Polarization correction method and system for linear structured light sensor based on reflected polarized light

Abstract

The invention relates to a linear structured light sensor polarization correction method and system based on reflected polarized light, and the method comprises the steps: obtaining the reflected light intensity of the surface of an object at different polarization angles, calculating a Stokes vector according to the reflected light intensity, building a mapping relation between the reflected light intensity and an incident angle based on the Fresnel law, and correcting the polarization of the linear structured light sensor. Obtaining a light intensity maximum value and a light intensity minimum value; calculating a linear polarization degree based on the maximum light intensity value and the minimum light intensity value, and obtaining an optimal laser incident angle based on the linear polarization degree and the refractive index of the object; constructing a polarization optimization model of a polarization angle and an incident angle by using a Stokes vector, and solving an optimal polarization angle; and acquiring a light stripe image of the polaroid at the optimal polarization angle, and performing polarization correction on the light stripe image based on a Stokes vector to realize three-dimensional measurement of an object. According to the invention, errors caused by factors such as light intensity, incident angle and image quality are effectively reduced, and the measurement precision is greatly improved.

Description

Technical Field

[0001] The present disclosure relates to the field of computer vision technology, and in particular to a polarization correction method and system for a linear structured light sensor based on reflected polarized light. Background Art

[0002] Due to their non-contact and simple structure, line structured light sensors (L-LVS) are widely used in reverse engineering, shape measurement, industrial inspection, identification, and positioning. A line structured light sensor primarily consists of a line-structured laser source and a camera. The line-structured laser source projects a light plane that intersects the object's surface, forming a light stripe. The camera captures an image of the light stripe. Calibration can be used to derive the light plane equation in the camera coordinate system. This allows the three-dimensional (3D) coordinates of the object's surface to be calculated from the pixel coordinates corresponding to the center of the light stripe.

[0003] Researchers have proposed numerous light plane calibration methods. Based on target classification, these methods can be categorized as those based on one-dimensional, two-dimensional, and three-dimensional targets. Based on principle, they can be categorized as those based on Plücker lines, homogeneity constraints, and vanishing lines. While these methods can achieve light plane calibration, measurement errors still exist in the sensor after calibration. Measurement errors are composed of errors inherent in the calibration process and errors introduced during the measurement process. Regarding measurement errors, one study analyzed measurement errors and light plane calibration errors in line structured light measurement systems based on Taylor expansion and matrix perturbation principles, establishing an error propagation model. However, this model only addresses the cross-ratio invariance principle, resulting in significant limitations and computational cost. Another study established an error model for line structured light measurement systems for pipeline inner wall inspection applications, but this model is only applicable to this scenario and lacks universal applicability. Another study has implemented metrological evaluation of line structured light scanning systems using standard measuring tools, but this method is inefficient and time-consuming. While these methods can assess the systematic errors of line structured light scanning systems, most existing methods focus solely on a single source of systematic error in line structured light sensors and propose corresponding solutions, failing to integrate all major error sources in the system. This decentralized approach lacks systematicity and comprehensiveness, making it difficult to form a complete error assessment and measurement system. Consequently, its versatility and practicality in practical applications are limited, and it cannot significantly improve measurement accuracy. Summary of the Invention

[0004] In order to solve the problems that the existing methods are limited in versatility and practicality in practical applications and have low measurement accuracy, the present disclosure proposes a polarization correction method for a linear structured light sensor based on reflected polarized light to solve the above problems.

[0005] According to one aspect of the present disclosure, a polarization correction method for a linear structured light sensor based on reflected polarized light is provided, comprising: S10, obtaining the reflected light intensity at different polarization angles on the object surface, calculating the Stokes vector based on the reflected light intensity, establishing a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtaining the maximum and minimum light intensity values; S20, calculating the linear polarization degree based on the maximum light intensity and the minimum light intensity, and obtaining the optimal laser incident angle based on the linear polarization degree and the refractive index of the object; wherein the optimal laser incident angle is calculated by the following formula: , Where n is the refractive index of the object, θ is the optimal laser incident angle, DOLP is the degree of linear polarization, where , and are the maximum and minimum light intensity values, respectively; S30, based on the optimal laser incident angle, using the Stokes vector to construct a polarization optimization model of the polarization angle and the incident angle, and solve the optimal polarization angle; S40 , obtaining a light fringe image of the polarizer at the optimal polarization angle, and performing polarization correction on the light fringe image based on the Stokes vector to achieve three-dimensional measurement of the object.

[0006] Preferably, the Stokes vector is calculated according to the reflected light intensity, which is expressed as: , in, represents the total light intensity, represents the variance of the horizontally polarized light intensity relative to the vertically polarized light intensity, represents the variance of the intensity of light with 45° polarization relative to that with 135° polarization, represents the change in light intensity of the right-hand circularly polarized flux relative to the left-hand circularly polarized flux, 、 are the horizontal and vertical components of the amplitude of the light vector, is the phase of the light vector.

[0007] Preferably, a mapping relationship between reflected light intensity and incident angle is established based on Fresnel's law, which is expressed as: , , in, and are the components of incident light and reflected light parallel to the incident plane, and are the components of incident light and reflected light perpendicular to the incident surface, is the reflection coefficient of the parallel component, is the reflection coefficient of the vertical component, is the angle of incidence, is the refraction angle, is the refractive index of the medium before incident on the incident surface, is the refractive index of the medium after incident on the incident surface.

[0008] Preferably, a mapping relationship between reflected light intensity and incident angle is established based on Fresnel's law to obtain the maximum and minimum light intensity values, including: The light transmission direction is adjusted by rotating the polarizer in front of the camera. When the light transmission direction of the polarizer is consistent with the polarization direction of the reflected light, the detected reflected light intensity reaches the maximum light intensity, which is the component of the reflected light perpendicular to the incident surface. When the transmission direction of the polarizer is perpendicular to the polarization direction of the reflected light, the detected reflected light intensity reaches the minimum value, which is the component of the reflected light parallel to the incident plane. .

[0009] Preferably, a polarization optimization model of polarization angle and incident angle is constructed using the Stokes vector to solve the optimal polarization angle, which is expressed as: , , Where, is the optimal polarization angle, is the intensity of the outgoing light, and α is the polarization angle.

[0010] Preferably, performing polarization correction on the light streak image based on the Stokes vector comprises: Extract the polarization phase distribution of the light streak image and calculate the phase angle based on the Stokes vector; Applying a pre-calibrated phase angle-pixel offset mapping table to perform geometric correction on the light streak image; The polarization-weighted grayscale centroid method is used to locate the sub-pixel center of the corrected light streak image.

[0011] According to one aspect of the present disclosure, a polarization correction system for a linear structured light sensor based on reflected polarized light is provided, comprising: A mapping relationship establishment module obtains the reflected light intensity of the object surface at different polarization angles, calculates the Stokes vector based on the reflected light intensity, establishes a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtains the maximum and minimum light intensity; The optimal laser incident angle calculation module calculates the linear polarization degree based on the maximum light intensity and the minimum light intensity, and obtains the optimal laser incident angle based on the linear polarization degree and the refractive index of the object; wherein the optimal laser incident angle is calculated by the following formula: , Where n is the refractive index of the object, θ is the optimal laser incident angle, DOLP is the degree of linear polarization, where , and are the maximum and minimum light intensity values, respectively; The optimal polarization angle calculation module uses the Stokes vector to construct a polarization optimization model of polarization angle and incident angle based on the optimal laser incident angle to solve the optimal polarization angle; The three-dimensional measurement module obtains a light stripe image of the polarizer at the optimal polarization angle, performs polarization correction on the light stripe image based on the Stokes vector, and realizes three-dimensional measurement of the object.

[0012] According to one aspect of the present disclosure, an electronic device is provided, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to: execute the above-mentioned polarization correction method for a line structured light sensor based on reflected polarized light.

[0013] According to one aspect of the present disclosure, a computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the polarization correction method of the linear structured light sensor based on reflected polarized light is implemented.

[0014] Compared with the prior art, the beneficial effects of the present disclosure are: 1) This paper analyzes the relationship between light intensity and incident angle through the polarization characteristics of light reflected from the surface of an object, establishes a model for solving the optimal polarization angle of a polarizer using the Stokes vector, and studies the relationship between the polarization angle and the incident angle, thereby improving the image quality of highly reflective objects and reducing calibration errors.

[0015] 2) The present disclosure uses a polarization differential imaging model to remove scattered light, effectively solving the influence of ambient light, effectively improving the image quality of the measured object, reducing measurement errors, and improving measurement accuracy.

[0016] 3) This disclosure constructs a complete polarization angle → incident angle → image processing error control chain. It does not simply use the Stokes vector to calculate the optimal polarization angle of the polarizer. This system integration has never appeared in previous existing technologies. It can reduce errors by integrating the minimum light intensity strategy, incident angle optimization and differential imaging.

[0017] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0018] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and, together with the specification, are used to explain the technical solutions of the present disclosure.

[0020] Figure 1 A flow chart of a polarization correction method for a linear structured light sensor based on reflected polarized light is shown; Figure 2 A real-life diagram of a highly reflective object measured in an embodiment of the present disclosure is shown; Figure 3 A schematic diagram of a polarization correction system for a linear structured light sensor based on reflected polarized light in an example of the present disclosure is shown. DETAILED DESCRIPTION

[0021] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0022] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0023] The term "and / or" herein simply describes an association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent the existence of three situations: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" herein refers to any combination of at least two of any one or more of a plurality of items. For example, "at least one of A, B, and C" can represent any one or more elements selected from the set consisting of A, B, and C.

[0024] In addition, numerous specific details are provided in the following detailed description to better illustrate the present disclosure. Those skilled in the art will appreciate that the present disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main points of the present disclosure.

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Example 1 Based on the above ideas, the present invention proposes a polarization correction method for a linear structured light sensor based on reflected polarized light. Figure 1 A flow chart showing a method for polarization correction of a linear structured light sensor based on reflected polarized light is provided. The method includes: S10, obtaining the reflected light intensity at different polarization angles on the object surface, calculating the Stokes vector based on the reflected light intensity, establishing a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtaining the maximum and minimum light intensity values; S20, calculating the linear polarization degree based on the maximum light intensity and the minimum light intensity, and obtaining the optimal laser incident angle based on the linear polarization degree and the refractive index of the object; wherein the optimal laser incident angle is calculated by the following formula: , Where n is the refractive index of the object, θ is the optimal laser incident angle, DOLP is the degree of linear polarization, where , and are the maximum and minimum light intensity values, respectively; S30, based on the optimal laser incident angle, using the Stokes vector to construct a polarization optimization model of the polarization angle and the incident angle, and solve the optimal polarization angle; S40 , obtaining a light fringe image of the polarizer at the optimal polarization angle, and performing polarization correction on the light fringe image based on the Stokes vector to achieve three-dimensional measurement of the object.

[0027] The disclosed embodiments construct a complete error control chain: optimal laser incident angle → optimal polarization angle → polarization correction of the light streak image based on the Stokes vector. Rather than simply using the Stokes vector to determine the optimal polarization angle for the polarizer, errors can be reduced by integrating a minimum light intensity strategy, incident angle optimization, and differential imaging. The specific steps of the polarization correction method for a linear structured light sensor based on reflected polarized light are as follows: S10. Obtain the reflected light intensity of the object surface at different polarization angles, calculate the Stokes vector according to the reflected light intensity, establish a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtain the maximum and minimum light intensity.

[0028] In this embodiment, the polarization state of light can be expressed by the Stokes parameter , according to the amplitude component of the light vector in the reflected light intensity 、 and phase The relationship between the Stokes vector and the Stokes vector is: , in, represents the total light intensity, represents the variance of the horizontally polarized light intensity relative to the vertically polarized light intensity, represents the variance of the intensity of light with 45° polarization relative to that with 135° polarization, represents the change in light intensity of the right-hand circularly polarized flux relative to the left-hand circularly polarized flux, 、 are the horizontal and vertical components of the amplitude of the light vector, is the phase of the light vector.

[0029] The intensity of light reflected from the surface of an object can be divided into two parts: specular reflection intensity and diffuse reflection intensity. When a laser is irradiated onto the surface of an object, a portion of the light is directly reflected on the surface of the object. This portion of reflected light is called specular reflection intensity. The other portion of light is transmitted into the interior of the object and is scattered into the incident space after multiple reflections inside. This portion of light is called diffuse reflection intensity. For highly reflective and smooth objects, the intensity of light reflected from the surface of the object is basically only specular reflection intensity, and the diffuse reflection intensity can be ignored. According to the electromagnetic theory of light, the relationship between the incident light intensity, the amplitude of the reflected light intensity, and the phase can be obtained. Based on the Fresnel law, the mapping relationship between the reflected light intensity and the incident angle is established, which is expressed as: , , in, and are the components of incident light and reflected light parallel to the incident plane, and are the components of incident light and reflected light perpendicular to the incident surface, is the reflection coefficient of the parallel component, is the reflection coefficient of the vertical component, is the angle of incidence, is the refraction angle, is the refractive index of the medium before incident on the incident surface, is the refractive index of the medium after incident on the incident surface.

[0030] In some embodiments, a mapping relationship between reflected light intensity and incident angle is established based on Fresnel's law to obtain maximum and minimum light intensity values, including: Among them, the light transmission direction can be adjusted by rotating the polarizer in front of the camera. When the light transmission direction of the polarizer is consistent with the polarization direction of the reflected light, the detected reflected light intensity reaches the maximum value. When the light transmission direction of the polarizer is perpendicular to the polarization direction of the reflected light, the detected reflected light intensity reaches the minimum value.

[0031] The light transmission direction is adjusted by rotating the polarizer in front of the camera. When the light transmission direction of the polarizer is consistent with the polarization direction of the reflected light, the detected reflected light intensity reaches the maximum light intensity. , the maximum light intensity is the component of the reflected light perpendicular to the incident surface When the transmission direction of the polarizer is perpendicular to the polarization direction of the reflected light, the detected reflected light intensity reaches the minimum value. , the minimum light intensity is the component of the reflected light parallel to the incident surface .

[0032] S20, based on the maximum light intensity and minimum light intensity Calculate the linear polarization degree DOLP , based on the linear polarization degree DOLP and the object refractive index n to obtain the optimal laser incident angle θ.

[0033] In this embodiment, a polarizing filter is placed in front of the camera, and the brightness changes as the filter is rotated. Assuming the plane of incidence is 45°, the reflected light intensity is maximum when perpendicular to the plane of incidence, and minimum when parallel to the plane of incidence. This produces a sinusoidal waveform with maximum and minimum light intensity values: the maximum and minimum light intensity detected during one rotation of the polarizing filter. When the polarizing filter aligns with the polarization angle, the reflected light intensity is maximum. When the polarizing filter aligns with the polarization angle, the reflected light intensity is minimum.

[0034] By recording the change in reflected light intensity during one rotation of the polarizer, fitting a sinusoidal waveform, and extracting the maximum and minimum values ​​of the reflected light intensity, the linear polarization degree is calculated. DOLP , and according to the linear polarization degree DOLP The optimal polarization angle is determined as a function of the incident angle, wherein the linear polarization degree DOLP Expressed as: , Where n is the refractive index of the object, the linear polarization degree DOLP That is, it is a function of n and θ. Conversely, if the linear polarization degree is known, DOLP and the object's refractive index n, the optimal laser incident angle θ can also be calculated.

[0035] Among them, the linear polarization degree DOLP It can also be expressed as: , and are the maximum and minimum light intensity values, respectively; When the optimal polarization angle is obtained, the highlights on the object surface are eliminated to the greatest extent possible, while the camera can also obtain image information to the greatest extent possible, greatly reducing errors caused by image quality issues.

[0036] S30: Based on the optimal laser incident angle, a polarization optimization model of the polarization angle and the incident angle is constructed using the Stokes vector to solve the optimal polarization angle.

[0037] Adjust the incident angle of the laser to the optimal laser incident angle, and then use the Stokes vector to construct a polarization optimization model of the polarization angle and the incident angle; 、 、 Indicates light 、 and The light intensity at three different angles can be ignored because the circular polarization component in the light is very small. = 0, the Stokes vector can be further expressed as: , The Mueller matrix M can also be used to describe the effect of a polarizer. When the polarization angle α changes, the Mueller matrix also changes accordingly. The polarization angle α is the angle of the polarizer.

[0038] , The Mueller matrix M in the formula can also be used to describe the matrix of the polarizer effect. When the polarization angle α changes, the Mueller matrix will also change accordingly.

[0039] Calculate the outgoing light intensity , solving the optimal polarization angle can be expressed as: , , Where, is the optimal polarization angle, is the intensity of the outgoing light, and α is the polarization angle.

[0040] S40 , obtaining a light fringe image of the polarizer at the optimal polarization angle, and performing polarization correction on the light fringe image based on the Stokes vector to achieve three-dimensional measurement of the object.

[0041] Polarization correction is performed on the light streak image based on the Stokes vector, including: extracting the polarization phase distribution of the light streak image and calculating the phase angle according to the Stokes vector; applying a pre-calibrated phase angle-pixel offset mapping table to perform geometric correction on the light streak image; and locating the sub-pixel center of the corrected light streak image using a polarization-weighted grayscale centroid method.

[0042] In this embodiment, multiple light streak images with different polarization directions are acquired by rotating the polarizer, and the polarization state of each pixel is calculated using the Stokes vector. The polarization phase angle is further calculated using the Stokes vector. The light streak image is geometrically corrected by combining the polarization phase angle with a pre-calibrated phase angle-pixel offset mapping table. The sub-pixel center of the corrected light streak image is located using a grayscale centroid method weighted by the degree of linear polarization (DOLP). The coordinates of the corrected light streak center are combined with pre-calibrated camera parameters and the light plane equation to calculate the three-dimensional coordinates of the object surface using the principle of triangulation.

[0043] Specifically, the polarization phase angle is established through experimental calibration α Pixel offset 、 The mapping relationship is used to correct image distortion caused by polarized light reflection.

[0044] The correction formula is: , in, is the original image coordinate, is the corrected coordinate, α is the polarization phase angle.

[0045] By analyzing the polarization phase distribution using Stokes vectors, we address the image distortion caused by polarization characteristics on highly reflective surfaces. Combining a phase angle-pixel offset mapping table with a DOLP weighting algorithm significantly improves the sub-pixel accuracy of light streak centering.

[0046] In order to verify the effectiveness of the method in this embodiment. The experimental system is mainly composed of a Daheng camera (resolution 1920×1200 pixels), a polarizer and a laser (wavelength 650mm), and the camera measurement distance is approximately 1100mm. The measured objects are metal cylinders and metal blocks with relatively smooth surfaces to ensure strong stability of polarized light. The distance from the laser-camera to the object is set to less than 1000mm to ensure the accuracy of the results. A polarizer is added in front of the laser and the polarization angle is adjusted to 0° to ensure that the laser emitted from the laser is completely horizontally polarized light and maintains its original polarization state after reflection. In this embodiment, the characteristics of reflected polarized light and optimal polarization differential imaging are studied, focusing on using the characteristics of polarized light to optimize the performance of line structured light sensors, analyze errors and reduce errors. The focal length of the lens installed on the camera is set to 16mm, the aperture of the camera is f / 8 (where f represents the aperture number, and f / 8 means the aperture number is 8 in this field), and the exposure time is set to 2000ms.

[0047] The method in this embodiment is compared with the method in the literature (Zhu Z, Liu H, Zhang JZ Y. Calibration method of line-structured light sensors based on a hinge-connected target with arbitrary pinch angles [J]. Applied optics, 2023, 62(7): 1695-1703. DOI:10.1364 / ao. 483595.) to measure a 70 mm high metal block and a 150 mm high metal cylinder. The laser is projected onto the measured object, generating four feature points D1, D2, D3, and D4, as shown in Figure 2. Figure 2 Therefore, the measured height of the metal gauge block is: , The measured height of the metal cylinder is: , The measurement error value (∆d) is calculated based on the actual value of the workpiece. The measured values ​​of the part dimensions are shown in the following table:

[0048]

[0049] The table shows that, compared to the methods in the literature, the root mean square error (RMSE) of the method in this embodiment is reduced to 0.0353 mm and 0.0458 mm, respectively, for the measurement of metal blocks and cylinders. This demonstrates lower measurement error and higher precision. Furthermore, the method in this embodiment excels in reducing ambient light interference and improving image quality, effectively reducing errors during the calibration process and enhancing the reliability of the measurement results.

[0050] The above experiments demonstrate the effectiveness of the method proposed in this embodiment for high-precision measurement. Through precise linear structured light localization and polarization differential imaging, the accuracy and reliability of measurements are significantly improved. The experimental results demonstrate that this method not only improves measurement accuracy but also enhances system robustness.

[0051] The disclosed embodiment proposes a polarization correction method for a line structured light sensor based on reflected polarized light. This method analyzes the relationship between light intensity and incident angle through the polarization characteristics of light reflected from the surface of an object. The Stokes vector is further used to establish a solution model for the optimal polarization angle of a polarizer, and the relationship between the polarization angle and the incident angle is studied. The optimal laser incident angle is calculated at the optimal polarization angle. The light stripe image is collected, the light plane is calibrated, and three-dimensional measurements of highly reflective objects are performed based on the calibration results. This method systematically integrates the influencing factors of the main error sources of line structured light sensors, allowing them to influence each other, forming a complete error evaluation and measurement system. It effectively reduces errors caused by physical factors such as light intensity, incident angle and image quality, thereby greatly improving measurement accuracy.

[0052] Example 2 As another aspect of the embodiment of the present disclosure, a polarization correction system 100 for a linear structured light sensor based on reflected polarized light is also provided. Figure 3 Shown, including: Mapping relationship establishment module 1 obtains the reflected light intensity of the object surface at different polarization angles, calculates the Stokes vector based on the reflected light intensity, establishes a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtains the maximum and minimum light intensity; The optimal laser incident angle calculation module 2 calculates the linear polarization degree based on the maximum light intensity and the minimum light intensity, and obtains the optimal laser incident angle based on the linear polarization degree and the refractive index of the object; wherein the optimal laser incident angle is calculated by the following formula: , Where n is the refractive index of the object, θ is the optimal laser incident angle, DOLP is the degree of linear polarization, where , and are the maximum and minimum light intensity values, respectively; The optimal polarization angle calculation module 3 constructs a polarization optimization model of the polarization angle and the incident angle based on the optimal laser incident angle using the Stokes vector to solve the optimal polarization angle; The three-dimensional measurement module 4 obtains a light fringe image of the polarizer at the optimal polarization angle, performs polarization correction on the light fringe image based on the Stokes vector, and realizes three-dimensional measurement of the object.

[0053] In the absence of any contradiction, the above modules in the system of the embodiment of the present disclosure can implement any implementation of the above method.

[0054] Based on the description of the above embodiments, it can be seen that the embodiments of the present disclosure can achieve the following technical effects: 1) The disclosed embodiments analyze the relationship between light intensity and incident angle through the polarization characteristics of light reflected from an object's surface, establish a model for solving the optimal polarization angle of a polarizer using the Stokes vector, and study the relationship between the polarization angle and the incident angle, thereby improving the image quality of highly reflective objects and reducing calibration errors.

[0055] 2) The optimal polarization angle calculation module used in the embodiments of the present disclosure removes scattered light, effectively solves the influence of ambient light, effectively improves the image quality of the measured object, reduces measurement errors, and improves measurement accuracy.

[0056] The present disclosure also provides an electronic device comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to implement the aforementioned polarization correction method for a linear structured light sensor based on reflected polarized light. The electronic device can be provided as a terminal, server, or other device.

[0057] The present disclosure also provides a computer-readable storage medium having computer program instructions stored thereon. When executed by a processor, the computer program instructions implement the aforementioned polarization correction method for a linear structured light sensor based on reflected polarized light. The computer-readable storage medium may be a non-volatile computer-readable storage medium.

[0058] Those skilled in the art will understand that in the specific implementation of the above-mentioned method and system for polarization correction of linear structured light sensors based on reflected polarized light, the writing order of the steps does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0059] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and the part of the module, program segment or instruction contains one or more executable instructions for realizing the prescribed logical function. In some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the prescribed function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0060] While various embodiments of the present disclosure have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technical improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A polarization correction method for a linear structured light sensor based on reflected polarized light, characterized in that: The steps include: S10, obtaining the reflected light intensity at different polarization angles on the object surface, calculating the Stokes vector based on the reflected light intensity, establishing a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtaining the maximum and minimum light intensity values; S20, calculating the linear polarization degree based on the maximum light intensity and the minimum light intensity, and obtaining the optimal laser incident angle based on the linear polarization degree and the refractive index of the object; wherein the optimal laser incident angle is calculated by the following formula: ， Where n is the refractive index of the object, θ is the optimal laser incident angle, DOLP is the degree of linear polarization, where ， and are the maximum and minimum light intensity values ​​respectively; S30, based on the optimal laser incident angle, using the Stokes vector to construct a polarization optimization model of the polarization angle and the incident angle, and solve the optimal polarization angle; S40 , obtaining a light fringe image of the polarizer at the optimal polarization angle, and performing polarization correction on the light fringe image based on the Stokes vector to achieve three-dimensional measurement of the object.

2. The method according to claim 1, characterized in that The Stokes vector is calculated based on the reflected light intensity and is expressed as: ， in, represents the total light intensity, represents the variance of the horizontally polarized light intensity relative to the vertically polarized light intensity, represents the variance of the intensity of light with 45° polarization relative to that with 135° polarization, represents the change in light intensity of the right-hand circularly polarized flux relative to the left-hand circularly polarized flux, 、 are the horizontal and vertical components of the amplitude of the light vector, is the phase of the light vector.

3. The method according to claim 2, characterized in that The mapping relationship between reflected light intensity and incident angle is established based on Fresnel's law, which is expressed as: ， ， in, and are the components of incident light and reflected light parallel to the incident plane, and are the components of incident light and reflected light perpendicular to the incident surface, is the reflection coefficient of the parallel component, is the reflection coefficient of the vertical component, is the angle of incidence, is the refraction angle, is the refractive index of the medium before incident on the incident surface, is the refractive index of the medium after incident on the incident surface.

4. The method according to claim 3, characterized in that Based on Fresnel's law, the mapping relationship between reflected light intensity and incident angle is established to obtain the maximum and minimum light intensity, including: The light transmission direction is adjusted by rotating the polarizer in front of the camera. When the light transmission direction of the polarizer is consistent with the polarization direction of the reflected light, the detected reflected light intensity reaches the maximum light intensity, which is the component of the reflected light perpendicular to the incident surface. When the transmission direction of the polarizer is perpendicular to the polarization direction of the reflected light, the detected reflected light intensity reaches the minimum value, which is the component of the reflected light parallel to the incident plane. .

5. The method according to claim 4, characterized in that The Stokes vector is used to construct a polarization optimization model of polarization angle and incident angle to solve the optimal polarization angle, which is expressed as: ， ， Where, is the optimal polarization angle, is the intensity of the outgoing light, and α is the polarization angle.

6. The method according to claim 1, characterized in that Performing polarization correction on the light streak image based on the Stokes vector includes: Extract the polarization phase distribution of the light streak image and calculate the phase angle based on the Stokes vector; Applying a pre-calibrated phase angle-pixel offset mapping table to perform geometric correction on the light streak image; The polarization-weighted grayscale centroid method is used to locate the sub-pixel center of the corrected light streak image.

7. A polarization correction system for a linear structured light sensor based on reflected polarized light, characterized in that: include: A mapping relationship establishment module obtains the reflected light intensity of the object surface at different polarization angles, calculates the Stokes vector based on the reflected light intensity, establishes a mapping relationship between the reflected light intensity and the incident angle based on the Fresnel law, and obtains the maximum and minimum light intensity; The optimal laser incident angle calculation module calculates the linear polarization degree based on the maximum light intensity and the minimum light intensity, and obtains the optimal laser incident angle based on the linear polarization degree and the refractive index of the object; wherein the optimal laser incident angle is calculated by the following formula: ， Where n is the refractive index of the object, θ is the optimal laser incident angle, DOLP is the degree of linear polarization, where ， and are the maximum and minimum light intensity values ​​respectively; An optimal polarization angle calculation module, based on the optimal laser incident angle, uses the Stokes vector to construct a polarization optimization model of the polarization angle and the incident angle to solve the optimal polarization angle; The three-dimensional measurement module obtains a light stripe image of the polarizer at the optimal polarization angle, performs polarization correction on the light stripe image based on the Stokes vector, and realizes three-dimensional measurement of the object.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the polarization correction method for a linear structured light sensor based on reflected polarized light according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the polarization correction method for a linear structured light sensor based on reflected polarized light according to any one of claims 1 to 6 is implemented.

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