Laser scanning device and projection imaging equipment

Abstract

According to the laser scanning device and the projection imaging equipment, the hardware-level distortion correction assembly and the control module of the hardware-level distortion correction assembly are additionally arranged after the galvanometer is reflected, and real-time compensation of the emitting direction of the scanning light beam is achieved. In nonlinear distortion areas such as pillow-shaped distortion and tilt distortion generated by galvanometer scanning, the distortion correction assembly can accurately adjust the deflection angle of a light beam according to a pre-calibrated correction parameter sequence, effectively recover the geometrical shape of a scanning pattern, remarkably improve the linearity of point cloud distribution and the overall imaging precision, and improve the accuracy of point cloud distribution. Moreover, the distortion correction of the full view field can be completed without sacrificing the view field angle or resolution, and a wider effective imaging area and finer image details are ensured. The special distortion correction assembly is integrated in the optical path, so that the dependence on an upper-layer image processing algorithm is reduced, the requirements of the whole system on a high-performance controller and complex software operation are reduced, and the cost benefit and the engineering realizability are better.

Description

Technical Field

[0001] The present disclosure relates to the field of laser scanning technology, and in particular to a laser scanning device and a projection imaging device. Background Art

[0002] A laser scanner is a device that uses a laser beam for measurement, identification, or imaging. As an imaging device, a laser scanner emits a laser beam for imaging, controls the direction of the laser beam (i.e., scanning) through a mechanism, and creates an image on an imaging surface using the residual human vision. However, when a laser scanner is used for imaging, its laser point cloud distribution exhibits nonlinear distortion, such as pincushion distortion and tilt distortion, which distorts the scanned pattern.

[0003] Typically, distortion compensation schemes for scanning patterns use software algorithms to encode the laser sequence of the laser scanning device. This allows the laser to be emitted when scanning into areas with less distortion and to be stopped when scanning into areas with greater distortion, thus ensuring that the image is presented within the less distorted areas. However, this approach sacrifices some of the laser scanning device's field of view and resolution. To achieve the same display parameters, laser scanning devices with distortion compensation have higher hardware requirements than those without. Summary of the Invention

[0004] The embodiments of the present disclosure at least provide a laser scanning device and a projection imaging device to solve the problem of loss of field of view and resolution due to distortion compensation in the prior art.

[0005] In a first aspect, an embodiment of the present disclosure provides a laser scanning device, including a laser emitter, a galvanometer assembly, a distortion correction assembly, and a correction control module; The laser emitter is used to emit a first laser beam; The galvanometer assembly is configured to vibrate at a vibration frequency corresponding to the scanning path, and reflect the first laser beam during the vibration process to obtain a second laser beam; The distortion correction component is used to correct the emission direction of the second laser beam to obtain an emission light beam; The correction control module is used to control the deflection angle of the second laser beam when the distortion correction component deflects the second laser beam according to the correction parameter sequence corresponding to the scanning path.

[0006] In an optional implementation, the correction parameter sequence is determined according to the following steps: Acquire an actual scanned image of the laser scanning device when the distortion correction component is in an initial state, and an ideal scanned image corresponding to the actual scanned image; Determining second scanning points in the ideal scanning image corresponding to a plurality of first scanning points in the actual scanning image; determining a distortion compensation ratio corresponding to the first scanning point based on position information of the first scanning point in an image coordinate system and position information of a second scanning point corresponding to the first scanning point in an image coordinate system; the image coordinate system is a polar coordinate system; and the poles of the image coordinate system coincide with center points of the actual scanned image and the ideal scanned image; The correction parameter sequence is determined based on the scanning timing information of the first scanning point in the scanning path and the distortion compensation ratio corresponding to the first scanning point.

[0007] In an optional embodiment, determining second scanning points in the ideal scanning image that correspond to the plurality of first scanning points in the actual scanning image includes: For any polar axis in the image coordinate system, sort the first scanning points located on the polar axis according to the polar diameters of the first scanning points located on the polar axis in the actual scan image; and sort the third scanning points located on the polar axis according to the polar diameters of the third scanning points located on the polar axis in the ideal scan image; Based on the sorting order of the first scanning points and the third scanning points, a second scanning point corresponding to the first scanning point is determined from the third scanning points.

[0008] In an optional implementation, the first scanning point is a scanning point located at an edge of the actual scanned image; The determining the correction parameter sequence based on the scanning timing information of the first scanning point in the scanning path and the distortion compensation ratio corresponding to the first scanning point includes: Taking the center point of the actual scanned image as a starting point, the actual scanned image is divided into a plurality of correction areas, so that there is a first scanning point in each correction area; For any correction area, determining correction parameters corresponding to each scanning point within the correction area based on the distortion compensation ratio corresponding to the first scanning point; The correction parameter sequence is determined based on the scanning timing information of each scanning point in the scanning path and the correction parameters corresponding to each scanning point.

[0009] In an optional embodiment, the distortion correction component includes a first zoom lens and a second zoom lens; The first zoom lens is used to refract the parallel second laser beam into a converging or diverging third laser beam; The second zoom lens is used to refract the third laser beam into the parallel output light beam; The correction control module is used to control the focal lengths of the first zoom lens and the second zoom lens according to a correction parameter sequence corresponding to the scanning path.

[0010] In an optional implementation, the sum of the first focal length of the first zoom lens and the second focal length of the second zoom lens is equal to the distance between the first zoom lens and the second zoom lens.

[0011] In an optional implementation, the first zoom lens and the second zoom lens are positive lenses; or, the first zoom lens is a negative lens, and the second zoom lens is a positive lens.

[0012] In an optional embodiment, the distortion correction component is located at the very end of the optical path inside the laser scanning device.

[0013] In an optional implementation, the correction control module is a field programmable gate array (FPGA).

[0014] In a second aspect, an embodiment of the present disclosure further provides a projection imaging device, comprising a laser scanning device as described in the first aspect above, or any possible implementation of the first aspect.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of the present disclosure.

[0016] The laser scanning device and projection imaging device provided by the embodiments of the present disclosure realize real-time compensation of the emission direction of the scanning light beam by adding a hardware-level distortion correction component and its control module after the galvanometer reflection. In the nonlinear distortion areas such as pincushion distortion and tilt distortion generated by the galvanometer scanning, the distortion correction component can accurately adjust the beam deflection angle according to a pre-calibrated correction parameter sequence, effectively restore the geometric shape of the scanning pattern, and significantly improve the linearity of the point cloud distribution and the overall imaging accuracy. Unlike the traditional "jump-shot" distortion compensation that selects areas to emit lasers through software algorithms, this device does not need to pause the emission in high-distortion areas, so it can complete the distortion correction of the entire field of view without sacrificing the field of view angle or resolution, ensuring a wider effective imaging area and finer image details. By integrating a dedicated distortion correction component in the optical path, the dependence on the upper-level image processing algorithm is reduced, and the demand for high-performance controllers and complex software operations of the entire system is reduced, which has better cost-effectiveness and engineering feasibility.

[0017] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. The 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 illustrate the technical solutions of the present disclosure. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without inventive effort.

[0019] Figure 1 A schematic diagram of a laser scanning device provided by some embodiments of the present disclosure is shown; Figure 2 A schematic diagram of a distortion correction component provided by some embodiments of the present disclosure is shown; Figure 3 One of the schematic diagrams showing the imaging effects provided by some embodiments of the present disclosure; Figure 4 A second schematic diagram illustrating imaging effects provided by some embodiments of the present disclosure; Figure 5 A schematic diagram of another laser scanning device provided by some embodiments of the present disclosure is shown; Figure 6 A flowchart of a focal length determination sequence provided by some embodiments of the present disclosure is shown; Figure 7 One of the schematic diagrams of scanning points provided by some embodiments of the present disclosure is shown; Figure 8 A second schematic diagram showing scanning points provided by some embodiments of the present disclosure is shown; Figure 9 A schematic diagram of a projection imaging device provided by some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The components of the embodiments of the present disclosure generally described and shown here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present disclosure is not intended to limit the scope of the present disclosure for protection, but merely represents the selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present disclosure.

[0021] Research has found that images scanned by laser scanners can be distorted. Typically, distortion compensation schemes for scanning patterns use software algorithms to encode the laser sequence within the laser scanner. This allows the laser to be emitted when it scans into areas with less distortion and to be deactivated when it scans into areas with greater distortion, thus ensuring that the image is presented within the less distorted area. However, this approach sacrifices some of the laser scanner's field of view and resolution. To achieve the same display parameters, laser scanners with distortion compensation have higher hardware requirements than those without.

[0022] Based on the above research, the present disclosure provides a laser scanning device and a projection imaging device. By adding a hardware-level distortion correction component and its control module after the galvanometer reflection, real-time compensation for the emission direction of the scanning beam is achieved. In the nonlinear distortion areas such as pincushion distortion and tilt distortion generated by the galvanometer scanning, the distortion correction component can accurately adjust the beam deflection angle according to a pre-calibrated correction parameter sequence, effectively restore the geometric shape of the scanning pattern, and significantly improve the linearity of the point cloud distribution and the overall imaging accuracy. Unlike the traditional "jump-shot" distortion compensation that selectively emits laser light in a certain area through a software algorithm, this device does not need to pause the emission in the high-distortion area, so it can complete the distortion correction of the entire field of view without sacrificing the field of view angle or resolution, ensuring a wider effective imaging area and finer image details. By integrating a dedicated distortion correction component in the optical path, the dependence on the upper-level image processing algorithm is reduced, and the demand for high-performance controllers and complex software operations of the entire system is reduced, which has better cost-effectiveness and engineering feasibility.

[0023] The defects in the above solutions are the results obtained by the inventors after practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed by this disclosure for the above problems below should be the contributions made by the inventors to this disclosure during the disclosure process.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0025] See also Figure 1 FIG. 1 is a schematic diagram of a laser scanning device provided by an embodiment of the present disclosure, wherein the device includes a laser emitter 10 , a galvanometer assembly 20 , a distortion correction assembly 30 , and a correction control module 40 ; The laser emitter 10 is used to emit a first laser beam; The galvanometer assembly 20 is configured to vibrate at a vibration frequency corresponding to the scanning path, and reflect the first laser beam during the vibration process to obtain a second laser beam; The distortion correction component 30 is used to correct the emission direction of the second laser beam to obtain an emission beam; The correction control module is used to control the deflection angle of the second laser beam when the distortion correction component deflects the second laser beam according to the correction parameter sequence corresponding to the scanning path.

[0026] The laser emitter 10 can be used to emit a first laser beam, i.e., the initial laser light. The laser emitter 10 can be a laser diode, a solid-state laser, a semiconductor pump laser, a fiber laser, or the like. Its output wavelengths can include red light (approximately 650 nm), green light (approximately 532 nm), blue light (approximately 450 nm), and the like. The laser emitter 10 can be controlled by a control signal to output laser beams of different colors. For example, the laser emitter 10 can include an RGB laser diode and an optical path for collimation and beam combining.

[0027] The galvanometer assembly 20 can control one or two mirrors to swing in the horizontal and / or vertical directions through electromagnetic drive to achieve control of the laser direction. In a possible embodiment, the galvanometer assembly 20 can be a dual-axis galvanometer for achieving two-dimensional plane scanning.

[0028] The first laser beam emitted by the laser emitter 10 is reflected by the galvanometer assembly 20 to form a second laser beam. The direction of the second laser beam changes with the vibration of the galvanometer assembly 20, forming a scanning trajectory. The galvanometer assembly 20 can control the scanning mode of the laser beam. Exemplary scanning modes include Lissajous scanning, raster scanning, spiral scanning, and linear scanning.

[0029] During scanning, a laser scanning sequence can be generated based on the image to be displayed and the scanning path. Laser emitter 10 can be controlled based on the laser scanning sequence to emit laser beams of corresponding colors at different times. In the disclosed embodiment, distortion correction does not require modifying the laser scanning sequence. Instead, distortion correction is performed directly at the hardware level by adjusting the emission direction of the second laser beam through distortion correction component 30.

[0030] The distortion correction assembly 30 can correct the emission direction of the second laser beam, thereby reducing or offsetting the nonlinear distortion caused by the galvanometer scanning. Exemplarily, the distortion correction assembly 30 may include a controllable liquid crystal light modulator, an electro-optical modulator, a micro-motor-driven reflector, a deformable reflective surface assembly, a variable lens array, and the like.

[0031] In one possible embodiment, the distortion correction component 30 includes a first zoom lens 31 and a second zoom lens 32; the first zoom lens 31 is used to refract the parallel second laser beam into a converging or diverging third laser beam; the second zoom lens 32 is used to refract the third laser beam into the parallel outgoing light beam; the correction control module 40 is used to control the focal length of the first zoom lens 31 and the second zoom lens 32 according to the correction parameter sequence corresponding to the scanning path.

[0032] The correction control module 40 can adjust the focal lengths of the first zoom lens 31 and the second zoom lens 32 to control the degree of light beam divergence or convergence, thereby correcting the nonlinear distortion of laser scanning.

[0033] The correction control module 40 can be a device with certain computing capabilities, such as a processor, a field programmable gate array (FPGA), a single-chip microcomputer, or a system on a chip (SOC). It can issue control instructions based on the correction parameter sequence corresponding to the scanning path to control the focal lengths of the first zoom lens 31 and the second zoom lens 32.

[0034] Illustratively, the first zoom lens 31 may be a convex lens or a concave lens structure, or a zoom lens group with adjustable position (such as a movable lens structure).

[0035] Exemplarily, the second zoom lens 32 can form an interlaced zoom combination with the first lens, and achieve compensation under different incident angles through synchronous zooming, and its internal optical spacing or focal length can be adjusted by a servo motor or a micro actuator.

[0036] Exemplarily, the first zoom lens 31 and the second zoom lens 32 may be electric zoom lenses, liquid zoom lenses, liquid crystal zoom lenses, etc.

[0037] The first zoom lens 31 refracts the parallel second laser beam into a third laser beam with a certain divergence or convergence angle. This provides a primary adjustment for the divergence or convergence of the beam. The second zoom lens 32 refracts the third laser beam, processed by the first lens, into a parallel outgoing beam, restoring its collimation and making it suitable for precise imaging.

[0038] In a possible implementation manner, the position of the first zoom lens 31 and / or the second zoom lens 32 is adjustable, and the correction control module 40 adaptively adjusts the focal length and position according to the required deflection angle.

[0039] In a possible implementation manner, the position of the first zoom lens 31 and / or the second zoom lens 32 is not adjustable, and the correction control module 40 can adjust the focal length according to a required deflection angle.

[0040] See also Figure 2 Figure 2 is a schematic diagram of a distortion correction assembly 30 provided in an embodiment of the present disclosure. In this embodiment, both the first zoom lens 31 and the second zoom lens are positive lenses (i.e., convex lenses). The second laser beam reflected by the galvanometer assembly 20 enters the first zoom lens 31, which converges the parallel second laser beam to a focal point. The second laser beam then diverges again at the focal point and enters the second zoom lens 32, where it is refracted back into a parallel outgoing beam.

[0041] In this embodiment, the sum of the first focal length of the first zoom lens 31 and the second focal length of the second zoom lens 32 is equal to the distance between the first zoom lens 31 and the second zoom lens 32. In this case, the first ratio is equal to the second ratio. The first ratio is the ratio between the tangent of the angle between the outgoing light beam and the optical axis and the tangent of the angle between the second laser beam and the optical axis; the second ratio is the ratio between the first focal length and the second focal length.

[0042] From the above, it can be seen that when the distance between the first zoom lens 31 and the second zoom lens 32 remains unchanged, by adjusting the focal lengths of the first zoom lens 31 and the second zoom lens 32, the angle between the outgoing light beam and the optical axis can be adjusted, thereby correcting the distortion.

[0043] In one possible implementation, the first zoom lens 31 is a negative lens (i.e., a concave lens), and the second zoom lens is a positive lens. This prevents the first zoom lens 31 from forming an actual focal point, and the third laser beam is not focused between the two zoom lenses. Compared to an embodiment in which both the first zoom lens 31 and the second zoom lens 32 are positive lenses, the two zoom lenses can be placed closer together, and the distance between the first zoom lens 31 and the second zoom lens 32 is shortened, making the overall system shorter and suitable for applications with limited space.

[0044] In a possible implementation, the distortion correction component 30 may be located at the very end of the optical path within the laser scanning device to reduce the influence of the distortion correction component 30 on other components in the optical path.

[0045] When the correction control module 40 controls the deflection angle of the second laser beam, the correction control module 40 may determine the control parameters required at each time point according to the correction parameter sequence, and thereby send control instructions corresponding to the control parameters.

[0046] The correction parameter sequence described above can refer to an ordered set of control parameters corresponding to the laser beam's scanning path. These parameters are used to dynamically adjust the operating state of the distortion correction component, thereby achieving real-time compensation for optical path distortion generated during the scanning process. These control parameters can be arranged in a sequence, with each parameter corresponding to a specific scanning state or scanning angle, such as a specific moment, a specific galvanometer mirror angle, or a specific spatial position.

[0047] The correction parameters may refer to control values ​​related to the optical system, and may include, for example, the focal length adjustment value of the zoom lens, the relative position adjustment amount of the lens group, the correction coefficient of the deflection angle, the voltage value of the control electrical signal, etc.

[0048] This correction parameter sequence can be obtained through offline calibration or generated through pre-set modeling calculations. For example, the system can scan a standard pattern at the factory and record the actual deviations to generate the corresponding correction parameters. During the scanning process, the control module sequentially retrieves the corresponding correction values ​​from the correction parameter sequence according to the scanning progress and applies them to the distortion correction component to ensure that each scan point is correctly corrected to the target position.

[0049] In one possible implementation, the correction parameter sequence may be determined by the following steps: Acquire an actual scanned image of the laser scanning device when the distortion correction component is in an initial state, and an ideal scanned image corresponding to the actual scanned image; Determining second scanning points in the ideal scanning image corresponding to a plurality of first scanning points in the actual scanning image; determining a distortion compensation ratio corresponding to the first scanning point based on position information of the first scanning point in an image coordinate system and position information of a second scanning point corresponding to the first scanning point in an image coordinate system; the image coordinate system is a polar coordinate system; and the poles of the image coordinate system coincide with center points of the actual scanned image and the ideal scanned image; The correction parameter sequence is determined based on the scanning timing information of the first scanning point in the scanning path and the distortion compensation ratio corresponding to the first scanning point.

[0050] The first scanning point may be a scanning point in an actual scanned image, i.e., a distorted position; the second scanning point may be the position corresponding to the first scanning point in an ideal scanned image. The position of each scanning point may be defined by a polar radius and a polar angle. In this embodiment, the scanning method may be a Lissajous scanning method.

[0051] During the image acquisition process, an actual scanned image, with the distortion correction component not in effect (i.e., in its initial state), and an ideal scanned image corresponding to the image (e.g., a computer-generated image or correction template) can be obtained. Subsequently, the corresponding second scanned points in the idealized image for multiple first scanned points in the actual image can be determined, and a one-to-one mapping can be established.

[0052] After obtaining the mapping relationship, the distortion compensation ratio can be calculated. For example, the polar radius ratio of the first scanning point and the corresponding second scanning point can be calculated, indicating the degree of "scaling" or "expansion" required for the scanning point in the current direction.

[0053] Afterwards, the scan timing information can be combined to generate a correction parameter sequence. The scan path is sequential and periodic. For example, the Lissajous scanning method uses two orthogonal sinusoidal drive signals to control the scanning mirror, thereby generating a Lissajous curve. The distortion compensation ratio of each scan point can be mapped to its scanning sequence time point, forming a "correction parameter sequence" that is ultimately used to drive the distortion correction component.

[0054] In a possible implementation, the second scanning points corresponding to the plurality of first scanning points in the actual scanning image in the ideal scanning image may be determined according to the following steps: For any polar axis in the image coordinate system, sort the first scanning points located on the polar axis according to the polar diameters of the first scanning points located on the polar axis in the actual scan image; and sort the third scanning points located on the polar axis according to the polar diameters of the third scanning points located on the polar axis in the ideal scan image; Based on the sorting order of the first scanning points and the third scanning points, a second scanning point corresponding to the first scanning point is determined from the third scanning points.

[0055] In this way, this embodiment does not require feature point extraction or geometric alignment, and only achieves point correspondence through coordinate sorting, which is simple to calculate, stable matching, and highly adaptable.

[0056] In one possible implementation, the first scanning point is a scanning point located at an edge of the actual scanned image. Determining the correction parameter sequence based on scanning timing information of the first scanning point along the scanning path and a distortion compensation ratio corresponding to the first scanning point includes: Taking the center point of the actual scanned image as a starting point, the actual scanned image is divided into a plurality of correction areas, so that there is a first scanning point in each correction area; For any correction area, determining correction parameters corresponding to each scanning point within the correction area based on the distortion compensation ratio corresponding to the first scanning point; The correction parameter sequence is determined based on the scanning timing information of each scanning point in the scanning path and the correction parameters corresponding to each scanning point.

[0057] In this embodiment, because actual distortion is most severe at the edges of the image, error data from edge regions is prioritized. Typically, the degree of image distortion varies across polar angle ranges. Therefore, the actual scanned image can be divided into multiple correction regions. Each correction region can include a first scanning point, which serves as the representative point of the correction region. The correction parameters for this first scanning point are used to generate correction parameters corresponding to each scanning point within the correction region. Finally, based on the scan timing information of the scan path, time mapping is performed, and the correction parameters are arranged according to the scan timing. This constructs a time series correction parameter sequence for use by the correction control module 40.

[0058] When using the distortion compensation ratio corresponding to the first scanning point to determine the correction parameters corresponding to each scanning point in the correction area, the compensation ratio of the edge can be used as the representative value of the area, and the correction parameters corresponding to the first scanning point can be directly used as the correction parameters of each scanning point in the correction area, thereby reducing the frequency of change of the correction parameters and reducing imaging blur caused by rapid changes in the focal length of the lens in the distortion correction component 30.

[0059] Alternatively, linear interpolation or weighted interpolation may be performed based on the distances from other points in the region to the center or edge to generate correction parameters for each point in the region, thereby reducing the amount of calculation required to determine the correction parameters.

[0060] See also Figure 3 as well as Figure 4 , Figure 3 One of the schematic diagrams showing the imaging effects provided by some embodiments of the present disclosure; Figure 4 A second schematic diagram showing the imaging effects provided by some embodiments of the present disclosure. Figure 3 and Figure 4 In the figure, the solid rectangular box represents the imaging effect of the laser scanning device provided by the embodiment of the present disclosure, the dotted rectangular box represents the imaging effect using software algorithm distortion compensation in the related art, and the curved line enclosed portion represents the imaging effect without distortion compensation in the related art. Figure 3 The curve enclosed part is the imaging effect of the galvanometer scanning in parallel with the normal direction and the laser incident direction when the galvanometer is stationary. Figure 4 The portion surrounded by the curve is the imaging effect obtained by scanning the two non-parallel images. It can be seen that the laser scanning device provided by the embodiment of the present disclosure can significantly improve the field of view and resolution.

[0061] The present disclosure provides a laser scanning device, which realizes real-time compensation of the emission direction of the scanning light beam by adding a hardware-level distortion correction component and its control module after the galvanometer reflection. In the nonlinear distortion areas such as pincushion distortion and tilt distortion generated by the galvanometer scanning, the distortion correction component can accurately adjust the beam deflection angle according to the pre-calibrated correction parameter sequence, effectively restore the geometric shape of the scanning pattern, and significantly improve the linearity of the point cloud distribution and the overall imaging accuracy. Unlike the traditional "jump-shot" distortion compensation that selects areas to emit lasers through software algorithms, this device does not need to pause the emission in high-distortion areas, so it can complete the distortion correction of the entire field of view without sacrificing the field of view angle or resolution, ensuring a wider effective imaging area and finer image details. By integrating a dedicated distortion correction component in the optical path, the dependence on the upper-level image processing algorithm is reduced, and the demand for high-performance controllers and complex software operations of the entire system is reduced, which has better cost-effectiveness and engineering feasibility.

[0062] See also Figure 5 Figure 2 is a schematic diagram of another laser scanning device provided by an embodiment of the present disclosure. The device includes a field programmable gate array (FPGA), a laser driver board, a digital-to-analog converter (DAC), a laser, a galvanometer, two zoom lenses, and two zoom lens driver boards.

[0063] Based on the time-sequential laser output color information sequence and galvanometer drive voltage sequence generated by image encoding, the FPGA applies corresponding digital signals to the laser driver board and DAC module. The laser driver board controls the current flowing through the three-color laser according to the digital signals from the FPGA, thereby achieving different color outputs. The DAC module receives the digital signals from the FPGA and outputs the corresponding voltage to drive the galvanometer to vibrate and scan.

[0064] According to the focal length coding sequence, the FPGA outputs a digital signal to the zoom lens driver board, thereby controlling the electric field distribution on the zoom lens to change the focal length of the zoom lens, thereby correcting the angle between the outgoing light and the optical axis, and thus correcting the distortion.

[0065] See also Figure 6 、 Figure 7 , Figure 6 A flowchart of determining a focal length sequence provided in some embodiments of the present disclosure is provided. Figure 7 This is one of the schematic diagrams of scanning points provided in some embodiments of the present disclosure.

[0066] Figure 6The steps of determining the correction parameter sequence in the embodiment include: encoding the ideal scanning pattern and the actual scanning pattern to obtain two sets of pixel indexes based on time sequence. Given the spatial size of the pixel, the pixel position can be obtained according to the pixel index; the plane where the scanning pattern is located establishes a polar coordinate system with the center of the pattern as the origin, discretizes the angular coordinate differential, and counts the number of pixel indices in each set of angular coordinate intervals (i.e., the number of pixel indices in each set of angular coordinate intervals) in the two sets of pixel indices. ) pixel index; for the two sets of pixel indexes in each angular coordinate interval, sort them according to the radius coordinates, and establish two sets of pixel indexes to establish a mapping, that is, map from small radius coordinates to large radius coordinates in sequence, as shown in Figure ( Figure 7 ) Take three points as an example, namely a, b, and c are points in the ideal scanning pattern, and A, B, and C are points in the actual scanning pattern, and the mappings of A→a, B→b, and C→c are obtained; for each group of mappings, the scaling ratios S1=Oa / OA, S2=Ob / OB, and S3=Oc / OC are calculated, and all the calculated scaling ratios are arranged into a sequence according to the initial encoding time sequence; given the spacing L between the two groups of zoom lenses, taking the two groups of zoom lenses as positive lenses as an example, corresponding to the above-mentioned scaling ratio sequence, taking S1 as an example, the focal length of lens 1 (that is, the first zoom lens 31) is (S1*L) / (1+S1), and the focal length of lens 2 (that is, the second zoom lens 32) is L / (1+S1), that is, the focal length sequence of lens 1 and lens 2 according to the initial encoding time sequence is obtained.

[0067] See also Figure 8 , Figure 8 This is a second schematic diagram of scanning points provided in some embodiments of the present disclosure. Figure 8 In the figure, scanning point d is the scanning point at the edge of the ideal scanning pattern, D is the scanning point at the edge of the actual scanning pattern, and the angular coordinate interval is Based on Od / OD, the focal length of each scanning point in the angular coordinate interval can be determined.

[0068] Based on the same inventive concept, the present disclosure also provides a projection imaging device. Figure 9 , is a projection imaging device provided by an embodiment of the present disclosure, and the device includes the laser scanning device in any of the above embodiments.

[0069] In one possible implementation, the projection imaging device may be an in-vehicle head-up display (HUD) system, an augmented reality (AR) or mixed reality (MR) system, a portable laser projector, a medical image assistance system, a laser lighting demonstration and stage display system, etc.

[0070] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present disclosure, which are used to illustrate the technical solutions of the present disclosure, rather than to limit them. The scope of protection of the present disclosure is not limited thereto. Although the present disclosure has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed in the present disclosure, or replace some of the technical features therein with equivalents. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure, and should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A laser scanning device, characterized in that: It includes a laser emitter, a galvanometer assembly, a distortion correction assembly and a correction control module; The laser emitter is used to emit a first laser beam; The galvanometer assembly is configured to vibrate at a vibration frequency corresponding to the scanning path, and reflect the first laser beam during the vibration process to obtain a second laser beam; The distortion correction component is used to correct the emission direction of the second laser beam to obtain an emission light beam; The correction control module is used to control the deflection angle of the second laser beam when the distortion correction component deflects the second laser beam according to the correction parameter sequence corresponding to the scanning path.

2. The laser scanning device according to claim 1, wherein: The correction parameter sequence is determined according to the following steps: Acquire an actual scanned image of the laser scanning device when the distortion correction component is in an initial state, and an ideal scanned image corresponding to the actual scanned image; Determining second scanning points in the ideal scanning image corresponding to a plurality of first scanning points in the actual scanning image; determining a distortion compensation ratio corresponding to the first scanning point based on position information of the first scanning point in an image coordinate system and position information of a second scanning point corresponding to the first scanning point in an image coordinate system; the image coordinate system is a polar coordinate system; and the poles of the image coordinate system coincide with center points of the actual scanned image and the ideal scanned image; The correction parameter sequence is determined based on the scanning timing information of the first scanning point in the scanning path and the distortion compensation ratio corresponding to the first scanning point.

3. The laser scanning device according to claim 2, wherein: The determining of second scanning points in the ideal scanning image corresponding to the plurality of first scanning points in the actual scanning image includes: For any polar axis in the image coordinate system, sort the first scanning points located on the polar axis according to the polar diameters of the first scanning points located on the polar axis in the actual scan image; and sort the third scanning points located on the polar axis according to the polar diameters of the third scanning points located on the polar axis in the ideal scan image; Based on the sorting order of the first scanning points and the third scanning points, a second scanning point corresponding to the first scanning point is determined from the third scanning points.

4. The laser scanning device according to claim 2, wherein: The first scanning point is a scanning point located at the edge of the actual scanned image; The determining the correction parameter sequence based on the scanning timing information of the first scanning point in the scanning path and the distortion compensation ratio corresponding to the first scanning point includes: Taking the center point of the actual scanned image as a starting point, the actual scanned image is divided into a plurality of correction areas, so that there is a first scanning point in each correction area; For any correction area, determining correction parameters corresponding to each scanning point within the correction area based on the distortion compensation ratio corresponding to the first scanning point; The correction parameter sequence is determined based on the scanning timing information of each scanning point in the scanning path and the correction parameters corresponding to each scanning point.

5. The laser scanning device according to any one of claims 1 to 4, characterized in that: The distortion correction assembly includes a first zoom lens and a second zoom lens; The first zoom lens is used to refract the parallel second laser beam into a converging or diverging third laser beam; The second zoom lens is used to refract the third laser beam into the parallel output light beam; The correction control module is used to control the focal lengths of the first zoom lens and the second zoom lens according to a correction parameter sequence corresponding to the scanning path.

6. The laser scanning device according to claim 5, characterized in that: A sum of a first focal length of the first zoom lens and a second focal length of the second zoom lens is equal to a distance between the first zoom lens and the second zoom lens.

7. The laser scanning device according to claim 5, characterized in that: The first zoom lens and the second zoom lens are positive lenses; or the first zoom lens is a negative lens and the second zoom lens is a positive lens.

8. The laser scanning device according to claim 5, wherein: The distortion correction component is located at the end of the optical path inside the laser scanning device.

9. The laser scanning device according to claim 1, wherein: The correction control module is a field programmable gate array FPGA.

10. A projection imaging device, characterized in that: Comprising the laser scanning device according to any one of claims 1 to 9.

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