CN113008163B - Encoding and decoding method based on frequency shift stripes in structured light three-dimensional reconstruction system - Google Patents
Encoding and decoding method based on frequency shift stripes in structured light three-dimensional reconstruction system Download PDFInfo
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Abstract
The invention discloses a coding and decoding method based on frequency shift stripes in a structured light three-dimensional reconstruction system, which comprises the steps of firstly generating a target stripe graph group according to target parameters, and coding projector image coordinates into the target stripe graph group, wherein the target parameters at least comprise the frequency shift amount and the frequency shift times N of the stripes, and the N is an integer which is more than or equal to 3; sequentially projecting the target stripe pattern group to a scene to be detected, and shooting projected images to obtain N first stripe patterns; and finally, decoding the image coordinates of the projector from the N first stripe images. Compared with the existing encoding and decoding method based on the phase shift fringes, the method disclosed by the invention can be used for calculating the projector image coordinate of each pixel independently in the decoding process, so that the method is not limited by any space prior information, and can be better suitable for complex scenes such as discontinuous surfaces.
Description
Technical Field
The invention belongs to the technical field of computer vision, and particularly relates to an encoding and decoding method.
Background
The structured light three-dimensional reconstruction technology is always a hotspot of research in the fields of three-dimensional computer vision, three-dimensional sensing and measurement, and is widely applied to the aspects of industrial detection, reverse engineering, human three-dimensional modeling, cultural relic protection and the like. The method has the characteristics of non-contact, non-damage, high speed, high precision and the like, so that the method becomes the most ideal means for accurate three-dimensional reconstruction and profile morphology measurement of scenes.
In the structured light three-dimensional reconstruction process, a projector or a light source projects a series of fringe patterns into a scene, then a camera shoots the fringe patterns reflected and modulated by the surface of the scene, the obtained fringe patterns are processed by a fringe analysis technology to obtain the phase of fringes, and then the fringe phase is converted into a three-dimensional reconstruction result according to a triangulation principle and known system parameters. The method comprises the steps of obtaining accurate fringe pattern phase based on a certain coding and decoding strategy, and obtaining corresponding projector image coordinates through calculation. At present, an encoding and decoding method based on single-frequency fringe projection is based on phase space continuity assumption, or accurate acquisition of image coordinates of a projector is realized by introducing a plurality of cameras or adopting a light field camera and the like. However, the former cannot adapt to a surface with steps because of the dependency relationship between adjacent pixels in the decoding process based on the assumption of phase space continuity, while the latter can implement independent encoding and decoding between pixels, but increases the system cost and complexity because of the addition of hardware. Compared with the prior art, the coding and decoding method based on the phase shift stripes can accurately and robustly acquire the image coordinates of the projector by projecting a plurality of stripe images with different frequencies and carrying out multiple phase shifts on the stripe images with each frequency, and adjacent pixels in the decoding process have independence and can be suitable for non-continuous surfaces. However, the efficiency of three-dimensional reconstruction is reduced due to the need to project and shoot a plurality of fringe patterns with different frequencies. Meanwhile, the methods are all based on a two-step strategy, namely, the wrapping phase is firstly obtained, then the wrapping phase is unwrapped based on an unwrapping algorithm to obtain a final result, and the operation is complicated.
In summary, a faster, simpler and simpler encoding and decoding method needs to be designed, so as to realize stable, robust and inter-pixel independent operation projector image coordinate encoding and decoding under the premise of requiring fewer fringe patterns and not needing to increase hardware. Therefore, it is necessary to develop a codec method capable of coordinating or solving the above problems.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a coding and decoding method based on frequency shift stripes in a structured light three-dimensional reconstruction system, which comprises the steps of firstly generating a target stripe graph group according to target parameters, coding projector image coordinates into the target stripe graph group, wherein the target parameters at least comprise the frequency shift amount and the frequency shift times N of the stripes, and the N is an integer which is greater than or equal to 3; sequentially projecting the target fringe pattern group to a scene to be detected, and shooting a projected image to obtain N first fringe patterns; and finally, decoding the image coordinates of the projector from the N first stripe images. Compared with the existing coding and decoding method based on the phase shift stripes, the invention calculates the projector image coordinate of each pixel independently in the decoding process, so that the method is not limited by any space prior information, and can better adapt to complex scenes such as discontinuous surfaces and the like.
The technical scheme adopted by the invention for solving the technical problem comprises the following steps:
the structured light three-dimensional reconstruction system comprises a computer, a projector and a camera; the projector and the camera are connected with the computer; the computer is used for generating a target fringe pattern group and decoding the image coordinates of the projector from a first fringe pattern shot by the camera; the projector is used for projecting a target fringe pattern group to a scene; the camera is used for shooting a target fringe pattern group reflected by the surface of a scene to obtain N fringe patterns, the fringe patterns shot by the camera are called as first fringe patterns, and N is an integer greater than or equal to 3;
step 1: defining parameters of a target fringe pattern group, generating the target fringe pattern group by a target computer according to the parameter coding of the target fringe pattern group, and simultaneously coding image coordinates of a projector into the target fringe pattern group, wherein the target fringe pattern group comprises N target fringe patterns;
defining the average brightness of the target stripe as A, the modulation degree of the target stripe as B, and the initial phase of the target stripe as
Initial frequency of target fringe is f 0 (ii) a The specific encoding steps are as follows:
step 1-1: generating a 1 st target fringe pattern by adopting a trigonometric function;
if the generated target fringe pattern is a vertical fringe pattern, encoding by adopting any one of the formula (1) and the formula (2):
if the generated target fringe pattern is a horizontal fringe pattern, encoding by adopting any one of the formulas (3) and (4):
wherein, I p1 (x p ,y p ) Is the 1 st target stripe pattern, x p As a coordinate of the horizontal direction of the projector image, x p ＝1,2,3,…,M p -1，M p The width of the target stripe image in the horizontal direction; y is p As a coordinate of the vertical direction of the projector image, y p ＝1,2,3,…,N p -1，N p The height of the target stripe pattern in the vertical direction is shown;
if the formula (1) is selected for coding, the formula (5), the formula (9) and the formula (13) are sequentially selected when the vertical stripe graph is calculated in the subsequent step; if the formula (2) is selected for encoding, the formula (6), the formula (10) and the formula (14) are sequentially selected when the vertical stripe pattern is calculated in the subsequent step;
if the formula (3) is selected for encoding, the formula (7), the formula (11) and the formula (15) are sequentially selected when the horizontal fringe pattern is calculated in the subsequent step; if the formula (4) is selected for encoding, the formula (8), the formula (12) and the formula (16) are sequentially selected when the horizontal fringe pattern is calculated in the subsequent step;
step 1-2: generating target fringe graphs from the 2 nd to the Nth;
the frequency of the (i + 1) th target fringe pattern is f 0 + i Δ f, Δ f is the amount of frequency shift, i ═ 1,2,3, …, N-1;
if the generated target fringe image is a vertical fringe image, selecting an equation (5) or an equation (6) according to the step 1-1 by the calculation formula of the (i + 1) th target fringe image:
if the generated target fringe image is a horizontal fringe image, selecting an equation (7) or an equation (8) according to the step 1-1 by the calculation formula of the (i + 1) th target fringe image:
and 2, step: the projector sequentially projects N target fringe patterns in the target fringe pattern group to a scene to be measured, the camera sequentially shoots the projected images to obtain N first fringe patterns, and the target fringe patterns and the first fringe patterns are in one-to-one correspondence;
and step 3: the computer decodes from N first stripe images to obtain the image coordinates of the projector;
step 3-1: assuming that each first fringe pattern in the N first fringe patterns comprises H multiplied by W pixel points; the coordinates of the pixel points are represented by (p, q), wherein p is 1,2,3, …, H, q is 1,2,3, …, W; the coordinates of the pixel points at the same position in each first stripe image are the same as the coordinates of the pixel points at the same position in the other N-1 first stripe images;
step 3-2: with pixels as units, decoding projector image coordinates of each pixel point in H multiplied by W pixel points pixel by pixel from N first stripe images;
step 3-2-1: establishing a tth parameter estimation equation related to a jth pixel point in the first fringe image according to the image brightness of the jth pixel point in the tth first fringe image, wherein t is 1,2,3, …, N, j is 1,2,3, … and H multiplied by W;
if the target fringe image corresponding to the first fringe image in the t-th frame is a vertical fringe image, selecting an expression (9) or an expression (10) according to the step 1-1 by using the parameter estimation equation:
if the target fringe image corresponding to the first fringe image in the t-th frame is a horizontal fringe image, selecting an equation (11) or an equation (12) according to the step 1-1 by using the parameter estimation equation:
wherein, I ct (p, q) is the image brightness of the jth pixel point in the tth first stripe image, A c Representing the average brightness of the stripes as the parameters to be estimated; b is c Representing the modulation degree of the stripes as parameters to be estimated; (x' p ，y′ p ) The projector image coordinate corresponding to the jth pixel point in the tth first stripe image;
step 3-2-2: obtaining the parameter estimation equations of the jth pixel point in the 1 st to Nth first stripe images, N in total, and simultaneously obtaining N parameter estimation equations to solve the parameter A to be estimated at the jth pixel c 、B c And (x' p ，y′ p )；
Establishing an optimization objective function:
if the target fringe pattern corresponding to the first fringe pattern is a vertical fringe pattern, selecting the optimization objective function E (A) of the formula (13) or the formula (14) according to the step 1-1 c ,B c ,x′ p ) Minimum, solving N parameter estimation equations to obtain (x' p ，y′ p ) The image coordinate of the projector corresponding to the jth pixel point in the first fringe image is obtained;
if the target fringe pattern corresponding to the first fringe pattern is a horizontal fringe pattern, the optimization objective function E (A) of the formula (15) or the formula (16) is selected according to the step 1-1 c ,B c ,y′ p ) Minimum, solving N parameter estimation equations to obtain (x' p ，y′ p ) The image coordinate of the projector corresponding to the jth pixel point in the first fringe image is obtained;
step 3-2-3: and repeating the step 3-2-1 and the step 3-2-2 to obtain projector image coordinates corresponding to all pixel points in the first fringe pattern.
Preferably, the method for establishing the optimization objective function in the step 3-2-2 is a least square method.
The invention has the following beneficial effects:
compared with the existing encoding and decoding method based on the phase shift fringe, the target fringe pattern group generated according to the frequency shift quantity and the frequency shift times is adopted, the periodicity in the projector image coordinate decoding process can be eliminated by the frequency shift quantity and the frequency shift times, so that the corresponding projector image coordinate can be directly obtained without phase unwrapping, and the frequency shift times N can be 3 at the minimum theoretically, and the number of the required fringe patterns is less than that of a multi-frequency conventional phase shift fringe pattern, so that the efficiency is higher; in addition, compared with other space phase unwrapping methods, the method provided by the invention can be used for independently calculating the projector image coordinate of each pixel in the decoding process, so that the method is not limited by any space prior information, and can be better suitable for complex scenes such as discontinuous surfaces.
Drawings
Fig. 1 is a schematic diagram of a structured light three-dimensional reconstruction system according to the present invention.
FIG. 2 is a flow chart of the method of the present invention.
Fig. 3 is a schematic diagram of design parameters required by the frequency-shifted fringe pattern set generated by the present invention.
FIG. 4 is a schematic diagram of a set of frequency-shifted fringe patterns generated by the present invention: FIG. 4(A) is a frequency-shifted fringe pattern with a vertical fringe pattern; fig. 4(B) is a frequency-shifted fringe pattern with a horizontal fringe pattern.
Fig. 5 is an example of a set of N-step frequency-shifted stripes with a vertical stripe pattern of the present invention when N is 4: fig. 5(a) to 5(D) are 1,2,3, and 4-step frequency-shift stripe patterns, respectively; fig. 5(E) is a section line of the 1,2,3, 4-th step frequency shift stripe pattern.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
As shown in fig. 2, a coding and decoding method based on frequency shift stripes in a structured light three-dimensional reconstruction system includes the following steps:
as shown in fig. 1, the structured light three-dimensional reconstruction system comprises a computer, a projector and a camera; the projector and the camera are connected with the computer; the computer is used for generating a target fringe pattern group and decoding the image coordinates of the projector from a first fringe pattern shot by the camera; the projector is used for projecting a target fringe pattern group to a scene; the camera is used for shooting a target fringe pattern group reflected by the surface of a scene to obtain N fringe patterns, the fringe patterns shot by the camera are called as first fringe patterns, and N is an integer greater than or equal to 3;
step 1: defining parameters of a target fringe pattern group, generating the target fringe pattern group by a target computer according to the parameter coding of the target fringe pattern group, and simultaneously coding image coordinates of a projector into the target fringe pattern group, wherein the target fringe pattern group comprises N target fringe patterns;
as shown in fig. 3, the average brightness of the target stripe is defined as a, the modulation degree of the target stripe is defined as B, and the initial phase of the target stripe is defined as
Initial frequency of target fringe is f 0 (ii) a The specific encoding steps are as follows:
step 1-1: generating a 1 st target fringe pattern by adopting a trigonometric function;
as shown in fig. 4, if the generated target fringe pattern is a vertical fringe pattern, encoding is performed by using any one of the following equations (1) and (2):
if the generated target fringe pattern is a horizontal fringe pattern, encoding is performed by adopting any one of the formula (3) and the formula (4):
wherein, I p1 (x p ,y p ) Is the 1 st target stripe pattern, x p As a coordinate of the horizontal direction of the projector image, x p ＝1,2,3,…,M p -1，M p The width of the target stripe image in the horizontal direction; y is p As the coordinate of the vertical direction of the projector image, y p ＝1,2,3,…,N p -1，N p The height of the target stripe pattern in the vertical direction is shown;
if the formula (1) is selected for coding, the formula (5), the formula (9) and the formula (13) are sequentially selected when the vertical stripe graph is calculated in the subsequent step; if the formula (2) is selected for encoding, the formula (6), the formula (10) and the formula (14) are sequentially selected when the vertical fringe pattern is calculated in the subsequent step;
if the formula (3) is selected for encoding, the formula (7), the formula (11) and the formula (15) are sequentially selected when the horizontal fringe pattern is calculated in the subsequent step; if the formula (4) is selected for encoding, the formula (8), the formula (12) and the formula (16) are sequentially selected when the horizontal fringe pattern is calculated in the subsequent step;
step 1-2: generating target fringe graphs from the 2 nd to the Nth;
the frequency of the (i + 1) th target fringe pattern is f 0 + i Δ f, Δ f is the amount of frequency shift, i ═ 1,2,3, …, N-1;
if the generated target fringe image is a vertical fringe image, selecting an equation (5) or an equation (6) according to the step 1-1 by the calculation formula of the (i + 1) th target fringe image:
if the generated target fringe pattern is a horizontal fringe pattern, the calculation formula of the (i + 1) th target fringe pattern selects the formula (7) or the formula (8) according to the step 1-1:
and 2, step: the projector sequentially projects N target fringe patterns in the target fringe pattern group to a scene to be measured, the camera sequentially shoots the projected images to obtain N first fringe patterns, and the target fringe patterns and the first fringe patterns are in one-to-one correspondence;
and step 3: the computer decodes from N first stripe images to obtain the image coordinates of the projector;
step 3-1: assuming that each first fringe pattern in the N first fringe patterns comprises H multiplied by W pixel points; the coordinates of the pixel points are represented by (p, q), wherein p is 1,2,3, …, H, q is 1,2,3, …, W; the coordinates of the pixel points at the same position in each first stripe image are the same as the coordinates of the pixel points at the same position in the other N-1 first stripe images;
step 3-2: with pixels as units, decoding projector image coordinates of each pixel point in H multiplied by W pixel points pixel by pixel from N first stripe images;
step 3-2-1: establishing a tth parameter estimation equation related to a jth pixel point in the first fringe image according to the image brightness of the jth pixel point in the tth first fringe image, wherein t is 1,2,3, …, N, j is 1,2,3, … and H multiplied by W;
if the target fringe image corresponding to the first fringe image in the t-th frame is a vertical fringe image, selecting an expression (9) or an expression (10) according to the step 1-1 by using the parameter estimation equation:
if the target fringe pattern corresponding to the first fringe pattern in the t-th frame is a horizontal fringe pattern, selecting an expression (11) or an expression (12) according to the step 1-1 by using the parameter estimation equation:
wherein, I ct (p, q) is the image brightness of the jth pixel point in the tth first stripe image, A c Representing the average brightness of the stripes as the parameters to be estimated; b is c Representing the modulation degree of the stripes as parameters to be estimated; (x' p ，y′ p ) For the jth image in the tth first stripe imageProjector image coordinates corresponding to the pixel points;
step 3-2-2: obtaining the parameter estimation equations of the jth pixel point in the 1 st to Nth first stripe graphs, N in total, and simultaneously obtaining N parameter estimation equations to solve the parameter A to be estimated at the jth pixel point c 、B c And (x' p ，y′ p )；
The parameter estimation equation establishment processes of each pixel point are mutually independent, namely the projector image coordinate decoding processes of any two different pixels are independent, and the decoding process is not constrained by spatial smoothness prior information, so that the method is very suitable for three-dimensional reconstruction of discontinuous surfaces.
And (3) establishing an optimized objective function by adopting a least square or other optimization algorithm:
if the target fringe pattern corresponding to the first fringe pattern is a vertical fringe pattern, selecting the optimization objective function E (A) of formula (13) or formula (14) according to step 1-1 c ,B c ,x′ p ) Minimum, solving N parameter estimation equations to obtain (x' p ，y′ p ) The image coordinate of the projector corresponding to the jth pixel point in the first stripe image is obtained;
if the target fringe pattern corresponding to the first fringe pattern is a horizontal fringe pattern, the optimization objective function E (A) of the formula (15) or the formula (16) is selected according to the step 1-1 c ,B c ,y′ p ) Minimum, solving N parameter estimation equations to obtain (x' p ，y′ p ) The image coordinate of the projector corresponding to the jth pixel point in the first fringe image is obtained;
step 3-2-3: and repeating the step 3-2-1 and the step 3-2-2, and calculating to obtain a group of parameters to be estimated with the minimum optimization objective function, namely the solution result of the equation set, wherein the image coordinates of the projector in the result are the decoding result. And obtaining the projector image coordinates corresponding to all the pixel points in the first stripe image.
According to the established optimization objective function, because a fixed period T does not exist, the image coordinate of the projector is added or subtracted with the period T, and the value of the optimization objective function is kept unchanged, namely only one unique solution can be formed in an equation set formed by simultaneous N parameter estimation equations, the method does not have the phase wrapping problem, and can directly decode the image coordinate of the projector without calculating the phase of the stripes to convert the phase of the stripes to obtain a decoding result. Meanwhile, theoretically, only three parameters to be estimated are included in an equation set formed by the simultaneous N parameter estimation equations, so that the equation set can be solved by at least three parameter estimation equations, namely the minimum number N of the required fringe patterns is 3; the number of the fringe patterns required for acquiring the wrapping phase by the phase-shifting fringe pattern is 3, and at least 6 fringe patterns are required to obtain the final decoding result by adding the fringe patterns with at least two frequencies. In comparison, theoretically, the coding and decoding method based on the frequency shift stripes needs fewer stripe patterns, so that the efficiency is higher, and the method is more suitable for the three-dimensional reconstruction of a rapid and dynamic scene.
An experiment is performed by taking N-4, and the experimental result is as shown in fig. 5, which is an example of a group of N-step frequency shift fringe patterns when N-4 is used with a vertical fringe pattern: fig. 5(a) to 5(D) are i-th to 1,2,3, 4-th step frequency-shift stripe diagrams, respectively; fig. 5(E) is a section line of the i-th-1, 2,3, 4-step frequency shift stripe pattern.
As can be seen from the figure, the method achieves better effect.
Claims (2)
1. A coding and decoding method based on frequency shift stripes in a structured light three-dimensional reconstruction system is characterized in that the structured light three-dimensional reconstruction system comprises a computer, a projector and a camera; the projector and the camera are connected with the computer; the computer is used for generating a target fringe pattern group and decoding the image coordinates of the projector from a first fringe pattern shot by the camera; the projector is used for projecting a target fringe pattern group to a scene; the camera is used for shooting a target fringe pattern group reflected by the surface of a scene to obtain N fringe patterns, the fringe patterns shot by the camera are called as first fringe patterns, and N is an integer greater than or equal to 3; the method comprises the following steps:
step 1: defining parameters of a target fringe pattern group, generating the target fringe pattern group by a target computer according to the parameter coding of the target fringe pattern group, and simultaneously coding image coordinates of a projector into the target fringe pattern group, wherein the target fringe pattern group comprises N target fringe patterns;
defining the average brightness of the target stripe as A, the modulation degree of the target stripe as B, and the initial phase of the target stripe as
Initial frequency of target fringe is f 0 (ii) a The specific encoding steps are as follows:
step 1-1: generating a 1 st target fringe pattern by adopting a trigonometric function;
if the generated target fringe pattern is a vertical fringe pattern, encoding by adopting any one of the formula (1) and the formula (2):
if the generated target fringe pattern is a horizontal fringe pattern, encoding is performed by adopting any one of the formula (3) and the formula (4):
wherein, I p1 (x p ,y p ) Is the 1 st target stripe image, x p As a coordinate of the horizontal direction of the projector image, x p ＝1,2,3,…,M p -1，M p The width of the target stripe image in the horizontal direction; y is p As the coordinate of the vertical direction of the projector image, y p ＝1,2,3,…,N p -1，N p The height of the target stripe pattern in the vertical direction is shown;
if the formula (1) is selected for coding, the formula (5), the formula (9) and the formula (13) are sequentially selected when the vertical stripe graph is calculated in the subsequent step; if the formula (2) is selected for encoding, the formula (6), the formula (10) and the formula (14) are sequentially selected when the vertical stripe pattern is calculated in the subsequent step;
if the formula (3) is selected for encoding, the formula (7), the formula (11) and the formula (15) are sequentially selected when the horizontal fringe pattern is calculated in the subsequent step; if the formula (4) is selected for encoding, the formula (8), the formula (12) and the formula (16) are sequentially selected when the horizontal fringe pattern is calculated in the subsequent step;
step 1-2: generating target fringe graphs from the 2 nd to the Nth;
the frequency of the (i + 1) th target fringe pattern is f 0 + i Δ f, Δ f is the amount of frequency shift, i ═ 1,2,3, …, N-1;
if the generated target fringe pattern is a vertical fringe pattern, selecting formula (5) or formula (6) according to step 1-1 for the calculation formula of the (i + 1) th target fringe pattern:
if the generated target fringe pattern is a horizontal fringe pattern, the calculation formula of the (i + 1) th target fringe pattern selects the formula (7) or the formula (8) according to the step 1-1:
and 2, step: the projector sequentially projects N target fringe patterns in the target fringe pattern group to a scene to be measured, the camera sequentially shoots the projected images to obtain N first fringe patterns, and the target fringe patterns and the first fringe patterns are in one-to-one correspondence;
and step 3: the computer decodes from N first stripe pictures to obtain the image coordinate of the projector;
step 3-1: assuming that each first fringe pattern in the N first fringe patterns comprises H multiplied by W pixel points; the coordinates of the pixel points are represented by (p, q), wherein p is 1,2,3, …, H, q is 1,2,3, …, W; the coordinates of the pixel points at the same position in each first stripe image are the same as the coordinates of the pixel points at the same position in the other N-1 first stripe images;
step 3-2: with pixels as units, decoding projector image coordinates of each pixel point in H multiplied by W pixel points pixel by pixel from N first stripe images;
step 3-2-1: establishing a tth parameter estimation equation related to a jth pixel point in the first fringe image according to the image brightness of the jth pixel point in the tth first fringe image, wherein t is 1,2,3, …, N, j is 1,2,3, … and H multiplied by W;
if the target fringe pattern corresponding to the first fringe pattern in the t-th frame is a vertical fringe pattern, selecting an expression (9) or an expression (10) according to the step 1-1 by using the parameter estimation equation:
if the target fringe pattern corresponding to the first fringe pattern in the t-th frame is a horizontal fringe pattern, selecting an expression (11) or an expression (12) according to the step 1-1 by using the parameter estimation equation:
wherein, I ct (p, q) is the image brightness of the jth pixel point in the tth first stripe image, A c Representing the average brightness of the stripes as the parameters to be estimated; b is c Representing the modulation degree of the stripes as parameters to be estimated; (x' p ，y′ p ) The projector image coordinate corresponding to the jth pixel point in the tth first stripe image;
step 3-2-2: obtaining the parameter estimation equations of the jth pixel point in the 1 st to Nth first stripe images, N in total, and simultaneously obtaining N parameter estimation equations to solve the parameter A to be estimated at the jth pixel c 、B c And (x' p ，y′ p )；
Establishing an optimization objective function:
if the target fringe pattern corresponding to the first fringe pattern is a vertical fringe pattern, selecting the optimization objective function E (A) of formula (13) or formula (14) according to step 1-1 c ,B c ,x′ p ) Minimum, solving N parameter estimation equations to obtain (x' p ，y′ p ) The image coordinate of the projector corresponding to the jth pixel point in the first fringe image is obtained;
if the target fringe pattern corresponding to the first fringe pattern is a horizontal fringe pattern, the optimization objective function E (A) of the formula (15) or the formula (16) is selected according to the step 1-1 c ,B c ,y′ p ) Minimum, solving N parameter estimation equations to obtain (x' p ，y′ p ) The image coordinate of the projector corresponding to the jth pixel point in the first fringe image is obtained;
step 3-2-3: and repeating the step 3-2-1 and the step 3-2-2 to obtain projector image coordinates corresponding to all pixel points in the first fringe pattern.
2. The encoding and decoding method based on frequency-shift fringes in the structured light three-dimensional reconstruction system according to claim 1, wherein the method for establishing the optimized objective function in step 3-2-2 is a least square method.
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