Dynamic laser speckle projection device

Abstract

The present invention provides a dynamic laser speckle projection device, comprising a laser emitter, a rotating diffraction module, a lens, and a carrier plate. The laser emitter is configured to emit a laser beam; the carrier plate is configured to connect the laser emitter, the rotating diffraction module, and the lens; the laser emitter, the rotating diffraction module, and the lens are sequentially arranged in the optical path of the laser beam; the rotating diffraction module comprises an optical diffraction device and a rotating motor; the optical diffraction device is configured to diffract the laser beam to form a speckle pattern; the optical diffraction device is disposed on the motor shaft of the rotating motor; the rotating motor rotates at an adjustable first speed, driving the optical diffraction device to rotate; each laser beam forms a different speckle pattern after passing through the rotating optical diffraction device; and the lens is configured to scale and / or focus the speckle pattern. The dynamic laser speckle projection device provided by the present invention can solve the problem of missing point clouds in binocular vision imaging.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a dynamic laser speckle projection device. Background Art

[0002] With rapid advances in imaging technology and computer algorithms, machine vision is playing an increasingly important role in industrial production and smart living, particularly in areas such as intelligent driving, automated assembly lines, facial recognition, and intelligent robotics. Machine vision has many technical branches, including binocular stereo vision, which simulates the imaging principle of the human eye and uses parallax to recover image depth information for 3D reconstruction. While it offers the advantages of high efficiency and non-contact ranging, it still suffers from the problem of missing point clouds.

[0003] Existing technologies use binocular stereo vision combined with active projection structured light technology, supporting structured light projection in various patterns, including dot, line, and mesh. However, the projected structured light is generally static, and a single structured light source cannot meet the requirements of multiple projection targets, effectively preventing point cloud loss. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a dynamic laser speckle projection device.

[0005] The present invention provides a dynamic laser speckle projection device, comprising a laser emitter, a rotating diffraction module, a lens, and a carrier plate; wherein:

[0006] The laser emitter is used to emit a laser beam;

[0007] The carrier plate is used to connect the laser emitter, the rotation diffraction module and the lens; the laser emitter, the rotation diffraction module and the lens are sequentially arranged in the optical path direction of the laser beam;

[0008] The rotating diffraction module includes an optical diffraction device and a rotating motor; the optical diffraction device is used to diffract the laser beam to form a speckle pattern; the optical diffraction device is disposed on a motor shaft of the rotating motor; the rotating motor drives the optical diffraction device to rotate when rotating at an adjustable first speed; each laser beam forms a different speckle pattern after passing through the rotating optical diffraction device;

[0009] The lens is used to scale and / or focus the speckle pattern.

[0010] According to a dynamic laser speckle projection device provided by the present invention, the optical path direction of the laser beam is parallel to the rotation axis of the optical diffraction element.

[0011] According to a dynamic laser speckle projection device provided by the present invention, the device further includes:

[0012] An electric pan-tilt platform is connected to the object carrier and is used to drive the laser emitter, the rotating diffraction module and the lens to rotate in the horizontal direction.

[0013] According to a dynamic laser speckle projection device provided by the present invention, the distances between the laser emitter, the rotating diffraction module, the lens and the electric pan-tilt head are adjustable.

[0014] According to a dynamic laser speckle projection device provided by the present invention, the laser emitter emits a laser beam based on an adjustable first frequency.

[0015] According to a dynamic laser speckle projection device provided by the present invention, the trigger signal of the laser emitter is turned on and off according to the preset frequency.

[0016] According to the dynamic laser speckle projection device provided by the present invention, the duty cycle of the trigger signal can be scaled.

[0017] According to a dynamic laser speckle projection device provided by the present invention, the laser emitter includes any one of the following: a single semiconductor laser LD; multiple groups of LDs; and a vertical cavity surface emitting laser VCSEL.

[0018] According to a dynamic laser speckle projection device provided by the present invention, the lens includes a voice coil motor, a convex lens, a first concave lens and a second concave lens; wherein:

[0019] The voice coil motor drives at least one of the convex lens, the first concave lens, and the second concave lens to move, so as to adjust the distance between adjacent lenses.

[0020] According to a dynamic laser speckle projection device provided by the present invention, the electric pan-tilt platform includes a pan-tilt platform base, a pan-tilt platform bracket, a first servo, a second servo, and a loading plate; wherein:

[0021] The first servo drives the laser emitter, the rotating diffraction module and the lens to rotate in the x-axis direction;

[0022] The second steering gear drives the laser emitter, the rotating diffraction module and the lens to rotate in the y-axis direction.

[0023] The dynamic laser speckle projection device provided by the present invention rotates an optical diffraction device by rotating a rotary motor at an adjustable first speed. This drives the rotation of the device, so that the laser beam generated by the laser emitter forms different speckle patterns after passing through the rotating optical diffraction module. After zooming and focusing through the lens, the device outputs a speckle coding pattern with adjustable speckle density, spot size, and area size. This can meet the three-dimensional data measurement requirements of binocular cameras for different target objects, facilitate pixel matching in binocular cameras, and solve the problem of missing point clouds in binocular visual imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is one of the structural schematic diagrams of the dynamic laser speckle projection device provided by the present invention;

[0026] Figure 2 This is the second structural diagram of the dynamic laser speckle projection device provided by the present invention;

[0027] Figure 3 is a schematic diagram of a laser beam passing through an optical diffraction device in the present invention;

[0028] Figure 4 It is a schematic diagram of multiple exposures of the laser beam after passing through the rotating diffraction module within one exposure cycle in the present invention;

[0029] Figure 5 is a schematic diagram of the laser speckle pattern of the present invention after lens focusing and zooming;

[0030] Figure 6 It is a schematic structural diagram of a lens in the dynamic laser speckle projection device provided by the present invention;

[0031] Figure 7 It is a side view of various components arranged on the object carrier plate in the dynamic laser speckle projection device provided by the present invention. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] The following combination Figure 1-Figure 7 The dynamic laser speckle projection device of the present invention is described.

[0034] Figure 1 This is one of the structural diagrams of the dynamic laser speckle projection device provided by the present invention, such as Figure 1 As shown, the dynamic laser speckle projection device 1000 includes a laser emitter 100, a rotating diffraction module 200, a lens 300 and a carrier plate 401; wherein:

[0035] The laser emitter 100 is used to emit a laser beam;

[0036] The carrier plate 401 is used to connect the laser emitter 100, the rotation diffraction module 200 and the lens 300; the laser emitter 100, the rotation diffraction module 200 and the lens 300 are sequentially arranged in the optical path direction of the laser beam;

[0037] The rotating diffraction module 200 includes an optical diffraction element (DOE) 201 and a rotating motor 202. The optical diffraction element 201 is used to diffract the laser beam to form a speckle pattern. The optical diffraction element 201 is disposed on the motor shaft of the rotating motor 202. The rotating motor 202 rotates at an adjustable first speed, driving the optical diffraction element 201 to rotate. Each laser beam forms a different speckle pattern after passing through the rotating optical diffraction element 201.

[0038] The lens 300 is used to scale and / or focus the speckle pattern.

[0039] Optionally, the optical path direction of the laser beam is parallel to the rotation axis of the optical diffraction device 201. The laser beam passes through the optical diffraction device 201 and the lens 300 in sequence to form a dynamic speckle pattern, and is finally projected onto the target object.

[0040] Figure 3 is a schematic diagram of a laser beam passing through an optical diffraction device in the present invention; Figure 4 It is a schematic diagram of multiple exposures of the laser beam after passing through the rotating diffraction module within one exposure cycle in the present invention; Figure 5 FIG is a schematic diagram of the laser speckle pattern in the present invention after lens focusing and zooming. Figure 3 and Figure 4 As shown, the rotating diffraction module 200 diffracts the laser beam to form a dynamic speckle pattern; Figure 5 As shown, the lens 300 focuses and zooms the dynamic speckle pattern.

[0041] Optionally, the laser emitter 100 emits a laser beam based on an adjustable first frequency.

[0042] Optionally, the trigger signal of the laser emitter 100 is turned on and off at the preset frequency. The laser emitter 100 flashes at a first frequency (e.g., frequency f1). The duty cycle of the trigger signal is set to 0.1 by default. The duty cycle of the trigger signal can be scaled based on the actual speckle projection effect. By changing the flashing frequency f1 of the laser emitter 100, the number of speckles in a single camera exposure can be adjusted. When adjusting the laser emitter pulse signal, the duty cycle of the laser trigger signal is reduced to change the dynamic speckle pattern from an arc pattern to a dot pattern.

[0043] Optionally, the laser emitter 100 may include any one of the following: a single semiconductor laser (LaserDiode, LD); multiple groups of LDs; a vertical-cavity surface-emitting laser (Vertical-Cavity Surface-Emitting Laser, VCSEL).

[0044] Optionally, the optical diffraction device 201 rotates at a first speed driven by a rotary motor. During a single exposure cycle t of the binocular camera, the laser flashes f1·t times, projecting f1·t speckle patterns. Because the optical diffraction device 201 rotates continuously, each projected pattern is different, and a single camera exposure is equivalent to projecting f1·t groups of scattered spots. By changing the laser emitter flashing frequency f1, the number of scattered spots in a single exposure cycle can be adjusted. By changing the first speed of the optical diffraction device 201, the distance between the scattered spots can be adjusted. By adjusting the rotary motor drive current, the first speed of the optical diffraction device 201 (e.g., speed n1) is changed, thereby controlling the distance r between the speckle light points, and the speckle distance r is inversely proportional to the speed n1.

[0045] The dynamic laser speckle projection device provided by the present invention rotates an optical diffraction device by rotating a rotary motor at an adjustable first speed. This drives the rotation of the device, so that the laser beam generated by the laser emitter forms different speckle patterns after passing through the rotating optical diffraction module. After zooming and focusing through the lens, the device outputs a speckle coding pattern with adjustable speckle density, spot size, and area size. This can meet the three-dimensional data measurement requirements of binocular cameras for different target objects, facilitate pixel matching in binocular cameras, and solve the problem of missing point clouds in binocular visual imaging.

[0046] Figure 2 This is the second structural diagram of the dynamic laser speckle projection device provided by the present invention, such as Figure 2 As shown, the dynamic laser speckle projection device 2000 includes a laser emitter 100, a rotating diffraction module 200, a lens 300, a carrier plate 401 and an electric pan-tilt head 400; wherein:

[0047] The laser emitter 100 is used to emit a laser beam;

[0048] The carrier plate 401 is used to connect the laser emitter 100, the rotation diffraction module 200 and the lens 300; the laser emitter 100, the rotation diffraction module 200 and the lens 300 are sequentially arranged in the optical path direction of the laser beam;

[0049] The rotating diffraction module 200 includes an optical diffraction device 201 and a rotating motor 202. The optical diffraction device 201 is used to diffract the laser beam to form a speckle pattern. The optical diffraction device 201 is disposed on the motor shaft of the rotating motor 202. When the rotating motor 202 rotates at an adjustable first speed, it drives the optical diffraction device 201 to rotate. Each laser beam forms a different speckle pattern after passing through the rotating optical diffraction device 201.

[0050] The lens 300 is used to scale and / or focus the speckle pattern;

[0051] The electric pan-tilt platform 400 is connected to the object carrier 401 and is used to drive the laser emitter 100 , the rotating diffraction module 200 and the lens 300 to rotate horizontally to adjust the position of the speckle pattern.

[0052] Optionally, the distances between the laser emitter 100, the rotating diffraction module 200, the lens 300 and the electric pan-tilt platform 400 are adjustable. The electric pan-tilt platform 400 drives the entire optical path to rotate on a two-dimensional plane.

[0053] Optionally, the electric pan / tilt head 400 includes a pan / tilt head base 404, a pan / tilt head bracket 402, a first servo 403, a second servo 405, and a loading plate 401. The first servo 403 drives the laser emitter 100, the rotating diffraction module 200, and the lens 300 to rotate along the x-axis; the second servo 405 drives the laser emitter 100, the rotating diffraction module 200, and the lens 300 to rotate along the y-axis. The first servo 403 and the second servo 405 can respectively drive the laser emitter 100, the rotating diffraction module 200, and the lens 300 to rotate along the x-axis or y-axis, thereby changing the position of the entire speckle projection area.

[0054] The dynamic laser speckle projection device provided by the present invention rotates an optical diffraction device by rotating a rotary motor at an adjustable first speed. The laser beam generated by a laser emitter passes through the optical diffraction device to form dynamic speckles. The laser beam is then zoomed and focused by a lens. Finally, the projection position is controlled by an electric pan-tilt head. The device outputs a speckle coding pattern with adjustable speckle density, spot size, area size, and center position. This meets the three-dimensional data measurement requirements of binocular cameras for different target objects and can solve the problem of missing point clouds in binocular visual imaging.

[0055] The dynamic laser speckle projection device provided by the present invention has significant advantages over existing technologies in that: (1) when acting on targets with different surface conditions, the imaging effect of the object is good, and the problem of missing point clouds in traditional binocular vision imaging can be solved; (2) the speckle pattern is flexible and variable, and the projection size, density and position of the laser speckle pattern can be changed according to actual needs, which can solve the problem of poor speckle projection effect caused by differences in target size and target position in traditional structured light; (3) compared with the method of producing speckle patterns by computer simulation, the present invention has a simple structure, low cost, a large number of projected speckles, low computational requirements, and high light utilization efficiency.

[0056] Figure 6 FIG. 1 is a schematic structural diagram of a lens in a dynamic laser speckle projection device provided by the present invention; FIG. Figure 6 As shown, the lens includes a voice coil motor 601, a convex lens 602, a first concave lens 603 and a second concave lens 604; wherein:

[0057] The voice coil motor 601 drives at least one of the convex lens 602 , the first concave lens 603 , and the second concave lens 604 to move, so as to adjust the distance between adjacent lenses and achieve focusing.

[0058] Figure 7 FIG. 1 is a side view of the components arranged on the object carrier in the dynamic laser speckle projection device provided by the present invention. Figure 7As shown, the carrier plate 401 is a carrier connecting the electric pan / tilt head 400 and other modules. The laser emitter 100 , the rotating diffraction module 200 , and the lens 300 are all assembled on the carrier plate 401 .

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A dynamic laser speckle projection device, characterized in that: It includes a laser transmitter, a rotating diffraction module, a lens, a loading plate and an electric pan / tilt head; wherein: The laser emitter is used to emit a laser beam; The carrier plate is used to connect the laser emitter, the rotation diffraction module and the lens; the laser emitter, the rotation diffraction module and the lens are sequentially arranged in the optical path direction of the laser beam; The rotating diffraction module includes an optical diffraction device and a rotating motor; the optical diffraction device is used to diffract the laser beam to form a speckle pattern; the optical diffraction device is disposed on a motor shaft of the rotating motor; the rotating motor drives the optical diffraction device to rotate when rotating at an adjustable first speed; each laser beam forms a different speckle pattern after passing through the rotating optical diffraction device; The lens is used to output a speckle coded pattern with adjustable speckle density, spot size and area size after scaling and / or focusing the speckle pattern; The electric pan-tilt head is connected to the loading plate and includes a pan-tilt head base, a pan-tilt head bracket, a first servo, a second servo, and a loading plate; wherein: the first servo drives the laser emitter, the rotating diffraction module, and the lens to rotate in the x-axis direction; the second servo drives the laser emitter, the rotating diffraction module, and the lens to rotate in the y-axis direction.

2. The dynamic laser speckle projection device according to claim 1, characterized in that: The optical path direction of the laser beam is parallel to the rotation axis of the optical diffraction element.

3. The dynamic laser speckle projection device according to claim 1, characterized in that: The distances between the laser emitter, the rotating diffraction module, the lens and the electric pan-tilt platform are adjustable.

4. The dynamic laser speckle projection device according to claim 1, characterized in that: The laser emitter emits a laser beam based on an adjustable first frequency.

5. The dynamic laser speckle projection device according to claim 4, characterized in that: The trigger signal of the laser transmitter is turned on and off according to a preset frequency.

6. The dynamic laser speckle projection device according to claim 5, characterized in that: The duty cycle of the trigger signal may be scalable.

7. The dynamic laser speckle projection device according to claim 1, characterized in that: The laser emitter includes any one of the following: a single semiconductor laser LD; multiple groups of LDs; a vertical cavity surface emitting laser VCSEL.

8. The dynamic laser speckle projection device according to claim 1, characterized in that: The lens includes a voice coil motor, a convex lens, a first concave lens and a second concave lens; wherein: The voice coil motor drives at least one of the convex lens, the first concave lens, and the second concave lens to move, so as to adjust the distance between adjacent lenses.

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