Method for detecting optical axis deviation angle and position relation of binocular camera

Abstract

Initial positions of the binocular camera, the positioner, the laser module and the cross graph card are limited through the track support, moving modes of the binocular camera, the positioner, the laser module and the cross graph card are limited, the A eye of the camera, the middle point of the positioner and the middle point of the laser module are opposite, and then the laser module is used for lighting the cross graph card. A light spot on a cross graph card is adjusted to be a perfect circle, the midpoint of the light spot coincides with the midpoint of the cross graph card to further level the graph card and align the midpoint, finally, the cross graph card is shot through a camera A, then the optical axis offset of the camera A is calculated according to the shot picture and the distance between the camera A and the cross graph card, and the image is obtained. And the target optical axis offset of the camera B is also calculated, and the position relation of the two optical axis offsets is judged according to whether the two optical axis offsets are consistent or not. According to the invention, the position relation between the two optical axes of the binocular camera can be determined, and the offset can be quantified.

Description

Technical Field

[0001] This invention belongs to the field of machine vision technology, specifically relating to a method for detecting the optical axis offset angle and positional relationship of a binocular camera. Background Technology

[0002] In existing technologies, the detection of the optical axis of a binocular camera mainly involves determining whether its optical axis is parallel. However, in practical applications, it is not enough to simply check whether its optical axis is parallel. It is also necessary to further know the optical axis offset angle, especially when its optical axis is not parallel, in order to guide the design of the baseline length correction scheme for the binocular camera. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for detecting the optical axis offset angle and positional relationship of a binocular camera. The method of the present invention can not only identify the positional relationship of the two optical axes of the binocular camera, i.e. whether they are parallel, but also identify the specific offset angle of each optical axis.

[0004] The present invention solves the above-mentioned technical problems as follows: A method for detecting the optical axis offset angle and positional relationship of a binocular camera, characterized by comprising the following steps:

[0005] S1. Install the binocular camera, locator, laser module, and crosshair card onto the track bracket in front to back order, so as to control their positional relationship through the track bracket. The locator and laser module are fixed together and centered opposite each other, and can move linearly forward, backward, up, down, and left and right as a whole. At the same time, the pitch angle and tilt angle of the binocular camera, locator, and laser module are adjustable, and the crosshair card can move linearly up, down, left, and right.

[0006] S2. Move the locator and laser module closer to the binocular camera and make the cone at one end of the locator point directly at the midpoint of one of the binocular cameras, namely the A eye, so that the midpoints of the A eye, the locator, and the laser module are relative to each other.

[0007] S3. Turn on the laser module, which emits a solid circular spot. Move the crosshair card so that the midpoint of the solid circular spot coincides with the midpoint of the crosshair card.

[0008] S4. Determine whether the solid circular spot presented on the crosshair is a perfect circle. If so, it indicates that the planes containing the binocular camera, laser module, and crosshair are parallel (parallelism of the planes containing the camera and laser module means that they are parallel with the outer edges of the lenses of the camera and laser module as a reference). Figure 2If the solid circular spot on the crosshair card is not parallel to the plane of the binocular camera, laser module, and crosshair card, then adjust the pitch and / or tilt angle of the binocular camera, locator, and laser module as a whole to make the solid circular spot on the crosshair card a perfect circle. Then adjust the binocular camera, locator, and laser module as a whole up and down and / or left and right (this requires that the binocular camera, locator, and laser module as a whole can also move vertically up and down and left and right in a straight line), or move the crosshair card up and down and / or left and right to make the midpoint of the solid circular spot coincide with the midpoint of the crosshair card again.

[0009] S5. Remove the locator and laser module as a whole, and then take a picture of the crosshair card through the A-eye of the binocular camera. Calculate the optical axis offset of the A-eye based on the captured image and the distance between the A-eye and the crosshair card.

[0010] S6. Reinstall the locator and laser module, and then move the locator and laser module so that the cone of the locator points directly at the midpoint of the other eye of the binocular camera, namely eye B, so that the midpoints of eye B, the locator and the laser module are aligned.

[0011] S7. Remove the locator and laser module, take a picture of the crosshair card through the B-eye of the binocular camera, calculate the optical axis offset of the B-eye based on the captured image and the distance between the B-eye and the crosshair card, and determine their positional relationship based on whether the two optical axis offsets (including the offset direction) are consistent.

[0012] If the offsets of the two optical axes are the same, it indicates that they are parallel; otherwise, they are not parallel. When the result indicates that they are not parallel, the baseline length of the binocular camera can be corrected by software based on the detected optical axis offset data. Therefore, the method of this invention achieves more comprehensive detection of the binocular camera.

[0013] The binocular camera, locator, and laser module can also move linearly back and forth to adjust the distance to the map card if it is not suitable.

[0014] Beneficial effects:

[0015] This invention defines the initial positions of the binocular camera, locator, laser module, and crosshair chart using a track support, and also defines their movement method. First, the midpoints of camera A, the locator, and the laser module are aligned. Then, the laser module illuminates the crosshair chart. By adjusting the light spot on the crosshair chart to a perfect circle and aligning its midpoint with the midpoint of the crosshair chart, the chart is further leveled and aligned with the midpoint. Finally, camera A captures an image of the crosshair chart. Based on the captured image and the distance between camera A and the crosshair chart, the optical axis offset of camera A is calculated, and the optical axis offset of camera B is also calculated. The positional relationship is determined by whether the two optical axis offsets are consistent. Therefore, this invention not only clearly defines the positional relationship between the two optical axes of the binocular camera but also quantifies their offsets. This allows for software correction of the binocular camera's baseline length when the two optical axes are not parallel, ensuring the accuracy of depth recognition. This invention is applicable to the detection of optical axis positional relationships and offsets of binocular cameras with different shapes and focal lengths, exhibiting good versatility. Attached Figure Description

[0016] Figure 1 This is a flowchart of the method for detecting the optical axis offset angle and positional relationship of a binocular camera according to the present invention;

[0017] Figure 2 This is a schematic diagram of the track support structure of the present invention;

[0018] Figure 3 This is a schematic diagram of the positioner's structure;

[0019] Figure 4 This is a schematic diagram for calculating the optical axis offset. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] A flowchart of a method for detecting the optical axis offset angle and positional relationship of a binocular camera in this embodiment is shown below. Figure 1 As shown, it includes the following steps:

[0022] S1. Install the binocular camera, locator, laser module, and crosshair card onto the track bracket in a front-to-back order, so as to control their positional relationship through the track bracket.

[0023] The structure of the track support used in this embodiment is as follows: Figure 2As shown, the system includes several linear guide rails, including rails A, B, C, and D, and several linearly retractable brackets, including brackets A, B, and C. The locator and laser module are fixed together on the rail brackets, with their centers facing each other, and are mounted as a whole on a vertically positioned bracket B. Bracket B is set on a guide rail B positioned in the left-right direction, and guide rail B is mounted on a guide rail A positioned in the front-back direction. Therefore, the locator and laser module can move up and down along bracket B, left and right along guide rail B, and front and back along guide rail A. A binocular camera is fixed on guide rail A and located in front of the locator and laser module. A crosshair is mounted on a rearward guide rail D positioned in the left-right direction via bracket C, allowing it to move up and down and left and right. Guide rail A is mounted on guide rail C positioned in the front-back direction via bracket A, allowing the binocular camera, locator, and laser module to move back and forth along guide rail C to move closer to or further away from the crosshair, and also to move up and down via bracket A. Figure 2 As shown, a three-axis gimbal is provided at the upper end of bracket A, which allows the pitch and tilt angles of the binocular camera, locator, and laser module as a whole to be adjustable. In other embodiments, guide rails can be further added to allow the binocular camera, locator, and laser module as a whole to move linearly left and right.

[0024] S2. Move the locator and laser module closer to the binocular camera and make the cone at one end of the locator point directly at the midpoint of one of the binocular cameras, namely the A eye, so that the midpoints of the A eye, the locator, and the laser module are aligned.

[0025] Figure 3 This is a schematic diagram of the locator, which is a device with symmetrical cones at both ends to facilitate adjustment of the midpoint between the camera and the laser film assembly.

[0026] The laser module in this embodiment is essentially a laser, which is typically used for industrial laser positioning, aiming devices, etc.

[0027] S3. Turn on the laser module, which emits a solid circular spot. Move the crosshair card so that the midpoint of the solid circular spot coincides with the midpoint of the crosshair card.

[0028] S4. Determine whether the solid circular spot presented on the crosshair is a perfect circle. If so, it indicates that the planes containing the binocular camera, laser module, and crosshair are parallel (parallelism of the planes containing the camera and laser module means that they are parallel with reference to the outer circular edges of the lenses of the camera and laser module, such as...). Figure 2(As shown) and the midpoints are opposite each other; otherwise, it indicates that the planes on which the binocular camera, laser module, and crosshair are located are not parallel. In this case, adjust the pitch and / or tilt angles of the binocular camera, locator, and laser module as a whole so that the solid circle on the crosshair is a perfect circle. Then move the crosshair up and down and / or left and right so that the midpoint of the solid circle coincides with the midpoint of the crosshair again. Alternatively, the midpoint of the solid circle can be made to coincide with the midpoint of the crosshair by adjusting the binocular camera, locator, and laser module as a whole. However, in this case, the binocular camera, locator, and laser module as a whole should be able to move linearly up and down and left and right.

[0029] During the above process, if the distance between the binocular camera, locator, and laser module and the pattern card is not appropriate, they can be moved back and forth along guide rail C to adjust the distance to the cross pattern card.

[0030] S5. Remove the locator and laser module as a whole, and then take a picture of the crosshair card through the A-eye of the binocular camera. Calculate the optical axis offset of the A-eye based on the captured image and the distance between the A-eye and the crosshair card.

[0031] S6. Reinstall the locator and laser module, and then move the locator and laser module so that the cone of the locator points directly at the midpoint of the other eye of the binocular camera, namely eye B, so that the midpoints of eye B, the locator and the laser module are aligned.

[0032] S7. Remove the locator and laser module, take a picture of the crosshair card through the B-eye of the binocular camera, calculate the optical axis offset of the B-eye based on the captured image and the distance between the B-eye and the crosshair card, and determine their positional relationship based on whether the two optical axis offsets (including the offset direction) are consistent.

[0033] This embodiment defines the initial positions of the binocular camera, locator, laser module, and crosshair chart using a track support, and also defines their movement method. First, the midpoints of camera A, the locator, and the laser module are aligned. Then, the laser module illuminates the crosshair chart. By adjusting the light spot on the crosshair chart to a perfect circle with its midpoint coinciding with the midpoint of the crosshair chart, the chart is further leveled and aligned with the midpoint. Finally, camera A captures an image of the crosshair chart. Based on the captured image and the distance between camera A and the crosshair chart, the optical axis offset of camera A is calculated. Similarly, the optical axis offset of camera B is calculated. The positional relationship is determined based on whether the two optical axis offsets are consistent. Therefore, this invention not only clearly defines the positional relationship between the two optical axes of the binocular camera but also quantifies their offsets, enabling more comprehensive detection of the binocular camera. This allows for software correction of the baseline length of the binocular camera when the two optical axes are not parallel, thereby ensuring the accuracy of depth recognition by the binocular camera.

[0034] Figure 4 This is a schematic diagram for calculating the optical axis offset. Based on the image captured by the camera, the distance t' (t' in pixels) to P'O' is found. By using the relationship between the pixel difference and the difference between the image and the card, the distance t to PO is found. Given the distance d from the camera to the image, the offset angle α can be obtained using trigonometric functions.

[0035] This invention is applicable to the detection of the optical axis position relationship and offset of binocular cameras of different shapes and focal lengths. It has good versatility, is simple to operate, and has significant application value.

Claims

1. A method for detecting the angle and position relationship of optical axis offset of a binocular camera, characterized in that, The method comprises the following steps: S1, mounting the binocular camera, the positioner, the laser module and the cross card on the track support in the order from front to back to control their positional relationship through the track support, wherein the positioner and the laser module are fixed together and have a central relative position, and the whole can move linearly forward and backward, up and down and left and right, and the pitch angle and the tilt angle of the whole of the binocular camera, the positioner and the laser module are adjustable, and the cross card can move linearly up and down and left and right; S2, moving the positioner and the laser module close to the binocular camera and making the cone head at one end of the positioner point directly at the midpoint of one of the two eyes of the binocular camera, i.e. the midpoint of the A eye, so that the midpoints of the A eye, the positioner and the laser module are opposite to each other; S3, turning on the laser module, which emits a solid round spot, and moving the cross card so that the midpoint of the solid round spot coincides with the midpoint of the cross card; S4, judging whether the solid round spot presented on the cross card is a perfect circle, otherwise adjusting the pitch angle and / or the tilt angle of the whole of the binocular camera, the positioner and the laser module so that the solid round spot presented on the cross card is a perfect circle, and then adjusting the whole of the binocular camera, the positioner and the laser module up and / or down and / or left and / or right or moving the cross card up and / or down and / or left and / or right so that the midpoint of the solid round spot and the midpoint of the cross card coincide with each other again; S5, removing the positioner and the laser module as a whole, then shooting the cross card through the A eye of the binocular camera, and calculating the optical axis offset of the A eye according to the shooting picture and the distance between the A eye and the cross card; S6, reinstalling the positioner and the laser module, then moving the positioner and the laser module so that the cone head of the positioner points directly at the midpoint of the other eye of the binocular camera, i.e. the midpoint of the B eye, so that the midpoints of the B eye, the positioner and the laser module are opposite to each other; S7, removing the positioner and the laser module, shooting the cross card through the B eye of the binocular camera, calculating the optical axis offset of the B eye according to the shooting picture and the distance between the B eye and the cross card, and determining the positional relationship of the two optical axes according to whether the optical axis offsets of the two eyes are consistent.

2. The method for detecting the optical axis offset angle and the positional relationship of a binocular camera according to claim 1, characterized in that, The whole of the binocular camera, the positioner and the laser module can also move linearly forward and backward.

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