Multispectral structured light path system

Abstract

The invention relates to the technical field of optical imaging and three-dimensional measurement, in particular to a multispectral structured light path system which comprises a light source module used for generating multi-wavelength light; the collimation system module is composed of any one of one or more lenses, and an aperture diaphragm is arranged on the first face. When the system is used, a multispectral light source design is adopted, the system can meet the three-dimensional measurement requirements of various complex material surfaces, the system adaptability is conveniently and remarkably improved, the image contrast is enhanced through multi-wavelength structured light projection, and the measurement precision is improved. The method effectively reduces the mismatching rate, improves the precision and reliability of three-dimensional reconstruction, achieves the simultaneous obtaining of multispectral information and structured light three-dimensional shape information, expands the application capability of the system in the high-end fields of material recognition, surface defect detection and the like, employs an integrated optical path design, is compact in structure, is high in reliability, and is suitable for large-scale popularization and application. And miniaturization and engineering application of the system are facilitated, and the portability and practicability of the equipment are improved.

Description

Technical Field

[0001] This invention relates to the field of optical imaging and three-dimensional measurement technology, specifically to a multispectral structured light optical path system. Background Technology

[0002] With the continuous development of optical imaging and 3D measurement technologies, structured light technology, due to its non-contact, high precision, and real-time characteristics, has been widely applied in various fields such as industrial inspection, reverse engineering, biometrics, robot vision, and 3D scanning reconstruction. Traditional structured light systems typically use a single-wavelength light source for projection. While this can meet routine measurement needs to a certain extent, it often suffers from insufficient contrast, high mismatch rates, and decreased measurement accuracy when dealing with complex surface materials, ambient lighting interference, or multi-media targets. To address these issues, researchers have recently begun exploring the integrated application of multispectral imaging and structured light technologies.

[0003] The following problems may occur when using existing technologies:

[0004] Existing structured light 3D measurement systems mostly use a single wavelength light source, which is difficult to adapt to the high-precision measurement requirements of complex material surfaces (such as highly reflective, transparent, porous, etc.).

[0005] When faced with ambient light interference, single-wavelength structured light exhibits a significant decrease in image contrast, leading to an increased mismatch rate and affecting the stability and reliability of measurements.

[0006] Existing structured light systems cannot simultaneously acquire the geometric shape and spectral information of a target object, which limits their applicability in high-end applications such as material identification and defect detection.

[0007] In existing multispectral structured light systems, the integration of light sources of different wavelengths is complex, resulting in large optical path structures and poor system stability.

[0008] In existing technologies, the projection pattern control of multispectral structured light is not precise enough, making it difficult to achieve high-precision coded light projection.

[0009] The imperfect synchronization control mechanism of the multispectral structured light system leads to a timing mismatch between light source projection and image acquisition, affecting measurement efficiency and accuracy.

[0010] Existing multispectral structured light systems are costly and have low integration, which makes them unsuitable for large-scale application in industrial settings.

[0011] Existing multispectral structured light optical paths mostly use a single glass substrate coated with multiple optical films to selectively pass one or three types of light. The spectral scalability is very low, and the cost is high. The glass substrate must be replaced and recoated every time a wavelength is switched, making the process very cumbersome.

[0012] In conclusion, developing a multispectral structured light optical path system remains a critical issue that urgently needs to be addressed in the fields of optical imaging and 3D measurement technology. Summary of the Invention

[0013] The purpose of this invention is to address the shortcomings of existing structured light 3D measurement systems, which often employ a single wavelength light source, making it difficult to meet the high-precision measurement requirements of complex material surfaces (such as highly reflective, transparent, and porous surfaces); the significant decrease in image contrast due to ambient light interference, leading to increased mismatch rates and affecting measurement stability and reliability; the inability of existing structured light systems to simultaneously acquire the geometric shape and spectral information of the target object, limiting their applicability in high-end applications such as material identification and defect detection; and the complex integration of different wavelength light sources in existing multispectral structured light systems, resulting in bulky optical path structures and poor system stability. The existing multispectral structured light technology suffers from several drawbacks. First, the projection pattern control is not precise enough, making it difficult to achieve high-precision coded light projection. Second, the imperfect synchronization control mechanism of multispectral structured light systems leads to timing mismatch between light source projection and image acquisition, affecting measurement efficiency and accuracy. Third, existing multispectral structured light systems are costly and have low integration, hindering large-scale application in industrial settings. Fourth, the optical paths of existing multispectral structured light systems often use a single glass substrate coated with multiple optical films, selectively transmitting one or three types of light, resulting in low spectral scalability and high cost. Furthermore, switching wavelengths requires replacing the glass substrate and recoating, making the process extremely cumbersome.

[0014] To achieve the above objectives, the present invention provides a multispectral structured light optical path system, comprising:

[0015] Light source module, used to generate multi-wavelength light;

[0016] The collimation system module is composed of one or more lenses in any way, and the first surface is provided with an aperture stop to collimate the multi-wavelength light into a parallel beam.

[0017] The filter motor module is equipped with a servo motor unit and a filter unit A, which is used to selectively transmit the multi-wavelength light.

[0018] A field stop, positioned at the same location as the aperture stop, is used to block stray light;

[0019] The chrome-plated pattern is positioned at the same physical point in the optical path as the aperture stop, and the arrangement of the chrome-plated pattern can be either periodic or aperiodic.

[0020] Dichroic mirrors / beam splitters are used to combine the light beams of the multi-wavelength light into coaxial light;

[0021] The telecentric lens, employing an object-side telecentric architecture, is used to project the coaxial light onto the target object, thereby suppressing image distortion and achieving balanced illumination distribution across the entire field of view.

[0022] Furthermore, the operation process of the light source module for generating multi-wavelength light includes:

[0023] The light source module employs any one of a monochromatic light source, a halogen lamp, a halogen lamp, or a white LED. When using a white LED, it is paired with a filter module. The filter module is used to form a single-color light source, and the center wavelength of the single-color light source is... ,expression:

[0024]

[0025] In the formula, This indicates the center wavelength of the filtered monochromatic light. , These are the lower and upper limits of the points, respectively. Indicates wavelength variable, Indicates the output light at wavelength The light intensity at that location, Indicates the wavelength range The integral of the product of the internal wavelength and the output light intensity. Indicates the wavelength range The integral of the internal output light intensity, when the light source module uses a white LED paired with a filter module, the filter unit B in the filter module is selected according to the wavelength range determined by the actual measurement requirements.

[0026] Furthermore, the collimation system module, composed of one or more lenses in any manner, and with an aperture stop on its first surface, includes the following operational procedures for collimating the multi-wavelength light rays into a parallel beam:

[0027] Based on the bandwidth and incident angle range of the multi-wavelength light, select from... A lens group consisting of one or more lenses, in any combination of these lenses, must satisfy the Abbe sine condition. For multi-lens combinations, the lens spacing... Must meet:

[0028]

[0029] In the formula, This is the total focal length of the lens group. Let be the focal length of the two lenses, and spherical aberration needs to be corrected using the Seidel aberration formula, expressed as:

[0030]

[0031] In the formula, Indicates the physical quantity The summation operation, It is half the aperture of the lens. Indicates the refractive index of the lens. For aperture position parameters, It represents the fourth power of half the aperture of the lens.

[0032] Furthermore, the operation process of switching the filter motor module, which includes a servo motor unit and filter unit A, for selectively transmitting the multi-wavelength light includes:

[0033] The servo motor unit is communicatively connected to the host computer software. The host computer software sends control commands to the servo motor unit to drive the filter unit A to rotate. The servo motor unit adopts PID position closed-loop control, and the control law expression is as follows:

[0034]

[0035] In the formula, Indicates the servo motor unit at time... Control output quantity, Indicates at time Positional deviation, The proportional coefficient is a parameter of the proportional element in PID control. This indicates that the integral coefficient is a parameter of the integral element in PID control. The derivative coefficients represent the parameters of the derivative element in PID control. Indicates from the initial time At the time Positional deviation The points, It is an integral variable. Indicates positional deviation At any moment rate of change, All PID parameters were tuned using the Ziegler-Nichols method.

[0036] Furthermore, the operation procedure for setting the field stop at the same position as the aperture stop to block stray light includes:

[0037] The field stop and the aperture stop are located at the same position, and the central axis deviation is calibrated at the same position. ,expression:

[0038]

[0039] In the formula, This indicates the deviation between the central axis of the field stop and the aperture stop. For the center coordinate deviation, the blocked stray light includes, but is not limited to, light reflected from the lens surface, internal scattered light, and ambient stray light. The reflectivity of the light reflected from the lens surface satisfies the Fresnel formula, and the scattering intensity of the internal scattered light follows the Mie scattering model, expressed as:

[0040]

[0041] In the formula, Indicates at wavelength of scattering angle is Scattering intensity at that location, The distance from the observation point to the scattering particle. It is the scattering angle. It is the scattering amplitude function. Where is the radius of the scattering particle. The refractive index is given, and the spectral distribution of the ambient stray light conforms to the blackbody radiation model.

[0042] Furthermore, the operation process for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes:

[0043] The chrome-plated pattern and the aperture stop occupy the same physical position in the optical path, and the center positioning accuracy must satisfy the expression:

[0044]

[0045] In the formula, This indicates the positional deviation between the center of the chrome-plated pattern and the center of the aperture stop within the plane. Let be the coordinate dimension of the planar coordinate system. This indicates that the center of the chrome-plated pattern is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the aperture stop is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the chrome-plated pattern is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the aperture stop is in a plane coordinate system. The coordinates of the direction. This means that the positional deviation calculated earlier must be less than or equal to 2 micrometers.

[0046] Furthermore, the operation process for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes:

[0047] The spatial period of the periodic chrome plating pattern satisfy:

[0048]

[0049] In the formula, The spatial period represents the periodicity of the chrome plating pattern. The wavelength of the chrome-plated pattern. It is the angle between the pattern and the axis of the light path. Indicates the included angle Multiplying the sine value by 2, the amplitude transmittance function of the periodic chrome-plated pattern Represented as:

[0050]

[0051] In the formula, It is a periodic chrome plating pattern in spatial coordinates Amplitude transmittance at that location The summation operation represents summing over all integers. arrive The corresponding items are accumulated. Fourier coefficients represent frequency Related constants, Imaginary unit, It is an exponential function. This indicates a spatial frequency correlation with the Fourier series. This indicates the spatial variation of the pattern in the tilt direction.

[0052] Furthermore, the operation process for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes:

[0053] The non-periodic chrome plating pattern is designed using a pseudo-random sequence, and its autocorrelation function is expressed as:

[0054]

[0055] In the formula, The autocorrelation function representing a non-periodic chromium plating pattern. The translation amount, The definite integral symbol represents the interval […]. Perform integration operations on the interval from negative infinity to positive infinity. Represents the integral. These are the lower and upper limits of the points, respectively. Indicates the position of non-periodic chrome plating pattern The amplitude transmittance function at that location. Indicates the position of non-periodic chrome plating pattern The amplitude transmittance function at that location. It is an integral variable The differential, The wavelength of the chrome-plated pattern is determined by any one of the multi-wavelength light emitted by the light source module or the multi-wavelength light filtered by the filter unit A. The chrome-plated pattern is fabricated on the outer surface of the glass substrate using either laser direct writing or electron beam exposure.

[0056] Furthermore, the operation procedure of the dichroic mirror / beam splitter for combining the multi-wavelength light beams into coaxial light includes:

[0057] The multi-wavelength light includes:

[0058]

[0059] In the formula, This represents the first wavelength of light. This represents the second wavelength of light. The ellipsis indicates that there are multiple wavelengths of light in between. Indicates the first The incident direction vectors of the light rays of each wavelength are:

[0060]

[0061] In the formula, Indicates the first The incident direction vector of light rays of each wavelength. The number representing the wavelength , Indicates the first The incident direction vector of each wavelength of light is in Components in the axial direction, Indicates the first The incident direction vector of each wavelength of light is in Components in the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The component along the axial direction, while the incident direction vector satisfies the following condition:

[0062]

[0063] In the formula, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction is used to define the outgoing direction vector of the wavelength ray as follows: Then coaxiality error expression:

[0064]

[0065] In the formula, Indicates the first The coaxiality error of light at each wavelength Represents the inverse cosine function. Represents the ideal coaxial direction vector , Indicates the allowable range of coaxiality error. For the first The actual direction vector of the wavelength light rays after beam combining, the total intensity and intensity fluctuation of the coaxial light, expressed as:

[0066]

[0067] In the formula, This represents the total light intensity after beam combining. The summation symbol represents the summation of terms from the first term to the second term. The quantities of the items are accumulated. Indicates the first The light intensity of each wavelength of light This represents the amount of light intensity fluctuation. It is time The total light intensity of the combined beam at that time, It is the initial moment The total light intensity of the combined beam, The angle and position of the dichroic mirror / beam splitter, which indicate the allowable range of light intensity fluctuations, are dynamically adjusted according to the requirements of the multi-wavelength light beam combining.

[0068] Furthermore, the telecentric lens, employing an object-side telecentric architecture, is used to project the coaxial light onto the target object. The operational process for suppressing image distortion and achieving equal illumination distribution across the entire field of view includes:

[0069] The telecentric lens is mounted at the exit end of the dichroic mirror / beam splitter, and the focal length and position of the telecentric lens are dynamically adjusted according to the measurement distance and field of view requirements to set the field of view angle. With the position of the camera Relational model expression:

[0070]

[0071] In the formula, Indicates the field of view. Indicates half-height field of view. Indicates the camera position. Represents the arctangent function, which requires the field of view to be from Replace with At that time, the amount of adjustment of the camera position expression:

[0072]

[0073] In the formula, Indicates the amount of lens position adjustment. Indicates half-height field of view. Represents the tangent function. Indicates the initial field of view angle. Indicates the target field of view and the camera position. Adjusted resolution expression:

[0074]

[0075] In the formula, Indicates camera position The minimum precision achieved during adjustment. Indicates the field of view. Indicates half-height field of view.

[0076] Beneficial effects

[0077] Compared with known public technologies, the technical solution provided by this invention has the following beneficial effects:

[0078] This invention employs a multispectral light source design, which can adapt to the three-dimensional measurement needs of various complex material surfaces, significantly improving the system's adaptability. Through multi-wavelength structured light projection, image contrast is enhanced, effectively reducing the false matching rate and improving the accuracy and reliability of three-dimensional reconstruction. This invention achieves simultaneous acquisition of multispectral information and structured light three-dimensional morphology information, expanding the system's application capabilities in high-end fields such as material identification and surface defect detection. This invention adopts an integrated optical path design, with a compact structure, facilitating system miniaturization and engineering applications, and improving the portability and practicality of the equipment.

[0079] When in use, this invention supports independent control and synchronous projection of multi-wavelength structured light, improving the flexibility and encoding capability of the projected pattern, which is conducive to achieving high-precision 3D reconstruction. The unified synchronous control mechanism ensures precise timing matching between light source projection and image acquisition, improving measurement efficiency and system stability. The light source module has strong scalability and supports flexible configuration of multiple spectral bands to meet the measurement needs of different application scenarios. It is easy to reduce the overall optical path module size to about 30mm, making the overall cost of this invention low and its integration high, which is conducive to large-scale promotion and application in fields such as industrial inspection, intelligent manufacturing, and robot vision.

[0080] When in use, this invention uses laser direct writing or electron beam exposure to superimpose light of different wavelengths in space onto a glass substrate, avoiding the expensive cost of multiple coatings. At the same time, it expands the spectral width, enabling structured light to achieve non-periodic combinations of different colors, increasing codedness, and significantly improving the accuracy of 3D reconstruction. Attached Figure Description

[0081] Figure 1 This is a system diagram of a multispectral structured optical path system according to the present invention.

[0082] Figure 2 This is a schematic diagram of an imaging system module of a multispectral structured light optical path system according to the present invention.

[0083] Figure 3 This is a schematic diagram of the imaging quality of a multispectral structured light optical path system according to the present invention.

[0084] Figure 4 This is a schematic diagram of the imaging quality of a multispectral structured light optical path system according to the present invention.

[0085] Figure 5 This is a schematic diagram of the illuminance distribution in the chromium-plated area of ​​a multispectral structured light optical path system according to the present invention.

[0086] Figure 6 This is a schematic diagram of a prototype of a multispectral structured light optical path system according to the present invention.

[0087] Figure 7 This is a schematic diagram of the structure of a multispectral structured light optical path system according to the present invention. Detailed Implementation

[0088] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0089] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0090] The present invention will now be described in further detail with reference to the accompanying drawings:

[0091] Example:

[0092] like Figure 1 - Figure 7 As shown, the present invention provides a multispectral structured light optical path system, comprising:

[0093] Light source module, used to generate multi-wavelength light;

[0094] Furthermore, the operation process of the light source module for generating multi-wavelength light includes:

[0095] The light source module employs any one of a monochromatic light source, a halogen lamp, a halogen lamp, or a white LED. When using a white LED, it is paired with a filter module. The filter module is used to form a single-color light source, and the center wavelength of the single-color light source is... ,expression:

[0096]

[0097] In the formula, This indicates the center wavelength of the filtered monochromatic light. , These are the lower and upper limits of the points, respectively. Indicates wavelength variable, Indicates the output light at wavelength The light intensity at that location, Indicates the wavelength range The integral of the product of the internal wavelength and the output light intensity. Indicates the wavelength range The integral of the internal output light intensity, when the light source module uses white LEDs in combination with a filter module, the filter unit B in the filter module is selected according to the wavelength range determined by the actual measurement requirements.

[0098] Specifically, in material composition analysis, based on the characteristic absorption wavelength of the substance to be analyzed, a precise incident light can be obtained through a suitable light source and filter module, thereby accurately detecting the absorption of light of different wavelengths by the substance, improving the accuracy and reliability of the analysis results, and meeting diverse measurement needs.

[0099] The collimation system module is composed of one or more lenses in any way, and the first surface is provided with an aperture stop to collimate the multi-wavelength light into a parallel beam.

[0100] Furthermore, the collimation system module, composed of one or more lenses in any manner, and with an aperture stop on its first surface, includes the following operational procedures for collimating the multi-wavelength light rays into a parallel beam:

[0101] Based on the bandwidth and incident angle range of the multi-wavelength light, select from... A lens group consisting of one or more lenses, in any combination of these lenses, must satisfy the Abbe sine condition. For multi-lens combinations, the lens spacing... Must meet:

[0102]

[0103] In the formula, This is the total focal length of the lens group. Let be the focal length of the two lenses, and spherical aberration needs to be corrected using the Seidel aberration formula, expressed as:

[0104]

[0105] In the formula, Indicates the physical quantity The summation operation, It is half the aperture of the lens. Indicates the refractive index of the lens. For aperture position parameters, It represents the fourth power of half the aperture of the lens.

[0106] Specifically, it efficiently collimates multi-wavelength diverging light into a highly parallel beam, suitable for high-resolution spectral detection or precision imaging. It helps reduce energy loss and measurement errors caused by light divergence. It consists of one or more lenses, with an aperture stop on the incident surface to limit the divergence angle of the incident beam and improve the collimation effect. It uses lens combinations with different focal lengths and must meet the Abbe sine condition to adapt to different wavelengths and incident angle distributions, which helps reduce aberrations and improve the focusing performance and stability of the system.

[0107] The filter motor module is equipped with a servo motor unit and a filter unit A, which is used to selectively transmit the multi-wavelength light.

[0108] Furthermore, the operation process of switching the filter motor module, which includes a servo motor unit and filter unit A, for selectively transmitting the multi-wavelength light includes:

[0109] The servo motor unit is communicatively connected to the host computer software. The host computer software sends control commands to the servo motor unit to drive the filter unit A to rotate. The servo motor unit adopts PID position closed-loop control, and the control law expression is as follows:

[0110]

[0111] In the formula, Indicates the servo motor unit at time... Control output quantity, Indicates at time Positional deviation, The proportional coefficient is a parameter of the proportional element in PID control. This indicates that the integral coefficient is a parameter of the integral element in PID control. The derivative coefficients represent the parameters of the derivative element in PID control. Indicates from the initial time At the time Positional deviation The points, It is an integral variable. Indicates positional deviation At any moment rate of change, All PID parameters were tuned using the Ziegler-Nichols method.

[0112] Specifically, the servo motor unit is connected to the host computer software. The host computer software sends control commands to control the servo motor unit to drive the filter unit A to rotate, which is used to selectively transmit multiple wavelengths of light, thereby improving the stability of imaging quality and the efficiency and accuracy of experimental observation.

[0113] A field stop, positioned at the same location as the aperture stop, is used to block stray light;

[0114] Furthermore, the operation procedure for setting the field stop at the same position as the aperture stop to block stray light includes:

[0115] The field stop and the aperture stop are located at the same position, and the central axis deviation is calibrated at the same position. ,expression:

[0116]

[0117] In the formula, This indicates the deviation between the central axis of the field stop and the aperture stop. For the center coordinate deviation, the blocked stray light includes, but is not limited to, light reflected from the lens surface, internal scattered light, and ambient stray light. The reflectivity of the light reflected from the lens surface satisfies the Fresnel formula, and the scattering intensity of the internal scattered light follows the Mie scattering model, expressed as:

[0118]

[0119] In the formula, Indicates at wavelength of scattering angle is Scattering intensity at that location, The distance from the observation point to the scattering particle. It is the scattering angle. It is the scattering amplitude function. Where is the radius of the scattering particle. The refractive index is given, and the spectral distribution of the ambient stray light conforms to the blackbody radiation model.

[0120] Specifically, by precisely aligning the central axis and shielding various stray light sources, the signal-to-noise ratio of the system's imaging or detection can be improved. By calibrating the central axis deviation of the field stop and aperture stop, the optical centers of the two are kept consistent, which helps to prevent beam skewing from introducing additional errors and improves the sharpness of image edges.

[0121] The chrome-plated pattern is positioned at the same physical point in the optical path as the aperture stop, and the arrangement of the chrome-plated pattern can be either periodic or aperiodic.

[0122] Furthermore, the operation process for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes:

[0123] The chrome-plated pattern and the aperture stop occupy the same physical position in the optical path, and the center positioning accuracy must satisfy the expression:

[0124]

[0125] In the formula, This indicates the positional deviation between the center of the chrome-plated pattern and the center of the aperture stop within the plane. Let be the coordinate dimension of the planar coordinate system. This indicates that the center of the chrome-plated pattern is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the aperture stop is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the chrome-plated pattern is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the aperture stop is in a plane coordinate system. The coordinates of the direction. This means that the positional deviation calculated earlier must be less than or equal to 2 micrometers.

[0126] Furthermore, the operation process for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes:

[0127] The spatial period of the periodic chrome plating pattern satisfy:

[0128]

[0129] In the formula, The spatial period represents the periodicity of the chrome plating pattern. The wavelength of the chrome-plated pattern. It is the angle between the pattern and the axis of the light path. Indicates the included angle Multiplying the sine value by 2, the amplitude transmittance function of the periodic chrome-plated pattern Represented as:

[0130]

[0131] In the formula, It is a periodic chrome plating pattern in spatial coordinates Amplitude transmittance at that location The summation operation represents summing over all integers. arrive The corresponding items are accumulated. Fourier coefficients represent frequency Related constants, Imaginary unit, It is an exponential function. This indicates a spatial frequency correlation with the Fourier series. This indicates the spatial variation of the pattern in the tilt direction.

[0132] Furthermore, the operation process for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes:

[0133] The non-periodic chrome plating pattern is designed using a pseudo-random sequence, and its autocorrelation function is expressed as:

[0134]

[0135] In the formula, The autocorrelation function representing a non-periodic chromium plating pattern. The translation amount, The definite integral symbol represents the interval […]. Perform integration operations on the interval from negative infinity to positive infinity. Represents the integral. These are the lower and upper limits of the points, respectively. Indicates the position of non-periodic chrome plating pattern The amplitude transmittance function at that location. Indicates the position of non-periodic chrome plating pattern The amplitude transmittance function at that location. It is an integral variable The differential, The wavelength of the chrome-plated pattern is determined by any one of the multi-wavelength light emitted by the light source module or the multi-wavelength light filtered by the filter unit A. The chrome-plated pattern is fabricated on the outer surface of the glass substrate using either laser direct writing or electron beam exposure.

[0136] Specifically, the chrome-plated pattern is positioned in the optical path that completely overlaps with the aperture stop, and is arranged in a periodic or non-periodic manner to control the spatial structure of the beam or to achieve specific optical modulation functions. The chrome-plated pattern is manufactured using high-precision processes such as laser direct writing or electron beam exposure. The pattern is formed on the outer surface of the glass substrate to adapt to light sources of different wavelengths or filtered light, which facilitates support for various optical diffraction, imaging and analysis tasks. Periodic patterns can generate stable diffraction arrays, which are suitable for precision optical detection systems such as phase comparison and grating interference.

[0137] Dichroic mirrors / beam splitters are used to combine the light beams of the multi-wavelength light into coaxial light;

[0138] Furthermore, the operation procedure of the dichroic mirror / beam splitter for combining the multi-wavelength light beams into coaxial light includes:

[0139] The multi-wavelength light includes:

[0140]

[0141] In the formula, This represents the first wavelength of light. This represents the second wavelength of light. The ellipsis indicates that there are multiple wavelengths of light in between. Indicates the first The incident direction vectors of the light rays of each wavelength are:

[0142]

[0143] In the formula, Indicates the first The incident direction vector of light rays of each wavelength. The number representing the wavelength , Indicates the first The incident direction vector of each wavelength of light is in Components in the axial direction, Indicates the first The incident direction vector of each wavelength of light is in Components in the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The component along the axial direction, while the incident direction vector satisfies the following condition:

[0144]

[0145] In the formula, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction is used to define the outgoing direction vector of the wavelength ray as follows: Then coaxiality error expression:

[0146]

[0147] In the formula, Indicates the first The coaxiality error of light at each wavelength Represents the inverse cosine function. Represents the ideal coaxial direction vector , Indicates the allowable range of coaxiality error. For the first The actual direction vector of the wavelength light rays after beam combining, the total intensity and intensity fluctuation of the coaxial light, expressed as:

[0148]

[0149] In the formula, This represents the total light intensity after beam combining. The summation symbol represents the summation of terms from the first term to the second term. The quantities of the items are accumulated. Indicates the first The light intensity of each wavelength of light This represents the amount of light intensity fluctuation. It is time The total light intensity of the combined beam at that time, It is the initial moment The total light intensity of the combined beam, The angle and position of the dichroic mirror / beam splitter, which indicate the allowable range of light intensity fluctuations, are dynamically adjusted according to the requirements of the multi-wavelength light beam combining.

[0150] Specifically, the multi-wavelength light beams are combined to form coaxial light, achieving high-precision multi-wavelength light coaxial beam combining. This provides a unified optical path for scenarios such as spectral imaging, multi-channel fluorescence excitation, and interferometric metrology. By dynamically adjusting the angle and position of optical components, it achieves automatic adaptation to different wavelength combinations. By maintaining light intensity stability, it improves the linear response and signal consistency of the back-end detection system. At the same time, it supports the complementary use of beam splitters and dichroic mirrors, adapting to the application requirements of both high precision and wide spectrum.

[0151] The telecentric lens, employing an object-side telecentric architecture, is used to project the coaxial light onto the target object, thereby suppressing image distortion and achieving a balanced illumination distribution across the entire field of view.

[0152] Furthermore, the telecentric lens, employing an object-side telecentric architecture, is used to project the coaxial light onto the target object. The operational process for suppressing image distortion and achieving equal illumination distribution across the entire field of view includes:

[0153] The telecentric lens is mounted at the exit end of the dichroic mirror / beam splitter, and the focal length and position of the telecentric lens are dynamically adjusted according to the measurement distance and field of view requirements to set the field of view angle. With the position of the camera Relational model expression:

[0154]

[0155] In the formula, Indicates the field of view. Indicates half-height field of view. Indicates the camera position. Represents the arctangent function, which requires the field of view to be from Replace with At that time, the amount of adjustment of the camera position expression:

[0156]

[0157] In the formula, Indicates the amount of lens position adjustment. Indicates half-height field of view. Represents the tangent function. Indicates the initial field of view. Indicates the target field of view and the camera position. Adjusted resolution expression:

[0158]

[0159] In the formula, Indicates camera position The minimum precision achieved during adjustment. Indicates the field of view. Indicates half-height field of view.

[0160] Specifically, the telecentric lens is installed at the exit end of the dichroic mirror / beam splitter to uniformly project the combined coaxial light onto the surface of the target object. The object-side telecentric architecture facilitates the elimination of magnification changes and image distortion caused by changes in viewing angle, maintains a constant magnification, and achieves a balanced illumination distribution across the entire field of view, improving brightness consistency and edge detection accuracy. Through a model of the relationship between the fixed field of view and the lens position, it achieves automatic dynamic adjustment to adapt to targets of different sizes or distances.

[0161] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multispectral structured light optical path system, characterized in that, include: Light source module, used to generate multi-wavelength light; The collimation system module is composed of one or more lenses in any way, and the first surface is provided with an aperture stop to collimate the multi-wavelength light into a parallel beam. The filter motor module is equipped with a servo motor unit and a filter unit A, which is used to selectively transmit the multi-wavelength light. A field stop, positioned at the same location as the aperture stop, is used to block stray light; The chrome-plated pattern is positioned at the same physical point in the optical path as the aperture stop, and the arrangement of the chrome-plated pattern can be either periodic or aperiodic. Dichroic mirrors / beam splitters are used to combine the light beams of the multi-wavelength light into coaxial light; The telecentric lens, employing an object-side telecentric architecture, is used to project the coaxial light onto the target object, thereby suppressing image distortion and achieving balanced illumination distribution across the entire field of view.

2. The multispectral structured optical path system according to claim 1, characterized in that, The operation process of the light source module for generating multi-wavelength light includes: The light source module employs any one of a monochromatic light source, a halogen lamp, a halogen lamp, or a white LED. When using a white LED, it is paired with a filter module. The filter module is used to form a single-color light source, and the center wavelength of the single-color light source is... ,expression: In the formula, This indicates the center wavelength of the filtered monochromatic light. , These are the lower and upper limits of the points, respectively. Indicates wavelength variable, Indicates the output light at wavelength The light intensity at that location, Indicates the wavelength range The integral of the product of the internal wavelength and the output light intensity Indicates the wavelength range The integral of the internal output light intensity, when the light source module uses a white LED paired with a filter module, the filter unit B in the filter module is selected according to the wavelength range determined by the actual measurement requirements.

3. The multispectral structured optical path system according to claim 2, characterized in that, The collimation system module, composed of one or more lenses in any manner, with an aperture stop on its first surface, includes the following operational procedures for collimating the multi-wavelength light rays into a parallel beam: Based on the bandwidth and incident angle range of the multi-wavelength light, select from... A lens group consisting of one or more lenses, in any combination of these lenses, must satisfy the Abbe sine condition. For multi-lens combinations, the lens spacing... Must meet: In the formula, This is the total focal length of the lens group. Let be the focal length of the two lenses, and spherical aberration needs to be corrected using the Seidel aberration formula, expressed as: In the formula, Indicates the physical quantity The summation operation, It is half the aperture of the lens. Indicates the refractive index of the lens. For aperture position parameters, It represents the fourth power of half the aperture of the lens.

4. A multispectral structured optical path system according to claim 3, characterized in that, The operation process of switching the filter motor module, which includes a servo motor unit and filter unit A, for selectively transmitting the multi-wavelength light includes: The servo motor unit is communicatively connected to the host computer software. The host computer software sends control commands to the servo motor unit to drive the filter unit A to rotate. The servo motor unit adopts PID position closed-loop control, and the control law expression is as follows: In the formula, Indicates the servo motor unit at time... Control output quantity, Indicates at time Positional deviation, The proportional coefficient is a parameter of the proportional element in PID control. This indicates that the integral coefficient is a parameter of the integral element in PID control. The derivative coefficients represent the parameters of the derivative element in PID control. Indicates from the initial time At the time Positional deviation The points, It is an integral variable. Indicates positional deviation At any moment rate of change, All PID parameters were tuned using the Ziegler-Nichols method.

5. A multispectral structured optical path system according to claim 4, characterized in that, The operation procedure for setting the field stop at the same position as the aperture stop to block stray light includes: The field stop and the aperture stop are located at the same position, and the central axis deviation is calibrated at the same position. ,expression: In the formula, This indicates the deviation between the central axis of the field stop and the aperture stop. For the center coordinate deviation, the blocked stray light includes, but is not limited to, light reflected from the lens surface, internal scattered light, and ambient stray light. The reflectivity of the light reflected from the lens surface satisfies the Fresnel formula, and the scattering intensity of the internal scattered light follows the Mie scattering model, expressed as: In the formula, Indicates at wavelength of scattering angle is Scattering intensity at that location, The distance from the observation point to the scattering particle. It is the scattering angle. It is the scattering amplitude function. Where is the radius of the scattering particle. The refractive index is given, and the spectral distribution of the ambient stray light conforms to the blackbody radiation model.

6. A multispectral structured optical path system according to claim 5, characterized in that, The operation procedure for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes: The chrome-plated pattern and the aperture stop occupy the same physical position in the optical path, and the center positioning accuracy must satisfy the expression: In the formula, This indicates the positional deviation between the center of the chrome-plated pattern and the center of the aperture stop within the plane. Let be the coordinate dimension of the planar coordinate system. This indicates that the center of the chrome-plated pattern is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the aperture stop is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the chrome-plated pattern is in a plane coordinate system. The coordinates of the direction. This indicates that the center of the aperture stop is in a plane coordinate system. The coordinates of the direction. This means that the positional deviation calculated earlier must be less than or equal to 2 micrometers.

7. A multispectral structured optical path system according to claim 6, characterized in that, The operation procedure for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes: The spatial period of the periodic chrome plating pattern satisfy: In the formula, The spatial period represents the periodicity of the chrome plating pattern. The wavelength of the chrome-plated pattern. It is the angle between the pattern and the axis of the light path. Indicates the included angle Multiplying the sine value by 2, the amplitude transmittance function of the periodic chrome-plated pattern Represented as: In the formula, It is a periodic chrome plating pattern in spatial coordinates Amplitude transmittance at that location The summation operation represents summing over all integers. arrive The corresponding items are accumulated. Fourier coefficients represent frequency Related constants, Imaginary unit, It is an exponential function. This indicates a spatial frequency correlation with the Fourier series. This indicates the spatial variation of the pattern in the tilt direction.

8. A multispectral structured optical path system according to claim 7, characterized in that, The operation procedure for setting the chrome-plated pattern to occupy the same physical position in the optical path as the aperture stop, and arranging the chrome-plated pattern in either a periodic or aperiodic manner, includes: The non-periodic chrome plating pattern is designed using a pseudo-random sequence, and its autocorrelation function is expressed as: In the formula, The autocorrelation function representing a non-periodic chromium plating pattern. The translation amount, The definite integral symbol represents the interval between the two integrals. Perform integration operations on the interval from negative infinity to positive infinity. Represents the integral. These are the lower and upper limits of the points, respectively. Indicates the position of non-periodic chrome plating pattern The amplitude transmittance function at that point Indicates the position of non-periodic chrome plating pattern The amplitude transmittance function at that point It is an integral variable The differential, The wavelength of the chrome-plated pattern is determined by any one of the multi-wavelength light emitted by the light source module or the multi-wavelength light filtered by the filter unit A. The chrome-plated pattern is fabricated on the outer surface of the glass substrate using either laser direct writing or electron beam exposure.

9. A multispectral structured optical path system according to claim 8, characterized in that, The operation procedure of using a dichroic mirror / beam splitter to combine multiple wavelengths of light into coaxial light includes: The multi-wavelength light includes: In the formula, This represents the first wavelength of light. This represents the second wavelength of light. The ellipsis indicates that there are multiple wavelengths of light in between. Indicates the first The incident direction vectors of the light rays of each wavelength are: In the formula, Indicates the first The incident direction vector of light rays of each wavelength. The number representing the wavelength , Indicates the first The incident direction vector of each wavelength of light is in Components in the axial direction, Indicates the first The incident direction vector of each wavelength of light is in Components in the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The component along the axial direction, while the incident direction vector satisfies the following condition: In the formula, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction, Indicates the first The incident direction vector of each wavelength of light is in The square of the component along the axial direction is used to define the outgoing direction vector of the wavelength ray as follows: Then the coaxiality error expression: In the formula, Indicates the first The coaxiality error of light at each wavelength Represents the inverse cosine function. Represents the ideal coaxial direction vector , Indicates the allowable range of coaxiality error. For the first The actual direction vector of the wavelength light rays after beam combining, the total intensity and intensity fluctuation of the coaxial light, expressed as: In the formula, This represents the total light intensity after beam combining. The summation symbol represents the summation of terms from the first term to the second term. The quantities of the items are accumulated. Indicates the first The light intensity of each wavelength of light This represents the amount of light intensity fluctuation. It is time The total light intensity of the combined beam at that time, It is the initial moment The total light intensity of the combined beam, The angle and position of the dichroic mirror / beam splitter, which indicate the allowable range of light intensity fluctuations, are dynamically adjusted according to the requirements of the multi-wavelength light beam combining.

10. A multispectral structured optical path system according to claim 9, characterized in that, The telecentric lens, employing an object-side telecentric architecture, is used to project the coaxial light onto the target object. The operational process for suppressing image distortion and achieving equal illumination distribution across the entire field of view includes: The telecentric lens is mounted at the exit end of the dichroic mirror / beam splitter, and the focal length and position of the telecentric lens are dynamically adjusted according to the measurement distance and field of view requirements to set the field of view angle. With the position of the camera Relational model expression: In the formula, Indicates the field of view. Indicates half-height field of view. Indicates the camera position. Represents the arctangent function, which requires the field of view to be from Replace with At that time, the amount of adjustment of the camera position expression: In the formula, Indicates the amount of lens position adjustment. Indicates half-height field of view. Represents the tangent function. Indicates the initial field of view angle. Indicates the target field of view and the camera position. Adjusted resolution expression: In the formula, Indicates camera position The minimum precision achieved during adjustment. Indicates the field of view. Indicates half-height of the field of view.

Images