CN110764254A - Compileable Structured Light Projection System - Google Patents

Abstract

The invention discloses a compilable structured light projection system, which comprises an image compiling unit, a control center, a light source, a MEMS micromirror, a feedback unit and other devices. The image compiling unit is used to compile the pattern information of the structured light to be projected according to the input compiling language; the control center is used to control the light source to emit light to the MEMS micromirror, and use the MEMS micromirror to project the scanning beam to the surface of the object to be measured. The generated pattern information controls the MEMS micromirror to rotate to form a preset structured light pattern; the feedback unit is used to obtain the rotation information of the MEMS micromirror, calculate and obtain the position information of the scanning beam projected on the object to be measured, and feed it back to the control center. As a result, the system can freely program each pixel, and can project multiple different types of high-resolution structured light patterns. The system also has the advantages of simple structure, low power consumption, high utilization of light, and strong versatility. The advantages.

Description

Compileable Structured Light Projection System

technical field

The present invention relates to the technical field of structured light, in particular to a structured light projection system for three-dimensional information of an object.

Background technique

Structured light is a pattern composed of points or lines with specific characteristic information, such as grayscale information, color information, spatial position information, etc. By demodulating these information, three-dimensional information of an object can be obtained, which is structured light technology. The principle is to project a specific coded light, namely structured light, to the object to be measured. The flatness of the object surface profile will cause the coded light to deform. At this time, the deformation pattern formed by the coded light is collected by a 3D camera, and then the corresponding deformation pattern is calculated. Displacement, distortion and other information, so as to calculate the depth information of the object and realize the acquisition of three-dimensional information of the object. Structured light technology is widely used in various occasions, such as face recognition, industrial 3D detection, etc.

In the prior art, the following two schemes are generally adopted to obtain the three-dimensional information of an object by using the structured light technology:

1. DOE (optical diffractive element) structured light: The use of optical diffractive elements to generate structured light is a common face recognition solution in mobile phones. The principle is to use VCESL (vertical cavity surface laser) and DOE to project a large number of lattice distribution patterns. The beam emitted by the laser light source is incident on the diffuser to form scattered light. The scattered light passes through the collimating element and then enters the optical diffraction element. After the laser passes through the optical diffraction element, tens of thousands of speckle patterns are diffracted. When the speckle pattern is incident on the face, the pattern reflected by the face back to the detector will carry the three-dimensional information of the face, and then the information of the face can be obtained through a certain algorithm. Among them, the speckle pattern is determined by a specially designed optical diffraction element, which is a large number of lattice distribution patterns. For example, the Face ID in Apple's mobile phone projects a pattern of 30,000 dots.

2. Encoded structured light based on Mask (mask): The working principle is: Vcsel laser (vertical cavity surface emitting laser) uniformly illuminates the mask, and tens of thousands of light and dark patterns are formed by the mask, and then projected through the projection lens, The projection process needs to consider the influence of distortion, and the power consumption is large.

However, no matter which of the above solutions is adopted, the optical diffractive element and the irradiation mask can only correspond to a specific pattern of structured light. If other patterns of structured light are required, the optical diffraction of the desired pattern must be redesigned Components/irradiation masks and replacements are inconvenient and less efficient.

SUMMARY OF THE INVENTION

In view of this, in order to solve the above problems, the present invention adopts the following technical solutions:

A compliable structured light projection system, comprising an image compiling unit, a control center, a light source, a MEMS micromirror and a feedback unit,

Wherein, the image compiling unit is used for compiling the pattern information of the structured light to be projected according to the input compiling language; the control center is used for controlling the light source to emit light to the MEMS micromirror, so that the MEMS micromirror emits light. Project a scanning beam to the surface of the object to be tested, and control the MEMS micromirror to rotate according to the generated pattern information to form a preset structured light pattern; the feedback unit is used to obtain the rotation information of the MEMS micromirror, calculate The position information of the scanning beam projected on the object to be tested is obtained and fed back to the control center.

Preferably, the structured light pattern includes a two-dimensional matrix structured light pattern, the two-dimensional matrix structured light pattern includes a plurality of pattern subunits, and the pattern information includes an image grayscale corresponding to each of the pattern subunits , color information, and the size of the entire image.

Preferably, the compliable structured light projection system includes a storage unit for storing the structured light pattern information compiled by the image compiling unit for the control center to call.

Preferably, an angle sensor or an optical sensor is provided on the MEMS micromirror, and the feedback unit acquires the rotation information of the MEMS micromirror through the angle sensor or the optical sensor.

Preferably, the structured light projection system further includes a shaping lens for optical shaping, and the light emitted by the light source passes through the shaping lens and then goes toward the MEMS micromirror.

Preferably, the light source is a laser.

Preferably, the light source is an infrared laser or an RGB three-color laser.

Preferably, the structured light projection system further includes a reflector, and the light emitted by the light source passes through the shaping lens and is reflected by the reflector before being directed toward the MEMS micromirror.

The compilable structured light projection system provided by the present invention is based on the MEMS micromirror, and the structured light pattern is programmed through the image compiling unit, and the control center controls the light source and the MEMS micromirror according to the pattern information to realize the projection of the specified structured light pattern. Compared with the existing technology, different types of high-resolution structured light patterns can be projected without replacing specific devices, which improves the work efficiency, and has the advantages of reducing structural complexity, high utilization of light and relatively low power consumption. low advantage.

Description of drawings

1 is a schematic structural diagram of a compilable structured light projection system provided by the present invention;

FIG. 2 is an example diagram of a usage flow of the compliable structured light projection system.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the invention shown in the drawings and described with reference to the drawings are merely exemplary and the invention is not limited to these embodiments.

Here, it should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only the structures and/or processing steps closely related to the solution according to the present invention are shown in the drawings, and the relationship is omitted. Not much other details.

Referring to FIG. 1 , an embodiment of the present invention provides a compliable structured light projection system. The compliable structured light projection system includes an image compiling unit 1 , a control center 2 , a light source 3 , a MEMS (Micro-Electro- Mechanical System, micro-electromechanical system) micro mirror 4 and feedback unit 5.

Wherein, as shown in FIG. 2 , the image compiling unit 1 is used to compile the pattern information of the structured light to be projected according to the input compiling language; the control center 2 is used to control the light source 3 to the MEMS micromirror 4. Emit light, project a scanning beam to the surface of the object to be measured with the MEMS micromirror 4, and control the MEMS micromirror 4 to rotate according to the generated pattern information to form a preset structured light pattern; the feedback unit 5 It is used to obtain the rotation information of the MEMS micromirror 4 , calculate and obtain the position information of the scanning beam projected on the object to be measured, and feed it back to the control center 2 .

The compilable structured light projection system provided by the present invention utilizes the image compiling unit 1 to realize the compiling of the structured light pattern, whereby the control center 2 can control the light source based on the MEMS micromirror 4 to the surface of the object to be measured according to the pattern information Project the scanning beam to form the desired structured light pattern, the user can freely select the structured light pattern according to the needs, the projected structured light pattern has high resolution, the compliable structured light projection system can project a variety of structured light patterns, such as At the same time, it projects point structured light and line structured light, which is suitable for a variety of application scenarios and has strong versatility. In particular, compared with the optical diffraction element structured light scheme and the mask-based coded structured light scheme in the prior art, there is no need to replace or redesign specific devices, which is more convenient and helps to improve work efficiency. Moreover, in the optical diffraction element structured light scheme, the device performance will be affected by temperature, and the optical diffraction element will produce 0-order bright spots. Additional light source elements need to be added inside the system to eliminate the 0-order bright spots, which increases the complexity of the system. The efficiency is low; while the mask-based coded structured light scheme is mainly used to improve the 3D restoration speed, which cannot be applied to high-precision 3D restoration. The compliable structured light projection system provided by the present invention can avoid these problems.

Because the above-mentioned compliable structured light projection system has the characteristics of free programming, it can perform grayscale correction and amplitude change on each pixel on the structured light pattern one by one, for example, for the speckle structured light, A two-dimensional matrix structured light pattern such as coded structured light, the two-dimensional matrix structured light pattern includes a plurality of pattern subunits, and the pattern information includes image grayscale, color information and integer information corresponding to each of the pattern subunits. The size of an image, the image compiling unit 1 provides a software compiling window on the supporting operating system, the user can use a simple programming language to compile each pattern subunit, and set the image grayscale ( For example, 0 to 255) and color information, so that the compliable structured light projection system has a very high degree of freedom, which can reduce or even avoid external factors such as reflection on the surface of the object to be measured or a 3D camera that collects structured light images. This causes the problem of uneven light intensity in the 3D information obtained later and the image for 3D restoration.

Specifically, as shown in FIG. 2 , the image formed on the surface of the object to be measured is collected by the three-dimensional camera and processed to generate the three-dimensional information of the object to be measured. There are problems such as uneven distribution of light intensity. With the feature that the above-mentioned image compiling unit 1 can compile each pattern sub-unit, when using the compliable structured light projection system, the light intensity variation area can be corrected, for example, according to The degree of correction that needs to be corrected adds a correction factor to the pattern information corresponding to each pixel on the image, and adjusts the driving current of a light source such as a laser accordingly to make the light intensity distribution uniform. Of course, the control center 2 can also automatically adjust according to the information fed back by the feedback unit 5 by designing a program. In addition, since the MEMS micromirror 4 moves slowly when scanning the left and right sides of the image, the scanning beam stays on the two sides for a long time. When correcting the light intensity of the two sides, it is possible to add or reduce the light intensity there. Laser drive time. When the driving time is increased, the image brightness can be improved due to the integral effect of the 3D camera.

Further, as shown in FIG. 2 , the compliable structured light projection system includes a storage unit 6 for storing the pattern information of the structured light compiled by the image compiling unit 1 for the control Center 2 calls. The compilable structured light projection system can use the storage unit 6 to store each compiled structured light pattern, and the user names the compiled structured light pattern through the operating system software and stores it in the system, which can be freely followed later. Call the stored structured light pattern. For example, some structured light technologies require the combined projection of multiple structured light patterns to obtain the three-dimensional information of the object. At this time, multiple compiled structured light patterns can be called from the storage unit 6, and the corresponding The time interval and sequence of projections between different structured light patterns can complete such three-dimensional information acquisition tasks.

The MEMS micromirror 4 can rotate in two mutually perpendicular directions, namely: 1. Rotate at a relatively fast rotational speed in the lateral direction, which is defined as the fast axis, and 2. Rotate at a relatively slow rotational speed in the longitudinal direction. , the axis is defined as the slow axis. Under the control of the control center 2, the MEMS micromirror 4 rotates on the fast axis and the slow axis respectively, so that the scanning light is reflected by the MEMS micromirror 4 and then scanned in the far field. Forms structured light patterns such as grating shapes or Lissajous shapes. Therefore, in this embodiment, the MEMS micromirror 4 is provided with an angle sensor or an optical sensor. Generally, the angle sensor is integrated in the MEMS micromirror, and the optical sensor can also be embedded outside the system instead of The integrated angle sensor, the feedback unit 5 can acquire the rotation information of the MEMS micromirror 4 in real time through the angle sensor or the optical sensor, specifically including the rotation angle of the MEMS micromirror 4, and due to The MEMS micromirror 4 rotates along the fast axis to resonate, and its feedback signal is a sinusoidal signal. The feedback unit 5 can process the feedback signal to obtain the lateral position of the spot scanning. Similarly, the longitudinal position of the spot scanning can also be obtained according to the feedback signal of the slow axis; when the slow axis is forced to drive, its spot position information is determined by the driving signal, so that the scanning beam can be projected on the to-be-measured by obtaining the scanning beam. The position information on the object is fed back to the control center 2 .

Further, the structured light projection system further includes a shaping lens 7 for optical shaping, and the light emitted by the light source passes through the shaping lens 7 and then goes towards the MEMS micromirror 4 . The shaping lens 7 can shape the light beam into the required spot size and corresponding divergence angle. Exemplarily, the light source 3 is a laser. Further, the light source 3 can be an infrared laser or an RGB three-color laser. The type of the light source 3 can be specifically selected according to actual needs. The laser light emitted by the laser can be collimated into a beam with a smaller diameter and a smaller divergence angle through the above-mentioned shaping lens 7. For example, after the laser emitted by a single-mode laser is collimated to a diameter of 1mm, its divergence angle is less than 1mrad, which is within the range of 1m. The inner spot size remains unchanged. Using a laser as the light source 3 is also beneficial for measuring objects whose surface depth varies greatly and objects in different distance ranges.

Exemplarily, the laser driver chip in the compliable structured light projection system can select a device capable of high-frequency modulation of the laser, such as an ISL58315 high-speed laser diode driver, whose gray level can be from 0 to 1023. For a speckle-like structured light pattern, the image only needs to be distinguished by light and dark, and high-frequency switching devices such as triodes and MOS tubes can be used to drive the laser, which is conducive to reducing the system cost as much as possible while meeting the requirements. power consumption.

In addition, in order to test the three-dimensional information of objects at different positions, in order to ensure that the structured light pattern can perfectly illuminate the object, based on the above-mentioned compliable structured light projection system, the maximum scan angle can be normalized, and the user can customize it according to the actual application. Perform conversion, readjust the pattern scanning angle, and match the appropriate structured light pattern size.

Further, the structured light projection system further includes a reflector 8 , and the light emitted by the light source 3 passes through the collimating lens 7 and is reflected by the reflector 8 before being emitted to the MEMS micromirror 4 . The reflector 8 can be used to adjust the optical path, so as to conveniently set the spatial distribution of each component inside the system.

To sum up, the compliable structured light projection system provided by the embodiments of the present invention builds a compliable structured light projection system based on the MEMS micromirror 4, which can realize free programming of each pixel in the structured light pattern, which is convenient for Compared with the conventional scheme of the prior art, the system is simpler, the power consumption is lower, the utilization rate of light is high, and the system is widely used. Strong sex.

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements, It also includes other elements not expressly listed or inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above are only specific embodiments of the present application. It should be pointed out that for those skilled in the art, without departing from the principles of the present application, several improvements and modifications can also be made. It should be regarded as the protection scope of this application.

Claims (8)

1. a compileable structured light projection system, is characterized in that, comprises image compilation unit, control center, light source, MEMS micromirror and feedback unit, Wherein, the image compiling unit is configured to compile the pattern information of the structured light to be projected according to the input compiling language; The control center is used to control the light source to emit light to the MEMS micromirror, project a scanning beam to the surface of the object to be measured by the MEMS micromirror, and control the MEMS micromirror to rotate according to the generated pattern information, forming a preset structured light pattern; The feedback unit is used to obtain the rotation information of the MEMS micromirror, calculate and obtain the position information of the scanning beam projected on the object to be measured, and feed it back to the control center. 2 . The compliable structured light projection system according to claim 1 , wherein the structured light pattern comprises a two-dimensional matrix structured light pattern, and the two-dimensional matrix structured light pattern comprises a plurality of pattern subunits. 3 . , the pattern information includes image grayscale, color information and the size of the entire image corresponding to each of the pattern subunits. 3 . The compliable structured light projection system according to claim 1 , wherein the compliable structured light projection system comprises a storage unit for storing the structured light compiled by the image compiling unit. 4 . pattern information for the control center to call. 4 . The compliable structured light projection system according to claim 1 , wherein an angle sensor or an optical sensor is provided on the MEMS micromirror, and the feedback unit is obtained by the angle sensor or the optical sensor. 5 . Rotation information of the MEMS micromirror. 5 . The compliable structured light projection system according to claim 1 , wherein the structured light projection system further comprises a shaping lens for optical shaping, and the light emitted by the light source passes through the shaping lens and is emitted backward. 6 . to the MEMS micromirror. 6. The compliable structured light projection system according to claim 1, wherein the light source is a laser. 7 . The compliable structured light projection system according to claim 6 , wherein the light source is an infrared laser or an RGB three-color light laser. 8 . 8 . The composable structured light projection system according to claim 5 , wherein the structured light projection system further comprises a reflection mirror, and the light emitted by the light source passes through the shaping lens and then passes through the reflection mirror. 9 . The reflection is then directed towards the MEMS micromirror.

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