CN102878925A - Synchronous calibration method for binocular video cameras and single projection light source - Google Patents

Abstract

The invention belongs to the field of three-dimensional machine vision and relates to a synchronous calibration method for two high-precision cameras and a single projection light source. The present invention regards two cameras and a single projection light source as two monocular three-dimensional measurement systems. While calibrating the coordinate positions of the cameras and projection light sources, the coordinate transformation relationship between the two camera coordinate systems can be obtained, and then the two The three-dimensional coordinate data collected by three cameras are unified into one coordinate system. On the basis of not increasing the hardware cost, the present invention can change the disadvantage that the existing binocular vision measurement system can only measure the intersection of two cameras to collect three-dimensional scenes, and through the synchronous calibration method of two cameras and projection light source introduced by the present invention, The union of the three-dimensional scenes collected by the two cameras can be obtained, the measurement range is increased, the measurement times are reduced, and the measurement time is saved.

Description

Synchronous Calibration Method for Binocular Camera and Single Projection Light Source

technical field

The present invention relates to a high-precision synchronous calibration method for a binocular camera and a single projection light source. More specifically, the calibration method provided by the present invention can simultaneously obtain the internal and external parameters of two cameras and a single projection light source, and automatically integrate the two The three-dimensional information captured by the camera is spliced.

Background technique

The 3D reconstruction method has been widely used in many fields such as industrial inspection, reverse engineering, human body scanning, cultural relics protection, clothing, shoes and hats, etc. It has the advantages of fast speed and high precision for free-form surface detection. According to the number of cameras used, three-dimensional reconstruction methods are divided into: monocular, binocular and multi-eye three-dimensional reconstruction systems.

Monocular systems generally include a single camera and a single projection light source, mainly using Phase Measuring Profilometry (PMP), also known as Phase Shifting Profilometry (PSP) for three-dimensional measurement. The phase measurement method is to project a fixed-period luminance image that changes according to the law of a trigonometric function (sine or cosine) onto the measured object. The luminance image undergoes a uniform phase shift greater than 3 steps, preferably 4-6 steps of uniform phase shift. Shift, project 4-6 times of brightness image to the object, and finally complete a cycle of phase shift. Each point on the object will obtain several different brightness values in the image after being projected by the phase-shifted image. This luminance value undergoes a dephasing operation to obtain a unique phase value. Through the calibration method of a single camera and a single projection light source, the geometric position information of the camera and projection light source can be obtained, and the three-dimensional coordinate information of the measured scene can be obtained by using the obtained phase value and related geometric position information.

The binocular system generally includes two cameras and a projection light source, and mainly uses stereo matching method for three-dimensional reconstruction. That is, a certain point P in the object space coordinate system will capture the imaging points P1 and P2 of point P in two cameras respectively, using the triangular relationship formed by the point P in the object space and the two imaging points P1 and P2, and The positional relationship and internal parameter information between the two cameras that have been calibrated in advance can be used to calculate the three-dimensional coordinates of point P.

A multi-camera system is generally based on multiple monocular or binocular systems, and its principle is the splicing and integration of monocular or binocular systems.

Since the existing binocular system obtains three-dimensional coordinate information by utilizing the triangular relationship between the object space point P and the two imaging points P1 and P2, the advantage is that no calibration of the projection light source is required. The disadvantage is that only the part that can be photographed by two cameras can obtain the three-dimensional coordinate information. If only one camera can photograph the range, the three-dimensional point cloud cannot be obtained because the three-dimensional measurement relationship cannot be formed. That is to say, the existing The binocular system can only obtain the intersection of the scenes captured by the two cameras.

The present invention provides a synchronous calibration method for a binocular camera and a single projection light source without increasing hardware costs, but the biggest difference between this method and the existing binocular system is that as long as there is an object space point that can be photographed by a camera, Both can obtain three-dimensional coordinate information, so the calibration method provided by the present invention can obtain the union of the scenes captured by the two cameras, increase the measurement range, reduce the number of measurements, and save measurement time.

Contents of the invention

The invention provides a synchronous calibration method for a single camera and a single projection light source. The parameters after calibration can be applied to high-precision three-dimensional measurement, which can make up for the defects of existing calibration methods and improve the accuracy of calibration and three-dimensional measurement.

The hardware system of the single camera and single projection light source synchronous calibration system includes:

A projection light source device for projecting optical signals, the resolution of the projection light source is L _R × L _C , and the number of projection light sources is 1;

Computers for precision control, image acquisition and data processing;

A color or black-and-white camera used to collect images, the image resolution is C _R × C _C , and the number of cameras is 1;

A scanning platform for placing the projection light source device and the color or black and white camera;

The method for synchronous calibration of two cameras and a single projection light source designed by the present invention, the specific operation steps are as follows:

Step 1: Fix two color or black-and-white cameras and a projection light source (the resolution of the projection light source is L _R × L _C ) on the scanning platform, and determine that the color Or the positions of the black-and-white camera and the projection light source will not be changed, wherein the color or black-and-white camera placed on the left side of the projection light source is called the left camera, and the color or black-and-white camera placed on the right side of the projection light source is called the right camera. Camera, although there is only one projection light source, it can form a monocular three-dimensional measurement system with the left camera and the right camera. When the projection light source and the left camera form a three-dimensional measurement system, the projection light source is called the left projection light source , when the projection light source and the right camera form a three-dimensional measurement system, the projection light source is called the right projection light source, and the object space coordinate system is called the left object space coordinate system in the three-dimensional measurement system formed with the left camera, and the right camera constitutes The three-dimensional measurement system is called the right object space coordinate system; place the pre-processed calibration target at a position close to the measured object, that is, within the range of ±500mm from the measured object, and place the calibration target target, and make sure that the calibration target can be completely photographed by the two color or black-and-white cameras, and that the light signal range that can be projected by the projection light source can cover the location of the calibration target; adjust the The focal length of the two color or black-and-white cameras and the projection light source, so that it is in the best condition;

Step 2: Adjust the position of the calibration target more than 3 times, preferably 5-8 times, and ensure that each position of the calibration target can be adjusted by the two color or black and white The camera is fully photographed, and the light signal range that the projection light source can project can cover the position of the calibration target; each time the target is adjusted, the two color or black and white cameras must be used to perform target image capture. Collect and use the projection light source to project a series of gray code plus 6-step phase shift images to the calibration target, and collect each image projected by the projection light source through the two color or black and white cameras ;

Step 3: Using Zhang Zhengyou’s tablet calibration method, obtain the left camera coordinate system X _C1 , the right camera coordinate system X _C2 , the left projected light source coordinate system X _P1 , the right projected light source coordinate system X _P2 , the left object space coordinate system X _W1 and the right The coordinate relationship between the object space coordinate system X _W2 is shown in the following formula:

X _C1 =R ₁ X _W1 +T ₁ (1)

X _P1 =R ₂ X _W1 +T ₂ (2)

X _C2 =R ₃ X _W2 +T ₃ (3)

X _P2 =R ₄ X _W2 +T ₄ (4)

Step 4: Use the following formula to convert the right camera coordinate system to the left camera coordinate system to unify the coordinates of the two views:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

So far, the calibration process is over.

The beneficial effects of the present invention are: the binocular vision measurement system designed by the present invention can change the disadvantage that the existing binocular vision measurement system can only measure the intersection of three-dimensional scenes collected by two cameras without increasing the hardware cost. The synchronous calibration method of the two cameras and the projection light source introduced by the present invention can obtain the union of the three-dimensional scenes collected by the two cameras, increase the measurement range, reduce the measurement times and save the measurement time.

Description of drawings

Figure 1: 3D reconstruction system with binocular camera and single projection light source;

Figure 2: Flowchart of the synchronous calibration method for two cameras and a single projection light source;

Detailed ways

The 3D reconstruction system with a binocular camera and a single projection light source is shown in Figure 1. In the process of synchronous calibration, it is first necessary to fix the positions of the two cameras and the projection light source on the scanning platform, and make sure that this position will not be changed during the three-dimensional measurement after the calibration is completed. The fixing method is that the projection light source is placed in the middle, and the two cameras are respectively placed on both sides of the projection light source. Place the pre-processed calibration target at a position close to the measured object, place the calibration target, and make sure that the calibration target can be completely captured by the two cameras, and the light signal range that the projection light source can project can cover the location of the calibration target s position. Adjust the focal length of the two cameras and the projection light source to make them in the best condition. Each camera and projection light source can constitute a complete monocular three-dimensional measurement system, and its calibration method has been introduced in detail in the patent "A New Synchronous Calibration Method for a Single Camera and a Single Projection Light Source" submitted by the inventor. The present invention is mainly to simultaneously calibrate the two monocular three-dimensional measurement systems, not only can obtain the parameter information required by the two monocular three-dimensional measurement systems, but also can obtain the positional relationship between the two monocular three-dimensional measurement systems , and the 3D data of the two monocular 3D measurement systems can be spliced to obtain the union of the information of the two scenes.

According to the method in the submitted invention patent "A New Synchronous Calibration Method for a Single Camera and a Single Projection Light Source", it is assumed that each point (x _c1 , y _c1 , z _c1 ) in the coordinate system of the left camera is aligned with the object space coordinate system Each point in (x _w1 , y _w1 , z _w1 ) has the following relationship:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right]<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the three-dimensional measurement system composed of the projection light source and the left camera, each point (x _p1 , y _p1 , z _p1 ) in its coordinate system and each point in the object space coordinate system (x _w1 , y _w1 , z _w1 ) The points have the following relationship:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right]<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Each point (x _c2 , y _c2 , z _c2 ) in the right camera coordinate system has the following relationship with each point in the object space coordinate system (x _w2 , y _w2 , z _w2 ):

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right]<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the three-dimensional measurement system formed by the projection light source and the right camera, each point (x _p2 , y _p2 , z _p2 ) in its coordinate system and each point in the object space coordinate system (x _w2 , y _w2 , z _w2 ) The points have the following relationship:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right]<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In order to simplify the formula, the two cameras and the projection light source are described in detail. The color or black-and-white camera placed on the left side of the projection light source is called the left camera, and the color or black-and-white camera placed on the right side of the projection light source is called the right camera. Although the projection light source has only One, but it can form a monocular three-dimensional measurement system with the left camera and the right camera. When the projection light source and the left camera form a three-dimensional measurement system, the projection light source is called the left projection light source. When the projection light source and the right camera form a three-dimensional measurement system, the projection light source The light source is called a right projection light source. Let the left camera coordinate system be X _C1 , the right camera coordinate system be X _C2 , the left projection light source coordinate system be X _P1 , the right projection light source coordinate system be X _P2 , and the object space coordinate systems when the left and right cameras are calibrated respectively be X _W1 and X _W2 , then the above coordinate relationship can be expressed as a series of formulas as follows:

X _C1 =R ₁ X _W1 +T ₁ (5)

Where: _R1 is the rotation matrix between the left camera coordinate system X _C1 and the object space coordinate system X _W1 coordinate system;

T ₁ is the translation matrix between the left camera coordinate system X _C1 and the object space coordinate system X _W1 coordinate system;

X _P1 =R ₂ X _W1 +T ₂ (6)

Wherein: _R2 is the rotation matrix between the coordinate X _P1 of the projection light source in the three-dimensional measurement system formed by the left camera and the object space coordinate system X _W2 coordinate system;

_T2 is the translation matrix between the coordinate X _P1 of the projection light source and the coordinate system X _W2 of the object space coordinate system in the three-dimensional measurement system constituted by the left camera;

X _C2 =R ₃ X _W2 +T ₃ (7)

Where: _R3 is the rotation matrix between the right camera coordinate system X _C2 and the object space coordinate system X _W2 coordinate system;

T ₃ is the translation matrix between the right camera coordinate system X _C2 and the object space coordinate system X _W2 coordinate system;

X _P2 =R ₄ X _W2 +T ₄ (8)

Wherein: _R4 is the rotation matrix between the coordinate X _P2 of the projection light source in the three-dimensional measurement system formed with the right camera and the object space coordinate system X _W2 coordinate system;

_T4 is the translation matrix between X _P2 and the object space coordinate system X _W2 coordinate system in the three-dimensional measurement system formed by the projection light source and the right camera;

Through the formula X _C1 =R ₁ X _W1 +T ₁ , the following formula can be obtained:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; W</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

Therefore, X _P1 = R ₂ X _W1 + T ₂ can be rewritten as the following formula:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

Through the formula X _C2 = R ₃ X _W2 + T ₃ , the following formula can be obtained:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; W</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

Therefore, the formula X _P2 =R ₄ X _W2 +T ₄ can be rewritten as the following formula:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

Since X _P1 =X _P2 , the following relationship can be obtained:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

therefore:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>$ $<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>$

If the 3D coordinates obtained from the right view captured by the right camera are stitched together with the left view, the rotation and translation matrix between the left coordinate system and the right coordinate system needs to be obtained.

X _C2 ＝R _C2-C1 X _C1 +T _C2-C1 (15)

Wherein: R _C2-C1 is the rotation matrix between X _C2 and X _C1 coordinate systems;

T _C2-C1 is the translation matrix between the X _C2 and X _C1 coordinate systems;

According to the previous derivation, we know that:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 16</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 17</span>}<span\; class="notranslate">\; )</span>$

In summary, the method for synchronous calibration of two cameras and a single projection light source designed in the present invention, the specific operation steps are as follows:

Step 1: Fix two color or black-and-white cameras and a projection light source (the resolution of the projection light source is L _R × L _C ) on the scanning platform, and determine that the color Or the positions of the black-and-white camera and the projection light source will not be changed, wherein the color or black-and-white camera placed on the left side of the projection light source is called the left camera, and the color or black-and-white camera placed on the right side of the projection light source is called the right camera. Camera, although there is only one projection light source, it can form a monocular three-dimensional measurement system with the left camera and the right camera. When the projection light source and the left camera form a three-dimensional measurement system, the projection light source is called the left projection light source , when the projection light source and the right camera form a three-dimensional measurement system, the projection light source is called the right projection light source, and the object space coordinate system is called the left object space coordinate system in the three-dimensional measurement system formed with the left camera, and the right camera constitutes The three-dimensional measurement system is called the right object space coordinate system; place the pre-processed calibration target at a position close to the measured object, that is, within the range of ±500mm from the measured object, and place the calibration target target, and make sure that the calibration target can be completely photographed by the two color or black-and-white cameras, and that the light signal range that can be projected by the projection light source can cover the location of the calibration target; adjust the The focal length of the two color or black-and-white cameras and the projection light source, so that it is in the best condition;

Step 2: Adjust the position of the calibration target more than 3 times, preferably 5-8 times, and ensure that each position of the calibration target can be adjusted by the two color or black and white The camera is fully photographed, and the light signal range that the projection light source can project can cover the position of the calibration target; each time the target is adjusted, the two color or black and white cameras must be used to perform target image capture. Collect and use the projection light source to project a series of gray code plus 6-step phase shift images to the calibration target, and collect each image projected by the projection light source through the two color or black and white cameras ;

Step 3: Using Zhang Zhengyou’s tablet calibration method, obtain the left camera coordinate system X _C1 , the right camera coordinate system X _C2 , the left projected light source coordinate system X _P1 , the right projected light source coordinate system X _P2 , the left object space coordinate system X _W1 and the right The coordinate relationship between the object space coordinate system X _W2 is shown in the following formula:

X _C1 =R ₁ X _W1 +T ₁ (18)

X _P1 =R ₂ X _W1 +T ₂ (19)

X _C2 =R ₃ X _W2 +T ₃ (20)

X _P2 =R ₄ X _W2 +T ₄ (21)

Step 4: Use the following formula to convert the right camera coordinate system to the left camera coordinate system to unify the coordinates of the two views:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; two</span>}<span\; class="notranslate">\; )</span>$

So far, the calibration process is over.

The flowchart of the synchronous calibration method for two cameras and a single projection light source designed by the present invention is shown in FIG. 2 .

The biggest difference between the present invention and the existing binocular vision calibration method is: the existing binocular vision system can only obtain the intersection of three-dimensional information captured by two cameras, and the measurement range is small; the binocular vision calibration method provided by the present invention , the union of the three-dimensional information captured by the two cameras can be obtained, the measurement range is large, and the measurement times can be reduced when measuring large objects.

In summary, the advantages of the bi-objective positioning method of the present invention are:

(1) The union of 3D measurement data from two perspectives can be obtained without increasing hardware costs;

(2) The coordinate relationship between the two cameras and the projection light source can be obtained synchronously, and the measurement range is better than the existing binocular vision measurement method;

The above schematically describes the present invention and its embodiments, and the description is not limiting, and what is shown in the drawings is only one of the embodiments of the present invention. Therefore, if a person of ordinary skill in the art is inspired by it, without departing from the inventive concept of the present invention, adopt other forms of similar components or other forms of layout of each component, without creatively designing a structure similar to the technical solution. The technical solutions and embodiments should all belong to the protection scope of the present invention.

Claims (1)

1. A binocular camera and a single projection light source synchronous calibration method, is characterized in that, comprises the following steps: Step 1: Fix two color or black-and-white cameras and a projection light source (the resolution of the projection light source is L _R × L _C ) on the scanning platform, and determine that the color Or the positions of the black-and-white camera and the projection light source will not be changed, wherein the color or black-and-white camera placed on the left side of the projection light source is called the left camera, and the color or black-and-white camera placed on the right side of the projection light source is called the right camera. Camera, although there is only one projection light source, it can form a monocular three-dimensional measurement system with the left camera and the right camera. When the projection light source and the left camera form a three-dimensional measurement system, the projection light source is called the left projection light source , when the projection light source and the right camera form a three-dimensional measurement system, the projection light source is called the right projection light source, and the object space coordinate system is called the left object space coordinate system in the three-dimensional measurement system formed with the left camera, and the right camera constitutes The three-dimensional measurement system is called the right object space coordinate system; place the pre-processed calibration target at a position close to the measured object, that is, within ±500mm from the measured object, and place the calibration target target, and make sure that the calibration target can be completely photographed by the two color or black-and-white cameras, and that the light signal range that can be projected by the projection light source can cover the location of the calibration target; adjust the The focal length of the two color or black-and-white cameras and the projection light source, so that it is in the best condition; Step 2: Adjust the position of the calibration target more than 3 times, preferably 5-8 times, and ensure that each position of the calibration target can be adjusted by the two color or black and white The camera is fully photographed, and the light signal range that the projection light source can project can cover the position of the calibration target; each time the target is adjusted, the two color or black and white cameras must be used to perform target image capture. Collect and use the projection light source to project a series of gray code plus 6-step phase shift images to the calibration target, and collect each image projected by the projection light source through the two color or black and white cameras ; Step 3: Using Zhang Zhengyou’s tablet calibration method, obtain the left camera coordinate system X _C1 , the right camera coordinate system X _C2 , the left projected light source coordinate system X _P1 , the right projected light source coordinate system X _P2 , the left object space coordinate system X _W1 and the right The coordinate relationship between the object space coordinate system X _W2 is shown in the following formula: X _C1 =R ₁ X _W1 +T ₁ (1) X _P1 =R ₂ X _W1 +T ₂ (2) X _C2 =R ₃ X _W2 +T ₃ (3) X _P2 =R ₄ X _W2 +T ₄ (4) Step 4: Use the following formula to convert the right camera coordinate system to the left camera coordinate system to unify the coordinates of the two views: ${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$ So far, the calibration process is over.

Images