A phase shift error self-correction method and system based on active phase difference mapping

Abstract

The application provides a phase shift error self-correction method and system based on active phase difference mapping, and relates to the technical field of optics. The method is based on phase shift fringes, and uses an iterative algorithm to obtain an iterated background light intensity and a modulation degree. Based on the iterated background light intensity and the modulation degree, the adjusted phase shift fringe intensity is determined through adjustment. Based on the adjusted phase shift fringe intensity, a first mapping curve is obtained by using an active phase difference mapping algorithm. Based on the first mapping curve, a second mapping curve is obtained through simulation. By using the first mapping curve and the second mapping curve, the corresponding phase shift amount is obtained through calculation. It is judged whether the phase shift amount satisfies an iteration condition. If not, the method returns to S1. If yes, the phase shift amount is taken as a phase shift amount result, and a corrected phase distribution is determined. The application realizes high-precision phase shift error self-correction and has high universality.

Description

Technical Field

[0001] This specification relates to the field of optical technology, and in particular to a phase shift error self-correction method and system based on active phase difference mapping. Background Technology

[0002] Optical 3D sensing technology provides an efficient and accurate means for precision measurement and model building, and is widely used in industrial manufacturing, modern medicine, cultural relic preservation, virtual reality, and other fields, profoundly impacting how people perceive and interact with the world. Fringe projection profilometry is a typical optical 3D measurement technique that mainly obtains the 3D information of an object's surface by projecting phase-shifted fringes. Therefore, accurate phase shift is of great significance for high-precision measurement results.

[0003] Both mechanical phase-shifting systems and interferometric measurement systems employing non-digital projection face a significant challenge—phase shift error. Phase shift error, primarily caused by initial errors, component wear, or accuracy issues, introduces periodic phase errors into the measurement results, affecting the final measurement accuracy. Furthermore, phase shift error is not constant and may change with factors such as the degree of wear. Therefore, self-correction of phase shift error is a crucial issue in non-digital fringe projection systems. Summary of the Invention

[0004] To address the aforementioned shortcomings in existing technologies, this invention provides a phase shift error self-correction method and system based on active phase difference mapping, achieving high-precision phase shift error self-correction and providing a more universal solution to phase shift error problems in the field of optical technology.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention is: a phase shift error self-correction method based on active phase difference mapping, comprising:

[0006] S1: Based on phase-shifting fringes, the background light intensity and modulation index are obtained using an iterative algorithm;

[0007] S2: Based on the background light intensity and modulation degree after the iteration, the intensity of the adjusted phase-shifted fringes is determined by adjustment;

[0008] S3: Based on the adjusted phase shift fringe intensity, the first mapping curve is obtained using an active phase difference mapping algorithm;

[0009] S4: Based on the first mapping curve, the second mapping curve is obtained through simulation;

[0010] S5: Using the first and second mapping curves, the corresponding phase shift is obtained through calculation;

[0011] S6: Determine whether the phase shift satisfies the iteration condition. If not, return to S1. If yes, use the phase shift as the phase shift result to determine the corrected phase distribution.

[0012] The beneficial effects of this invention are as follows: the processor can utilize iterative algorithms and active phase difference mapping algorithms to achieve phase shift error self-correction and obtain the corrected phase distribution. In this way, the influence of object height distribution and incomplete periodic phase distribution on correction accuracy can be eliminated, achieving high-precision phase shift error self-correction even under measurement conditions using low-density fringes. This method is applicable to various fringe types, providing a more universal solution to phase shift error problems in the field of optical technology.

[0013] Furthermore: the iterative expressions for background light intensity and modulation degree are specifically as follows:

[0014]

[0015] in,[·] -1 This represents finding the inverse of a matrix, A. k Indicates the result after the k-th iteration Background light intensity, Indicates the result after the k-th iteration The cosine value of the modulation system, Indicates the result after the k-th iteration The sine value of the modulation system, This represents the cosine value of the first phase shift in the (k-1)th iteration. This represents the sine value of the first phase shift in the (k-1)th iteration. This represents the cosine value of the second phase shift in the (k-1)th iteration. This represents the sine value of the second phase shift in the (k-1)th iteration. This indicates the intensity of the phase shift fringes in the first frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the second frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the third frame actually captured by the camera.

[0016] Furthermore: the adjusted expression for the phase-shifted fringe intensity is specifically as follows:

[0017]

[0018] in, Indicates according to and The adjusted stripes in frame n+1. This represents the stripe in the (n+1)th frame actually captured by the camera. This represents the average background light intensity. This represents the mean of the adjustment system. Represents phase information, δ n This represents the phase shift of the stripes in the (n+1)th frame.

[0019] Further: S3 includes:

[0020] S310: Based on the adjusted phase-shift fringe intensity, determine the original phase distribution and the phase distribution after active phase shift using a formula;

[0021] S320: Determine the active phase difference by calculating the difference between the phase distribution after active phase shift and the original phase distribution;

[0022] S330: Based on the phase distribution after the active phase shift and the active phase difference, the first mapping curve is obtained using the active phase difference mapping algorithm.

[0023] In some embodiments of this specification, the processor obtains a first mapping curve based on the adjusted phase-shift fringe intensity using an active phase difference mapping algorithm. This method yields a more accurate first mapping curve, improving correction precision, and is unaffected by object height distribution or the completeness of the fringe's phase distribution and period, making it suitable for a wider range of measurement conditions.

[0024] Furthermore: the expression for the active phase difference mapping algorithm is specifically as follows:

[0025]

[0026]

[0027]

[0028]

[0029] Where G1 represents the first mapping curve, express and The mapping relationship, Represents the original phase distribution. This represents the phase distribution after active phase shifting. ε represents the active phase difference, and ε represents the active phase shift. This indicates the adjusted stripe intensity of the first frame. This indicates the adjusted stripe intensity for the second frame. P represents the adjusted stripe intensity of the 3rd frame. 11 P 12 P 13 P 14 P 15 P 21 P 22P 23 P 24 and P 25 All of these represent the corresponding active phase difference coefficients; the active phase difference coefficients can be determined by looking up the active phase difference coefficient table.

[0030] Further: S4 includes:

[0031] S410: Construct the initial second mapping curve;

[0032] S420: Based on the initial second mapping curve, a search is performed, and the curve with the highest similarity to the first mapping curve is taken as the corresponding second mapping curve.

[0033] Furthermore: the expression for the phase shift is specifically as follows:

[0034]

[0035]

[0036] Where (δ1,δ2) m Let F represent the phase shift obtained in the m-th search, where δ1 represents the first phase shift, δ2 represents the second phase shift, and F represents the second phase shift. obj This represents the objective function to be searched.

[0037] This specification provides one or more embodiments of a phase shift error self-correction system based on active phase difference mapping, including an acquisition module, a determination module, a first mapping module, a second mapping module, an analysis module, and a judgment module.

[0038] The acquisition module is used to obtain the background light intensity and modulation degree after iteration based on the phase-shifting fringes using an iterative algorithm;

[0039] The determining module is used to determine the adjusted phase-shift fringe intensity based on the iterated background light intensity and modulation degree.

[0040] The first mapping module is used to obtain a first mapping curve based on the adjusted phase shift fringe intensity using an active phase difference mapping algorithm;

[0041] The second mapping module is used to obtain a second mapping curve through simulation based on the first mapping curve;

[0042] The analysis module is used to calculate the corresponding phase shift using the first and second mapping curves.

[0043] The judgment module is used to determine whether the phase shift satisfies the iteration condition. If not, it returns to the acquisition module; if so, the phase shift is used as the phase shift result to determine the corrected phase distribution. Attached Figure Description

[0044] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0045] Figure 1 This is a schematic diagram of a phase shift error self-correction system based on active phase difference mapping, as shown in some embodiments of this specification.

[0046] Figure 2 This is an exemplary flowchart illustrating a phase shift error self-correction method based on active phase difference mapping according to some embodiments of this specification;

[0047] Figure 3 This is a schematic diagram of the nonlinear phase error introduced under several phase shift error conditions according to some embodiments of this specification, and the corresponding active phase difference mapping (APDM) curves.

[0048] Figure 4 This is a schematic diagram of APDM curves corresponding to different types of stripes according to some embodiments of this specification;

[0049] Figure 5 This is a schematic diagram showing the distribution of the objective function value for phase shift searching according to some embodiments of this specification. Detailed Implementation

[0050] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0051] Example 1

[0052] Figure 1 This is a schematic diagram of a phase shift error self-correction system based on active phase difference mapping, as shown in some embodiments of this specification.

[0053] In some embodiments, the phase shift error self-correction system 100 based on active phase difference mapping may include an acquisition module 110, a determination module 120, a first mapping module 130, a second mapping module 140, an analysis module 150, and a judgment module 160.

[0054] Module 110 is used to obtain the iterative background light intensity and modulation depth based on phase-shifting fringes using an iterative algorithm. More details regarding the iterative background light intensity and modulation depth can be found in [link to relevant documentation]. Figure 2 And its related descriptions.

[0055] The determination module 120 is used to determine the adjusted phase-shift fringe intensity based on the iterative background light intensity and modulation depth. More details regarding the adjusted phase-shift fringe intensity can be found in [link to relevant documentation]. Figure 2 And its related descriptions.

[0056] The first mapping module 130 is used to obtain a first mapping curve based on the adjusted phase shift fringe intensity using an active phase difference mapping algorithm. More details about the first mapping curve can be found in [link to relevant documentation]. Figure 2 And its related descriptions.

[0057] The second mapping module 140 is used to obtain a second mapping curve through simulation based on the first mapping curve. More details about the second mapping curve can be found in [link to relevant documentation]. Figure 2 And its related descriptions.

[0058] Analysis module 150 is used to calculate the corresponding phase shift using the first and second mapping curves. More details regarding the phase shift can be found in [link to relevant documentation]. Figure 2 And its related descriptions.

[0059] The judgment module 160 is used to determine whether the phase shift satisfies the iteration condition. If not, it returns to the acquisition module; if so, it uses the phase shift as the phase shift result to determine the corrected phase distribution. More details about the corrected phase distribution can be found in [link to relevant documentation]. Figure 2 And its related descriptions.

[0060] In some embodiments, a phase shift error self-correction system based on active phase difference mapping can be used to execute a phase shift error self-correction method based on active phase difference mapping, including: S1: Based on phase shift fringes, using an iterative algorithm, obtain the iterative background light intensity and modulation degree; S2: Based on the iterative background light intensity and modulation degree, determine the adjusted phase shift fringe intensity by adjustment; S3: Based on the adjusted phase shift fringe intensity, using an active phase difference mapping algorithm, obtain a first mapping curve; S4: Based on the first mapping curve, obtain a second mapping curve by simulation; S5: Using the first mapping curve and the second mapping curve, calculate the corresponding phase shift amount; S6: Determine whether the phase shift amount satisfies the iteration condition; if not, return to S1; if yes, use the phase shift amount as the phase shift amount result to determine the corrected phase distribution.

[0061] In some embodiments of this specification, the processor utilizes an active phase difference mapping-based phase shift error self-correction system to execute an active phase difference mapping-based phase shift error self-correction method. This approach eliminates the influence of object height distribution and incomplete periodic phase distribution on correction accuracy, achieving high-precision phase shift error self-correction even under low-density fringe measurement conditions. This method is applicable to various fringe types, providing a more universal solution to phase shift error problems in the field of optical technology.

[0062] Example 2

[0063] Figure 2 This is an exemplary flowchart illustrating a phase shift error self-correction method based on active phase difference mapping, according to some embodiments of this specification. Figure 2 As shown, process 200 includes the following steps. In some embodiments, process 200 may be executed by a processor.

[0064] S1: Based on phase-shifting fringes, the background light intensity and modulation index are obtained using an iterative algorithm.

[0065] The background light intensity and modulation index after iteration are the measured and adjusted phase-shifted fringe intensity parameters after iteration.

[0066] In some embodiments, the processor can determine the iterative background light intensity and modulation based on a formula:

[0067]

[0068] in,[·] -1 This represents finding the inverse of a matrix, A. k Indicates the result after the k-th iteration Background light intensity, Indicates the result after the k-th iteration The cosine value of the modulation system, Indicates the result after the k-th iteration The sine value of the modulation system, This represents the cosine value of the first phase shift in the (k-1)th iteration. This represents the sine value of the first phase shift in the (k-1)th iteration. This represents the cosine value of the second phase shift in the (k-1)th iteration. This represents the sine value of the second phase shift in the (k-1)th iteration. This indicates the intensity of the phase shift fringes in the first frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the second frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the third frame actually captured by the camera.

[0069] In some embodiments, the initial phase shift can be set to

[0070] In some embodiments, the adjusted phase shift fringe intensity of the (n+1)th frame actually captured by the camera after the k-th iteration The modulation mechanism can be expressed as:

[0071]

[0072] Among them, B k Indicates the result after the k-th iteration The modulus of sqrt is used to find the square root.

[0073] In some embodiments, the processor can access A k and B k The mean value is calculated, and the result is used as the corresponding background light intensity and modulation index for this iteration.

[0074] S2: Based on the iterative background light intensity and modulation, the adjusted phase-shift fringe intensity is determined by adjustment.

[0075] Phase-shift fringe intensity is data reflecting the intensity of phase-shift fringes.

[0076] In some embodiments, the processor can determine the adjusted phase-shift fringe intensity based on a formula:

[0077]

[0078] in, Indicates according to and The adjusted stripes in frame n+1. This represents the stripe in the (n+1)th frame actually captured by the camera. This represents the average background light intensity. This represents the mean of the adjustment system. Represents phase information, δ n This represents the phase shift of the stripes in the (n+1)th frame.

[0079] S3: Based on the adjusted phase shift fringe intensity, the first mapping curve is obtained using the Active Phase Difference Mapping Algorithm (APDM model).

[0080] The first mapping curve is a curve that reflects the actual phase shift information.

[0081] In some embodiments, the processor may implement S3 based on the following steps: S310: Based on the intensity of the phase shift fringe, determine the original phase distribution and the phase distribution after active phase shift using a formula; S320: Determine the active phase difference by calculating the difference between the phase distribution after active phase shift and the original phase distribution; S330: Based on the phase distribution after active phase shift and the active phase difference, obtain a first mapping curve using an active phase difference mapping algorithm.

[0082] In some embodiments, the processor may determine the first mapping curve based on a formula of the APDM model:

[0083]

[0084]

[0085]

[0086]

[0087] Where G1 represents the first mapping curve, express and The mapping relationship, Represents the original phase distribution. This represents the phase distribution after active phase shifting. ε represents the active phase difference, and ε represents the active phase shift. This indicates the adjusted stripe intensity of the first frame. This indicates the adjusted stripe intensity for the second frame. This indicates the adjusted stripe intensity of the 3rd frame. P represents phase information. 11 P 12 P 13 P 14 P 15 P 21 P 22 P 23 P 24 and P 25 This represents the corresponding active phase difference coefficient; the active phase difference coefficient can be determined by looking up the active phase difference coefficient table.

[0088] In some embodiments, such as Figure 3 As shown, the APDM curve can reflect phase shift error information.

[0089] In some embodiments, such as Figure 4 As shown, the APDM curve is independent of the stripe type, and the algorithm can be applied to different types of stripe patterns. This represents the phase distribution after active phase shifting.

[0090] In some embodiments, the processor can set the active phase shift ε to

[0091] In some embodiments, the processor may set the active phase difference coefficient table based on the following formula:

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] P 21 =1-2cos(π / 3-ε)+cos(δ1)[2cos(2π / 3-ε)-1]-2cos(δ2)+cos(δ2-δ1)[2+2cos(ε)];

[0098]

[0099]

[0100] P 24 =2+cos(δ1)[2cos(2π / 3-ε)-1]-2cos(δ2)-cos(δ1+δ2)[2+2cos(ε)]-2cos(π / 3-ε)cos(2δ1)-cos(2δ2);

[0101] P 25 =sin(δ1)[1-2cos(2π / 3-ε)]-2sin(δ2)+2cos(π / 3-ε)sin(2δ1)+sin(2δ2)-sin(δ1+δ2)[2+2cos(ε)];

[0102] Where δ1 represents the first phase shift, ε represents the active phase shift, δ2 represents the second phase shift, A represents the background intensity of the fringe, and B represents the modulation degree of the fringe.

[0103] In some embodiments, δ1, δ2, ε are related to stripe contrast. It is related to the reciprocal.

[0104] In some embodiments of this specification, the processor obtains a first mapping curve based on the adjusted phase shift fringe intensity using an active phase difference mapping algorithm. This method yields a more accurate first mapping curve, improving the accuracy of the correction.

[0105] S4: Based on the first mapping curve, the second mapping curve is obtained through simulation.

[0106] The second mapping curve is a curve that reflects the phase shift information of the first mapping curve.

[0107] In some embodiments, the processor can use the APDM model to process the intensity of the adjusted phase shift fringe before adjustment to obtain the second mapping curve corresponding to the first mapping curve of the round.

[0108] In some embodiments, the initial curve of the second mapping curve is obtained by simulating ideal phase shift fringes. The processor can filter the subsequent curves obtained after substituting different phase shift amounts and take the curve with the highest similarity to the first mapping curve as the corresponding second mapping curve.

[0109] In some embodiments, the processor may implement S4 based on the following steps: S410: constructing an initial second mapping curve; S420: searching based on the initial second mapping curve and taking the curve with the highest similarity to the first mapping curve as the corresponding second mapping curve.

[0110] The initial second mapping curve is a simulated curve that reflects the initial phase shift.

[0111] In some embodiments, the processor may use a particle swarm optimization algorithm to process the first mapping curve and obtain a second mapping curve by randomly generating particles.

[0112] In some embodiments, the processor may construct an initial second mapping curve based on the adjusted phase shift fringe intensity using an active phase difference mapping algorithm.

[0113] In some embodiments, the processor can use the Nelder-Mead algorithm to search the parameter space of the geometric transformation of the simplex based on the initial second mapping curve, and obtain multiple candidate second mapping curves.

[0114] In some embodiments, the processor can use the Nelder-Mead algorithm to determine the curve with the same phase shift as the measured first mapping curve as the optimal solution of the candidate second mapping curve, thereby obtaining the second mapping curve with the minimum objective function, which is used as the second mapping curve corresponding to the first mapping curve, and thus obtaining the actual phase shift.

[0115] In some embodiments, such as Figure 5As shown, the objective function can be a single-valley function with only one minimum value. The Nelder-Mead algorithm can accurately search for the phase shift, achieving better results with only a small number of iterations; where F... obj This represents the objective function of the search.

[0116] In some embodiments of this specification, the processor can utilize a search algorithm to find the second mapping curve corresponding to the first mapping curve, thereby obtaining the actual phase shift. In this way, the optimal solution can be found more efficiently, reducing computational complexity and yielding a more accurate second mapping curve.

[0117] S5: Using the first and second mapping curves, the corresponding phase shift is obtained through calculation.

[0118] Phase shift is a parameter that reflects the magnitude of the phase shift between two frames of fringes.

[0119] In some embodiments, the processor can determine the corresponding phase shift based on a formula:

[0120]

[0121]

[0122] Where (δ1,δ2) m Let F represent the phase shift obtained in the m-th search, where δ1 represents the first phase shift, δ2 represents the second phase shift, and F represents the second phase shift. obj This represents the objective function to be searched.

[0123] S6: Determine whether the phase shift satisfies the iteration condition. If not, return to S1; if yes, use the phase shift as the phase shift result to determine the corrected phase distribution.

[0124] The iteration condition can be that the difference in phase shift between two iterations is less than 0.001 rad, etc.

[0125] In some embodiments, the processor can compare the phase shift of the current iteration with that of the previous iteration to determine whether the phase shift satisfies the iteration condition. If it does not satisfy the condition, it returns to S1 for the next iteration. If it does satisfy the condition, the processor uses the phase shift of the current iteration as the phase shift result and calculates the corrected phase distribution.

[0126] The corrected phase distribution is the phase distribution image after error correction.

[0127] In some embodiments, the processor can use the phase shift result to determine I after the k-th iteration. n The cosine and sine values ​​of the C major scale are calculated to determine the corrected phase distribution.

[0128] In some embodiments, the processor can use a phase shift error self-correction method based on active phase difference mapping to correct the phase shift error of the three-dimensional measurement system, thereby recovering high-precision three-dimensional information of the object surface.

[0129] In some embodiments, the processor can use a phase shift error self-correction method based on active phase difference mapping to correct the phase shift error of the interferometric measurement system, thereby obtaining high-precision measurement results.

[0130] In some embodiments of this specification, the processor can utilize iterative algorithms and active phase difference mapping algorithms to achieve phase shift error self-correction, thereby obtaining the corrected phase distribution. In this way, the influence of object height distribution and incomplete periodic phase distribution on correction accuracy can be eliminated, achieving high-precision phase shift error self-correction even under measurement conditions using low-density fringes. This method is applicable to various fringe types, providing a more universal solution to phase shift error problems in the field of optical technology.

[0131] Example 3

[0132] In some embodiments, the processor can utilize a phase shift error self-correction method based on active phase difference mapping to recover the three-dimensional information of an object surface, including: S1: Based on the phase shift fringes modulated by the object height, an iterative algorithm is used to obtain the iterative background light intensity and modulation degree; S2: Based on the iterative background light intensity and modulation degree, the adjusted phase shift fringe intensity is determined by adjustment; S3: Based on the adjusted phase shift fringe intensity, an active phase difference mapping algorithm is used to obtain a first mapping curve; S4: Based on the first mapping curve, a second mapping curve is obtained through simulation; S5: Using the first mapping curve and the second mapping curve, the corresponding phase shift amount is calculated; S6: It is determined whether the phase shift amount meets the iteration condition. If not, the process returns to S1; if so, the phase shift amount is used as the phase shift amount result to determine the corrected phase distribution and recover high-precision three-dimensional information of the object surface.

[0133] In some embodiments, the iterative expressions for background light intensity and modulation degree are specifically as follows:

[0134]

[0135] in,[·] -1 This represents finding the inverse of a matrix, A. k Indicates the result after the k-th iteration Background light intensity, Indicates the result after the k-th iteration The cosine value of the modulation system, Indicates the result after the k-th iteration The sine value of the modulation system, This represents the cosine value of the first phase shift in the (k-1)th iteration. This represents the sine value of the first phase shift in the (k-1)th iteration. This represents the cosine value of the second phase shift in the (k-1)th iteration. This represents the sine value of the second phase shift in the (k-1)th iteration. This indicates the intensity of the phase shift fringes in the first frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the second frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the third frame actually captured by the camera.

[0136] In some embodiments, the adjusted expression for the phase-shifted fringe intensity is specifically as follows:

[0137]

[0138] in, Indicates according to and The adjusted stripes in frame n+1. This represents the stripe in the (n+1)th frame actually captured by the camera. This represents the average background light intensity. This represents the mean of the adjustment system. Represents phase information, δ n This represents the phase shift of the stripes in the (n+1)th frame.

[0139] In some embodiments, the processor may implement S3 based on the following steps: S310: Based on the adjusted phase shift fringe intensity, determine the original phase distribution and the phase distribution after active phase shift using a formula; S320: Determine the active phase difference by calculating the difference between the active phase shift phase distribution and the original phase distribution; S330: Based on the active phase shift phase distribution and the active phase difference, obtain the first mapping curve using an active phase difference mapping algorithm.

[0140] In some embodiments, the expression for the first mapping curve is specifically:

[0141]

[0142]

[0143]

[0144]

[0145] Where G1 represents the first mapping curve, express and The mapping relationship, Represents the original phase distribution. This represents the phase distribution after active phase shifting. ε represents the active phase difference, and ε represents the active phase shift. This indicates the adjusted stripe intensity of the first frame. This indicates the adjusted stripe intensity for the second frame. P represents the adjusted stripe intensity of the 3rd frame. 11 P 12 P 13 P 14 P 15 P 21 P 22 P 23 P 24 and P 25 Each represents the corresponding active phase difference coefficient.

[0146] In some embodiments, the processor may implement S4 based on the following steps: S410: Based on the first mapping curve, use a search algorithm to simulate an initial second mapping curve; S420: Based on the initial second mapping curve, perform a search and take the curve with the highest similarity to the first mapping curve as the corresponding second mapping curve.

[0147] In some embodiments, the phase shift expression is specifically as follows:

[0148]

[0149]

[0150] Where (δ1,δ2) m Let F represent the phase shift obtained in the m-th search, where δ1 represents the first phase shift, δ2 represents the second phase shift, and F represents the second phase shift. obj Let G1 represent the search objective function, G2 represent the first mapping curve, and G2 represent the second mapping curve.

[0151] In some embodiments, the processor can utilize a phase shift error self-correction system based on active phase difference mapping to reconstruct high-precision three-dimensional information of an object surface, including an acquisition module, a determination module, a first mapping module, a second mapping module, an analysis module, and a judgment module: The acquisition module is used to obtain the iterative background light intensity and modulation degree based on the phase shift fringes modulated by the object height using an iterative algorithm; The determination module is used to determine the adjusted phase shift fringe intensity based on the iterative background light intensity and modulation degree by adjustment; The first mapping module is used to obtain a first mapping curve based on the adjusted phase shift fringe intensity using an active phase difference mapping algorithm; The second mapping module is used to obtain a second mapping curve based on the first mapping curve by simulation; The analysis module is used to calculate the corresponding phase shift amount using the first mapping curve and the second mapping curve; The judgment module is used to determine whether the phase shift amount meets the iteration condition. If not, it returns to the acquisition module; if so, it uses the phase shift amount as the phase shift amount result to determine the corrected phase distribution and recover the high-precision three-dimensional information of the object surface.

Claims

1. A phase shift error self-correction method based on active phase difference mapping, characterized in that, include: S1: Based on phase-shifting fringes, the background light intensity and modulation index are obtained using an iterative algorithm; S2: Based on the background light intensity and modulation degree after the iteration, the intensity of the adjusted phase-shifted fringes is determined by adjustment; S3: Based on the adjusted phase-shift fringe intensity, a first mapping curve is obtained using an active phase difference mapping algorithm; S3 includes: S310: Based on the adjusted phase shift fringe intensity, determine the original phase distribution and the phase distribution after active phase shift; S320: Determine the active phase difference by calculating the difference between the phase distribution after active phase shift and the original phase distribution; S330: Based on the phase distribution after active phase shift and the active phase difference, the first mapping curve is obtained using the active phase difference mapping algorithm; The first mapping curve expression is as follows: ； ； ； ； in, This represents the first mapping curve. express and The mapping relationship, Represents the original phase distribution. This represents the phase distribution after active phase shifting. Indicates active phase difference, Indicates the active phase shift quantity. This indicates the adjusted stripe intensity of the first frame. This indicates the adjusted stripe intensity of the second frame. This indicates the adjusted stripe intensity of the 3rd frame. , , , , , , , , and Each represents the corresponding active phase difference coefficient; S4: Based on the first mapping curve, a second mapping curve is obtained through simulation; S4 includes: S410: Construct the initial second mapping curve; S420: Based on the initial second mapping curve, perform a search and take the curve with the highest similarity to the first mapping curve as the corresponding second mapping curve; S5: Using the first and second mapping curves, the corresponding phase shift is obtained through calculation; S6: Determine whether the corresponding phase shift satisfies the iteration condition. If not, return to S1; if yes, use the corresponding phase shift as the phase shift result to determine the corrected phase distribution.

2. The phase shift error self-correction method based on active phase difference mapping according to claim 1, characterized in that, The iterative expressions for background light intensity and modulation degree are as follows: ； in, This represents finding the inverse of a matrix. Indicates the first After the second iteration Background light intensity, Indicates the first After the second iteration The cosine value of the modulation system, Indicates the first After the second iteration The sine value of the modulation system, Indicates the first The cosine value of the first phase shift in the next iteration Indicates the first The sine value of the first phase shift in the next iteration Indicates the first The cosine value of the second phase shift in the next iteration Indicates the first The sine value of the second phase shift in the next iteration This indicates the intensity of the phase shift fringes in the first frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the second frame actually captured by the camera. This indicates the intensity of the phase shift fringes in the third frame actually captured by the camera.

3. The phase shift error self-correction method based on active phase difference mapping according to claim 1, characterized in that, The adjusted expression for the phase-shift fringe intensity is as follows: ； in, Indicates according to and The adjusted stripes in frame n+1. This represents the stripe in the (n+1)th frame actually captured by the camera. This represents the average background light intensity. This represents the mean of the adjustment system. Represents phase information, This represents the phase shift of the stripes in the (n+1)th frame.

4. The phase shift error self-correction method based on active phase difference mapping according to claim 1, characterized in that, The specific expression for the phase shift is as follows: ； ； in, Indicates the first The phase shift obtained from the second search Indicates the first phase shift. Indicates the second phase shift. Indicates the search objective function. This represents the first mapping curve. This represents the second mapping curve.

5. A phase shift error self-correction system based on active phase difference mapping for executing the phase shift error self-correction method based on active phase difference mapping according to any one of claims 1 to 4, characterized in that, It includes an acquisition module, a determination module, a first mapping module, a second mapping module, an analysis module, and a judgment module: The acquisition module is used to obtain the background light intensity and modulation degree after iteration based on the phase-shifting fringes using an iterative algorithm; The determining module is used to determine the adjusted phase-shift fringe intensity based on the iterated background light intensity and modulation degree. The first mapping module is used to obtain a first mapping curve based on the adjusted phase shift fringe intensity using an active phase difference mapping algorithm; The second mapping module is used to obtain a second mapping curve through simulation based on the first mapping curve; The analysis module is used to calculate the corresponding phase shift using the first and second mapping curves. The judgment module is used to determine whether the corresponding phase shift quantity satisfies the iteration condition; if not, it returns to the acquisition module. If so, the corresponding phase shift is used as the phase shift result to determine the corrected phase distribution.

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