Laser-fused dual-wavelength all-pose visual sensor

Abstract

The utility model discloses a laser-fused dual-wavelength all-pose visual sensor and a method. The sensor adopts the camera, the lens and the LED light source, and can realize the measurement of up-down and left-right translation and rotation angle of a target through the reflecting plate. Meanwhile, four lasers parallel to the optical axis of the parallel lens are adopted to form upper, lower, left and right laser triangulation ranging units, and measurement of the target distance, up-and-down pitching and left-and-right swing angles can be achieved. Therefore, non-contact high-precision detection of the three-dimensional position and the three-dimensional attitude of the target can be realized. In addition, the wavelengths of the laser and the LED light source are red light and blue light respectively, the camera is a color camera, laser triangulation ranging and monocular vision measurement can be achieved at the same time through RGB components of one image, and therefore 6D all-pose synchronous detection is achieved.

Description

Technical Field

[0001] This utility model relates to a pose sensor and method, specifically, a dual-wavelength full-pose visual sensor that integrates laser. Background Technology

[0002] Target position and attitude detection is a common inspection requirement in many sectors of the national economy. Examples include docking of space mechanisms, positioning of robot end effectors, random grasping by robots, and intelligent pressing.

[0003] Conventional position and attitude detection are performed separately, i.e., detecting the target's 3D position and 3D attitude separately. There are many methods for 3D position detection, such as using laser triangulation sensors, laser trackers, coordinate measuring machines, and total stations. Methods for 3D attitude detection are fewer, such as photoelectric collimation and multi-point reflector methods. Some scholars in Tianjin have proposed a deep learning-based attitude detection method, but it is still in the laboratory research stage. In particular, there is currently a lack of means and methods, both domestically and internationally, to directly detect the 6D full pose parameters of a target's 3D position and 3D attitude.

[0004] Therefore, there is an urgent need for a high-precision, integrated 6D full pose parameter detection method to meet the application needs of multiple scenarios. Summary of the Invention

[0005] This invention addresses the current lack of 6D pose detection methods by proposing a dual-wavelength full-pose visual sensor integrating laser technology. This visual sensor employs a camera, lens, and LED light source. Through a reflector, it can measure three degrees of freedom: vertical and horizontal translation and rotation of the target. Simultaneously, four lasers parallel to the optical axes of the camera and lens form four laser triangulation units, enabling the measurement of three degrees of freedom: target distance, vertical pitch, and horizontal sway. Thus, non-contact, high-precision detection of six degrees of freedom—three-dimensional position and three-dimensional pose—can be achieved. Furthermore, the laser and LED light sources use red and blue light wavelengths respectively, and the camera is a color camera, allowing simultaneous laser triangulation and monocular vision measurement using the RGB components of a single image, thereby achieving synchronous 6D full-pose detection.

[0006] This utility model is achieved through the following technical solution:

[0007] The unique feature of this invention's dual-wavelength full-pose visual sensor based on fused laser technology is that the sensor comprises a visual probe and a reflector. The visual probe includes a camera, lens, laser, LED light source, filter, processing circuitry, and housing.

[0008] The camera is an industrial-grade camera responsible for acquiring images of the reflector; the camera is a color camera capable of extracting RGB components.

[0009] The lens is an industrial-grade high-resolution lens, responsible for imaging the image of the reflector onto the image plane of the camera;

[0010] The lasers are industrial-grade semiconductor lasers, four in total, located around the lens in a 90° arrangement, with the laser beams emitted by the four lasers parallel to the optical axis of the camera and lens; the laser wavelengths are either red or blue.

[0011] The LED light source consists of multiple LEDs, which are evenly arranged around the lens and spaced apart from the laser. The center wavelength of the LED light source is either red or blue, but it must be different from the wavelength of the laser.

[0012] The filter is a dual-bandpass narrowband filter, the center wavelengths of its two passbands are the same as the center wavelength of the laser and the center wavelength of the anti-LED light source, respectively, and the bandwidth of its two passbands is less than 1 / 4 of the difference between the two wavelengths; the filter is located at the front end of the vision probe and is used to filter out other environmental interference light.

[0013] The processing circuit is a measurement and control circuit based on a high-performance microprocessor. On the one hand, it is responsible for controlling the laser and LED light source, and on the other hand, it is responsible for processing the color image data of the camera, extracting the R component and B component, and obtaining the required 6 pose parameters.

[0014] The outer shell is made of a highly conductive metal material, which is used to support and fix all internal components, and to provide reliable protection and shielding.

[0015] The reflector has a three-layer structure: the middle layer is a substrate with a diffuse reflective surface, ensuring that the laser beams emitted by the four lasers reliably irradiate the substrate; the upper layer is a reflective mark made of retroreflective material, smaller than the substrate, including a central reflective mark with a symmetrical shape located in the center, and four linear reflective marks evenly distributed around the central reflective mark at 90° angles; the lower layer is a strong magnetic plate, one side of which is bonded to the diffuse reflective substrate, and the other side is magnetically fixed to a certain metal plane of the target being measured, ensuring that the reflector moves with the target being measured.

[0016] The working process of this invention's dual-wavelength full-pose vision sensor based on laser fusion is as follows: First, a reflector is attached to a surface of the target object. Then, under the control of the processing circuit, four LED light sources are turned on to illuminate the reflector, and four lasers are simultaneously activated to generate four light spots on the reflector surface. The camera then acquires an image of the reflector area, which is sent to the processing circuit for processing. The G component in the color image is removed, retaining the R and B components. By processing the R and B components of the color image signal respectively, the vertical and horizontal translation and rotation information corresponding to monocular vision, and the distance, vertical pitch, and horizontal sway information corresponding to laser triangulation can be obtained simultaneously—a total of six degrees of freedom parameters, thus yielding position and attitude signals.

[0017] The unique feature of this invention's dual-wavelength full-pose vision sensor with fused laser technology is that the reflective mark in the reflector plate can adopt various combined symmetrical shapes or form an integrated reflective mark.

[0018] This invention proposes a data processing method for a dual-wavelength full-pose visual sensor used in the aforementioned fused laser system. This method can simultaneously obtain measurement results for three directional coordinate values ​​and three rotation axis angle values, totaling six degrees of freedom, as detailed below:

[0019] (1) The processing circuit turns on four LED light sources to illuminate the reflector and turns on four lasers to form four laser spots on the surface of the reflector.

[0020] (2) The camera captures an image that contains both a red or blue laser spot and a reflective marker;

[0021] (3) Remove the G component from the color image and retain the R and B components where the laser spot and reflection mark are located;

[0022] (4) Process the R component (or B component) of the color image to obtain the coordinates of the center points of the four laser spots, and use the pre-stored calibration curve to obtain the four distance values;

[0023] (5) Take the average of the above four distance values ​​as the distance between the visual probe and the reflector;

[0024] (6) Take the difference between the upper and lower distance values ​​of the above four distance values, divide it by the distance between the two laser spots, and then calculate the arctangent to obtain the pitch angle value of the reflector.

[0025] (7) Take the difference between the left and right distance values ​​of the above four distance values, divide it by the distance between the two laser spots, and then calculate the arctangent to obtain the left and right tilt angle values ​​of the reflector.

[0026] (8) Process the B component (or R component) of the color image to obtain the coordinates of the circular reflective mark, and use the pre-stored measurement curve to obtain the coordinate values ​​of the reflector in the up and down and left and right directions.

[0027] (9) Process the B component (or R component) of the color image to obtain the angles between the four straight reflection marks and the upper, lower, left and right coordinate axes, and take the average of the two angles as the rotation angle value of the reflector. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the dual-wavelength all-position vision sensor with fused laser according to this utility model.

[0029] Figure 2 This is a schematic diagram of the layout of the laser and LED light source for the all-position vision sensor of this utility model;

[0030] Figure 3 This is a schematic diagram of the passband of the filter of this utility model;

[0031] Figure 4 This is a schematic diagram of the reflector composition of this utility model;

[0032] Figure 5 A schematic diagram of an image captured by the camera of this utility model;

[0033] Figure 6 A schematic diagram of an image captured by the camera of this utility model;

[0034] Figure 7 This is a schematic diagram illustrating the measurement principle of distance, pitch angle, and yaw angle of this utility model;

[0035] Figure 8 This is a schematic diagram illustrating the principle of translation coordinate and rotation angle measurement of this utility model;

[0036] In the diagram, 1 is the vision probe, 2 is the reflector, 3 is the camera, 4 is the lens, 5 is the laser, 6 is the LED light source, 7 is the filter, 8 is the processing circuit, 9 is the outer casing, 10 is the substrate, 11 is the reflective mark, and 12 is the magnetic plate. Detailed Implementation

[0037] The embodiments of this utility model will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of this utility model and provide detailed implementation methods and specific operation processes. However, the protection scope of this utility model is not limited to the following embodiments.

[0038] The unique feature of this invention's dual-wavelength all-pose visual sensor based on fused laser technology is that the sensor comprises a visual probe 1 and a reflector 2. The visual probe 1 includes a camera 3, a lens 4, a laser 5, an LED light source 6, a filter 7, a processing circuit 8, and a housing 9. Figure 1 As shown, where:

[0039] The camera 3 is an industrial-grade camera responsible for acquiring images of the reflector 2; the camera 1 is a color camera capable of extracting RGB components.

[0040] The lens 4 is an industrial-grade high-resolution lens, responsible for imaging the image of the reflector 2 onto the image plane of the camera 3;

[0041] The laser 5 is an industrial-grade semiconductor laser, consisting of four lasers: 5-1, 5-2, 5-3, and 5-4. These lasers are located around the lens 4, arranged vertically, horizontally, and at 90° intervals. The laser beams emitted by the four lasers 5-1, 5-2, 5-3, and 5-4 are all parallel to the optical axes of the camera 3 and the lens 4. The wavelength of the laser 4 is either red or blue light, for example, 650nm red light can be used.

[0042] Multiple LED light sources 6 are evenly arranged around the lens 4, spaced apart from the laser 5, such as... Figure 2 As shown, there are four LED light sources 6-1, 6-2, 6-3, and 6-4, arranged between four lasers 5-1, 5-2, 5-3, and 5-4; the center wavelength of the LED light source 6 is either red or blue light, but it must be different from the wavelength of the laser 5; for example, if the laser wavelength is 650nm red light, then the LED light source can be 405nm blue-violet light.

[0043] The filter 7 is a dual-bandpass narrowband filter. The center wavelengths of its two passbands should be consistent with the center wavelengths of the laser 5 and the LED light source 6, respectively. The bandwidth of its two passbands is less than 1 / 4 of the difference between the two wavelengths. Figure 3 As shown; for example, for laser 5 with a wavelength of 650nm and LED light source 6 with a wavelength of 405nm, the center wavelengths of the two bandpasses of filter 7 are 650nm and 405nm respectively, and the bandwidth does not exceed 60nm; filter 7 is located at the front end of the sensor and is used to filter out other interfering light.

[0044] The processing circuit 8 is a high-performance microprocessor-based circuit. On the one hand, it is responsible for controlling the laser 5 and the LED light source 6, and on the other hand, it is responsible for processing the image data of the camera 3, extracting the R component and the B component, and finally obtaining the required 6 pose parameters.

[0045] The outer shell 9 is made of a highly conductive metal material, such as aluminum alloy, stainless steel, copper, etc., to support and fix all internal components and provide reliable protection and shielding.

[0046] The reflector 2 described above adopts a three-layer structure, such as... Figure 4 As shown: the middle layer is a substrate 10 with a diffuse reflective surface, ensuring that the laser beams emitted by the four lasers 5-1, 5-2, 5-3, and 5-4 reliably irradiate the substrate 10; the upper layer is a reflective mark 11 made of retroreflective material, smaller than the substrate 10, including a central reflective mark 11-1 with a symmetrical shape located in the center, and four straight reflective marks 11-2 evenly distributed around the central reflective mark at 90° angles; the lower layer is a strong magnetic plate 12, one side of which is bonded to the diffuse reflective substrate 10, and the other side is magnetically fixed to a certain metal plane of the target being measured, ensuring that the reflective plate 2 moves with the target being measured.

[0047] The working process of this invention's dual-wavelength all-position vision sensor based on laser fusion is as follows: Under the control of the processing circuit 8, four LED light sources 6 are first turned on to illuminate the reflector 2, and simultaneously four lasers 5 are turned on to generate four laser spots on the surface of the reflector 2. Then, the camera 3 acquires an image of the area where the reflector 2 is located and sends it to the processing circuit 8 for processing. The G component in the color image is removed, and the R and B components are retained. By processing the R and B components of the color image signal respectively, the vertical and horizontal translation and rotation information corresponding to monocular vision and the distance, vertical and horizontal pitch information corresponding to laser triangulation can be obtained simultaneously, thereby obtaining position and attitude signals and achieving zero-position calibration.

[0048] The special feature of the dual-wavelength full-pose vision sensor with fusion laser of this invention is that the reflective mark 11 in the reflector plate 2 can adopt a variety of combined symmetrical shapes, or can form an integrated reflective mark 11.

[0049] This invention proposes a data processing method for a dual-wavelength full-pose visual sensor used in the aforementioned fused laser system. This method can simultaneously obtain measurement results for three directional coordinate values ​​and three rotation axis angle values, totaling six degrees of freedom, as detailed below:

[0050] (1) The processing circuit 8 turns on four LED light sources 6-1, 6-2, 6-3, and 6-4 to illuminate the reflector 2, and at the same time turns on four lasers 5-1, 5-2, 5-3, and 5-5 to form four laser spots on the surface of the reflector 2d;

[0051] (2) Camera 3 captures an image, such as Figure 5As shown, the image contains red or blue laser spots 13-1, 13-2, 13-3, 13-4 and reflective markers 11-1, 11-2.

[0052] (3) Remove the G component from the color image and retain the R and B components where the laser spot 13 and the reflection mark 11 are located; for example, if the wavelength of the laser 5 is red light, then the laser spot 13 is in the R component; if the wavelength of the LED spot is blue light, then the reflection mark 11 is in the B component.

[0053] (4) Process the R component of the color image to obtain the center point coordinates L1(x1,y1), L2(x2,y2), L3(x3,y3), and L4(x4,y4) of the four laser spots 13-1, 13-2, 13-3, and 13-4, and obtain four distance values ​​Z1, Z2, Z3, and Z4 using the pre-stored calibration curve, as shown. Figure 6 As shown;

[0054] (5) Take the average of the above four distance values ​​Z1, Z2, Z3 and Z4 as the distance Z between the visual probe 1 and the reflector 2, that is, Z = (Z1 + Z2 + Z3 + Z4) / 4;

[0055] (6) Take the difference between the two upper and lower distance values ​​Z1 and Z3 among the above four distance values, divide it by the distance D between the two laser spots 13-1 and 13-3, and then calculate the arctangent. From this, we can obtain the pitch angle value β of the reflector 2, that is, β = arctan[(Z1–Z3) / D];

[0056] (7) Take the difference between the left and right distance values ​​Z2 and Z4 among the above four distance values, divide it by the distance D between the two laser spots 13-2 and 13-4, and then calculate the arctangent. From this, we can obtain the left and right tilt angle value γ of the reflector, that is, γ = arctan[(Z2 –Z4) / D];

[0057] (8) Process the B component of the color image to obtain the coordinates C(xc,yc) of the circular reflective mark 11-1, and use the pre-stored measurement curve to obtain the coordinate values ​​Xc and Yc of the reflector 2 in the up-down and left-right directions, as follows. Figure 7 As shown;

[0058] (9) Process the B component of the color image to obtain the angles α1 and α2 between the four straight reflection marks 11-1 and the XY coordinate axes. Take the average of the two angles α1 and α2 as the rotation angle value α of the reflector 2, that is, α=(α1+α2) / 2.

[0059] Compared with the prior art, the present invention has the following outstanding technical advantages:

[0060] (1) Since the full pose sensor of this utility model uses four parallel laser triangulation to obtain the required distance information, and uses monocular vision and reflection marks to obtain translation position and rotation information, it calculates three coordinate values ​​and three rotation values ​​of the reflector, resulting in a total of six degrees of freedom. It not only has many detection parameters and high measurement accuracy, but also has no impact on the target being measured, and has the best versatility.

[0061] (2) Since the full pose sensor of this utility model uses dual wavelengths to realize multiple detection of 6 parameters, it can simultaneously acquire all 6 parameter information in one image. It is not only fast, but also synchronously processed, which is more reasonable.

Claims

1. A dual-wavelength all-pose vision sensor incorporating laser technology, characterized in that, The sensor consists of a vision probe and a reflector. The vision probe includes a camera, lens, laser, LED light source, filter, processing circuitry, and housing. The camera is an industrial-grade camera responsible for acquiring images of the reflector; the camera is a color camera capable of extracting RGB components. The lens is an industrial-grade high-resolution lens, responsible for imaging the image of the reflector onto the image plane of the camera; The lasers are industrial-grade semiconductor lasers, four in total, located around the lens in a 90° arrangement (up, down, left, right). The laser beams emitted by the four lasers are parallel to the optical axis of the camera and lens. The wavelengths of the lasers are either red or blue. The LED light source is multiple, evenly arranged around the lens, and spaced apart from the laser; the center wavelength of the LED light source is red or blue light, but must be different from the wavelength of the laser. The filter is a dual-bandpass narrowband filter, the center wavelengths of its two passbands should be consistent with the center wavelength of the laser and the center wavelength of the LED light source, respectively, and the bandwidth of its two passbands is less than 1 / 4 of the difference between the two wavelengths; the filter is located at the front end of the sensor and is used to filter out other interfering light. The processing circuit is a high-performance microprocessor-based circuit. On the one hand, it is responsible for controlling the laser and LED light source, and on the other hand, it is responsible for processing the color image data of the camera, extracting the R component and B component, and obtaining the required 6 pose parameters. The outer shell is made of a highly conductive metal material, which is used to support and fix all internal components, and to provide reliable protection and shielding. The reflector has a three-layer structure: the middle layer is a substrate with a diffuse reflective surface, ensuring that the laser beams emitted by the four lasers reliably irradiate the substrate; the upper layer is a reflective mark made of retroreflective material, smaller than the substrate, including a central reflective mark with a symmetrical shape located in the center, and four linear reflective marks evenly distributed around the central reflective mark at 90° angles; the lower layer is a strong magnetic plate, one side of which is bonded to the diffuse reflective substrate, and the other side is magnetically fixed to a certain metal plane of the target being measured, ensuring that the reflector moves with the target being measured.

2. The dual-wavelength all-pose visual sensor with fused laser as described in claim 1, characterized in that, The reflective markings in the reflector can take various combinations of symmetrical shapes, or they can form an integrated reflective marking.

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