm] equal as the correction value α.

[0086] Next, the effects of the camera device 10 in this embodiment will be explained.

[0087] For example, such as Figure 5 As shown, the baseline length B1, which is the distance between the first camera unit 11 and the second camera unit 12, is a fixed value, and the distance x between the left and right rear tires 21 and 22 is also a fixed value. Therefore, in the absence of parallax shift in the camera device 10, the hypothetical baseline length B2 calculated by equation (5) using the first parallax w1, the second parallax w2, and the baseline length B1 also remains unchanged regardless of the distance z from the vehicle in front 200.

[0088] On the other hand, in the case of parallax shift in the camera device 10, the hypothetical baseline length B2 calculated by formula (5') using the first parallax w1, the second parallax w2, the parallax error Δw, and the baseline length B1 varies according to the distance z from the vehicle in front 200.

[0089] Therefore, by calculating the imaginary baseline length B2 at different intervals, and when the first imaginary baseline length B2_t1, which is the imaginary baseline length B2 at the first shooting time t1, is inconsistent with the imaginary baseline length B2_t2 at the second shooting time t2, a correction value α is set using the above formula (8) to establish the relationship (6') = (7'), and this correction value α can be used to correct the parallax shift. According to the camera device 10 of this embodiment, for example, it is possible to correct the parallax shift by taking pictures of the vehicle 200 ahead while the vehicle 100 is moving.

[0090] [Second Implementation]

[0091] Figures 8-10 This is a flowchart illustrating the parallax offset correction method of the camera device according to the second embodiment. Figure 11 This diagram illustrates how the number of pixels corresponding to the baseline length in S205 is calculated. Figure 12 This diagram illustrates a method for calculating the distance between the left and right rear tires of a vehicle in front using the camera device of the second embodiment. Furthermore, components identical to those in the first embodiment are given the same reference numerals, and their detailed descriptions are omitted.

[0092] The feature of this embodiment is that it is configured such that, unlike the first embodiment, the parallax does not need to be measured multiple times at time intervals, but only needs to be measured once to calculate the correction value.

[0093] Similar to the first embodiment, the first camera unit 11 and the second camera unit 12 take pictures of the first object 21 and the second object 22 at positions that are equidistant from the first object 21 and the second object 22 of the preceding vehicle 200.

[0094] The first parallax calculation unit 13 calculates the first parallax w1[pix] based on the position of the first object 21 in the image captured by the first camera unit 11 and the position of the first object 21 in the image captured by the second camera unit 12 (S201). In this embodiment, the position of one tire of the front vehicle 200 is taken as the position of the first object 21, and the first parallax w1[pix] is calculated.

[0095] Then, the second parallax calculation unit 14 calculates the second parallax w2[pix] based on the position of the first object 21 in the image captured by the first camera unit 11 and the position of the second object 22 in the image captured by the second camera unit 12 (S202). In this embodiment, the position of one tire of the front vehicle 200 is taken as the position of the first object 21, and the position of the other tire is taken as the position of the second object 22, and the second parallax w2[pix] is calculated.

[0096] The hypothetical baseline length calculation unit 15 uses the first parallax w1 [pixel], the second parallax w2 [pixel], and the baseline length B1 [mm] to calculate the third hypothetical baseline length B23 [mm] (S203). The third hypothetical baseline length B23 [mm] is the length of the interval distance x [mm] from the first object 21 to the second object 22 plus the baseline length B1 [mm]. The processing of S201 to S203 is the same as that of S101 to S103 in the first embodiment.

[0097] Next, the hypothetical baseline length calculation unit 15 calculates the number of pixels w3 [pixels] on the image captured by the first camera unit 11 or the second camera unit 12 that corresponds to the baseline length B1 (S205). The hypothetical baseline length calculation unit 15 calculates the number of pixels w3 corresponding to the baseline length B1 based on the distance that an object photographed at the center position of the image captured by either the first camera unit 11 or the second camera unit 12 is separated from the center position of the image captured by the other of the first camera unit 11 and the second camera unit 12.

[0098] For example, such as Figure 12 As shown, the first camera unit 11 and the second camera unit 12 photograph the vehicle 200 in front, thereby photographing both the third object 23 and the fourth object 24 of the vehicle 200. Figure 11 As shown, the third object 23 is the object photographed at the center position of the image of the second camera unit 12, and the fourth object 24 is the object photographed at the center position of the image of the first camera unit 11.

[0099] The third object 23 is captured in the image of the first camera unit 11 at a predetermined distance to the left of the fourth object 24, which is located at its center position. This predetermined distance is the parallax of the third object 23, which is the number of pixels w3[pixel] on the image captured by the first camera unit 11 or the second camera unit 12 that corresponds to the baseline length B1. That is, by calculating the parallax of the third object 23, the number of pixels w3[pixel] corresponding to the baseline length B1 can be calculated. The parallax of the third object 23 is obtained by detecting the third object 23 captured in the image of the first camera unit 11 based on the third object 23 captured in the image of the second camera unit 12, and by the number of pixels representing the width of the distance between the center position of the image of the first camera unit 11 and the third object 23.

[0100] Next, the hypothetical baseline length calculation unit 15 calculates the number of pixels between the first object 21 and the second object 22, i.e., the number of pixels w4[pix] between the left and right rear tires 21 and 22 of the front vehicle 200, on the image captured by the first camera unit 11 or the second camera unit 12 (S206).

[0101] Furthermore, by using the number of pixels w3[pix] equivalent to the baseline length B1, the number of pixels w4 between the first object 21 and the second object 22, and the ratio of the baseline length B1, the distance between the first object 21 and the second object 22 can be calculated, that is, the distance x[mm] between the left and right rear tires 21 and 22 of the front vehicle 200 can be calculated by the ratio calculation of the following formula (9) (S207).

[0102] Number of pixels w3 [pix] ∶ Number of pixels w4 [pix] = Baseline length B1 [mm] ∶ Distance x [mm] … (9)

[0103] Then, the fourth imaginary baseline length B24 is calculated as the length of the interval distance x [mm] from the first object 21 to the second object 22 plus the baseline length B1 [mm] (S208).

[0104] The correction unit 16 calculates a correction value α (S209) that makes the third imaginary baseline length B23 [mm] and the fourth imaginary baseline length B24 equal. The correction unit 16 uses the correction value α to correct the parallax offset between the first camera unit 11 and the second camera unit 12.

[0105] According to the camera device 10 of this embodiment, it is not necessary to leave time difference to measure parallax multiple times as in the first embodiment. Instead, the correction value can be calculated by measuring parallax only once, and parallax offset can be corrected during the movement of the vehicle 100.

[0106] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the described embodiments, and various design changes can be made without departing from the spirit of the invention as set forth in the claims. For example, the embodiments described in detail are for the purpose of easily understanding and illustrating the present invention, and are not necessarily limited to embodiments having all the described configurations. Furthermore, a part of the configuration of some embodiments can be replaced with the configuration of other embodiments, and the configuration of other embodiments can be added to the configuration of some embodiments. Moreover, for a part of the configuration of each embodiment, other configurations can be added, deleted, or replaced.

[0107] Symbol Explanation

[0108] 10…Camera device, 11…First camera unit, 12…Second camera unit, 13…First parallax calculation unit, 14…Second parallax calculation unit, 15…Imaginary baseline length calculation unit, 16…Correction unit, 100…Vehicle, 200…Forward vehicle (object), B1…Baseline length, B2…Imaginary baseline length, x…Interval distance between the left and right rear tires 21 and 22, α…Correction value, w1…First parallax, w2…Second parallax, z…Distance.

Claims

1. A camera device that captures images of a first object and a second object at positions equidistant from each other, and corrects for parallax shift, characterized in that it comprises: First Camera Department; The second camera unit is arranged in pair with the first camera unit at a certain distance away in a direction intersecting the direction toward the object; The first parallax calculation unit calculates the first parallax of the first object based on the position of the first object in the image captured by the first camera unit and the position of the first object in the image captured by the second camera unit. The second parallax calculation unit calculates a second parallax as the parallax between the first object and the second object based on the position of the first object in the image captured by the first camera unit and the position of the second object in the image captured by the second camera unit. The hypothetical baseline length calculation unit uses the first parallax, the second parallax, and the baseline length, which is the distance between the first camera unit and the second camera unit, to calculate the hypothetical baseline length, which is the length obtained by adding the distance between the first object and the second object to the baseline length. as well as The correction unit corrects the parallax offset between the first camera unit and the second camera unit based on the hypothetical baseline length.

2. The camera device as described in claim 1, characterized in that, The correction unit calculates the correction value for the parallax shift based on the imaginary baseline length at the first shooting time (i.e., the first imaginary baseline length) and the imaginary baseline length at the second shooting time (i.e., the second imaginary baseline length).

3. The camera device as described in claim 2, characterized in that, The first parallax calculation unit calculates the first parallax at the first shooting time and the first parallax at the second shooting time. The second parallax calculation unit calculates the second parallax at the first shooting time and the second parallax at the second shooting time. The imaginary baseline length calculation unit uses the first parallax at the first shooting time, the second parallax at the first shooting time, and the baseline length to calculate the first imaginary baseline length, and uses the first parallax at the second shooting time, the second parallax at the second shooting time, and the baseline length to calculate the second imaginary baseline length. The correction unit sets the value that makes the length of the first imaginary baseline equal to the length of the second imaginary baseline as the correction value.

4. The camera device as described in claim 1, characterized in that, The first disparity calculation unit uses the image captured by the first camera unit as a reference image and the image captured by the second camera unit as a reference image to calculate the first disparity through template matching. The second disparity calculation unit uses the image captured by the first camera unit as the reference image and the image captured by the second camera unit as the reference image to calculate the second disparity through template matching.

5. The camera device as described in claim 1, characterized in that, The hypothetical baseline length calculation unit uses the first disparity, the second disparity, and the baseline length to calculate a third hypothetical baseline length, which is the length obtained by adding the baseline length to the distance between the first object and the second object. The hypothetical baseline length calculation unit calculates the number of pixels on the image captured by the first camera unit or the second camera unit that corresponds to the baseline length and the number of pixels between the first object and the second object. The hypothetical baseline length calculation unit calculates the interval distance from the first object to the second object by using the number of pixels equivalent to the baseline length, the number of pixels between the first object and the second object, and the ratio of the baseline length. The hypothetical baseline length calculation unit calculates a fourth hypothetical baseline length, which is the length obtained by adding the baseline length to the distance between the first object and the second object. The correction unit calculates the correction value for the disparity shift based on the third and fourth hypothetical baseline lengths.

6. The camera device as described in claim 5, characterized in that, The hypothetical baseline length calculation unit calculates the number of pixels equivalent to the baseline length based on the distance that an object photographed at the center position of an image captured by one of the first and second cameras is separated from the center position of an image captured by the other of the first and second cameras.

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