3D radiation-resistant imaging system

Abstract

The invention discloses a 3D radiation-resistant imaging system, and belongs to the technical field of measurement sensing. The system comprises a mechanical grating projection module (1) composed of an active light source (101) and a mechanical grating (104), a 2D radiation-resistant camera (2), a power supply (3), a computer (4), a radiator (102) and the like. All parts of the mechanical grating projection module (1) are made of radiation-resistant materials and do not contain radiation-sensitive elements such as optical lenses, micro-mirrors and optical glass. During working, the power supply (3) supplies power to the system, light emitted by the active light source (101) passes through the mechanical grating (104), and a preset coding pattern is projected to a measured object (5); the 2D radiation-resistant camera (2) collects a pattern deformed due to the surface contour of the object from another angle; the computer (4) processes the collected image and calculates the three-dimensional point cloud coordinates of the surface of the object through triangulation and other algorithms. The system is high in radiation resistance level and low in cost, high-density point cloud can be obtained, and the system has wide application prospects in the special fields of nuclear radiation, nuclear power and the like.

Description

Technical Field

[0001] This invention relates to the field of measurement and sensing technology, and in particular to a 3D radiation-resistant imaging system. Background Technology

[0002] In nuclear-related industries such as nuclear power plant operation and maintenance, spent fuel reprocessing, nuclear facility decommissioning, radioactive waste disposal, and uranium mining and exploration, the presence of strong radiation environments creates an urgent need for automated and intelligent equipment such as robots. 3D vision systems are crucial for environmental perception and autonomous navigation; therefore, radiation-resistant 3D cameras are a core component of specialized equipment for radiation environments.

[0003] Currently, active 3D vision technologies (such as structured light, multi-line laser, and time-of-flight (TOF)) are the mainstream technologies for industrial-grade 3D cameras. However, the core components in existing commercial 3D cameras are highly sensitive to radiation. For example, laser diodes and MEMS micromirrors are typically manufactured using standard semiconductor processes. Under strong radiation, gamma rays and neutrons can introduce displacement and ionization damage into their silicon lattices, leading to a surge in dark current, gain drift, and even functional failure. Simultaneously, materials such as precision optical glass, microlens arrays, and optical adhesives relied upon by structured light projection and TOF cameras undergo "irradiation coloring" under irradiation, becoming black, brittle, cracked, or releasing gas, thus losing their original optical properties and consistency. The performance instability of these commonly used industrial components under strong radiation environments significantly increases the difficulty and manufacturing cost of radiation-resistant 3D imaging systems, resulting in almost no commercially available 3D camera products capable of withstanding strong radiation (e.g., dose rates greater than 10 kGy / h and cumulative doses greater than 1 mgy). Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a 3D radiation-resistant imaging system with simple structure, low cost and excellent radiation resistance, so as to solve the problem of three-dimensional imaging in strong radiation environment.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A 3D radiation-resistant imaging system includes: a mechanical grating projection module, a 2D radiation-resistant camera, a power supply, a computer, and a measurement platform.

[0007] The mechanical grating projection module is used to project structured light patterns with coded information onto the surface of the object being measured. The module consists of an active light source, a mechanical grating, a heat sink, and a support. To ensure radiation resistance, this module eliminates radiation-sensitive components and materials commonly used in traditional structured light projection, such as lasers, MEMS micromirrors, optical lenses, microstructured glass, and adhesives.

[0008] The 2D radiation-resistant camera is fixed on the measurement platform and is used to capture the coded pattern on the surface of the object being measured, which is deformed due to the object's outline, and to transmit the acquired image information to the computer.

[0009] The power source provides power to the mechanical grating projection module, the 2D radiation-resistant camera, the computer, and other components that require electrical energy.

[0010] The computer is connected to the mechanical grating projection module and the 2D radiation-resistant camera. The computer controls the projection timing and frequency of the active light source, as well as the acquisition timing and frequency of the 2D radiation-resistant camera, and processes and calculates the deformed pattern images acquired by the camera to finally calculate the three-dimensional point cloud coordinates of the object under test.

[0011] Furthermore, the active light source is preferably an LED light source with a high radiation tolerance rating. LED light sources have better radiation tolerance compared to laser diodes and other similar sources.

[0012] Furthermore, the mechanical grating is made of radiation-resistant metal material (such as stainless steel) through precision machining (such as laser cutting and etching), and has a preset coded pattern processed on it, such as multi-line, speckle, or stripe patterns. Light emitted from the active light source passes through the mechanical grating and projects the coded pattern outward.

[0013] Furthermore, the 2D radiation-resistant camera can be a commercially available radiation-resistant camera product, whose core imaging chip and circuitry have undergone special reinforcement or shielding design, enabling it to work stably in strong radiation environments.

[0014] Furthermore, the projection of the active light source is controlled by a computer and synchronized with the acquisition by the 2D radiation-resistant camera. For example, the projection / acquisition frequency is controlled to be no less than 10Hz to meet the frame rate requirements of real-time or near-real-time measurements.

[0015] The working principle of this invention is as follows: First, the relative pose relationship between the mechanical grating projection module and the 2D radiation-resistant camera is precisely calibrated using camera calibration methods such as the Zhang Zhengyou calibration method. During measurement, an active light source emits light, which passes through the mechanical grating and projects the coded pattern onto the object being measured. Due to the three-dimensional contour of the object's surface, the projected pattern will deform. The 2D radiation-resistant camera captures this deformed pattern from another angle and transmits the image to a computer. Based on the pre-calibrated intrinsic and extrinsic parameters and relative pose, the computer uses the principle of triangulation to calculate the spatial three-dimensional coordinates (X, Y, Z) corresponding to each pixel in the image, thereby reconstructing a high-density three-dimensional point cloud of the surface of the object being measured.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. High radiation resistance: The core projection components (active light source and mechanical grating) of this system are made of radiation-resistant elements and materials, which fundamentally avoids the use of radiation-sensitive components (such as lasers, MEMS, and optical glass) in traditional 3D cameras, and can adapt to radiation environments with higher dose rates and cumulative doses. 2. Low cost: The mechanical grating is made of common metal materials such as stainless steel, making its cost far lower than that of precision micro-optical components and MEMS micromirrors. The active light source uses radiation-resistant LEDs, which are also less expensive than specially customized radiation-resistant lasers. This significantly reduces the research and development and manufacturing costs of the entire system. 3. Capable of acquiring high-density point clouds: By designing complex coding patterns (such as high-density linear arrays and speckle patterns) on mechanical gratings and combining them with a high-resolution 2D radiation-resistant camera, the system can acquire hundreds of thousands or even millions of three-dimensional data points in a single shot, meeting the needs of high-precision measurement. 4. Broad application prospects: With its advantages of high radiation resistance and low cost, this invention has great application potential in the fields of nuclear power plant operation and maintenance, nuclear waste treatment, and nuclear facility decommissioning. It can provide key visual perception capabilities for tasks such as autonomous robot operation, equipment status monitoring, and environmental modeling in radiation environments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a 3D radiation-resistant imaging system according to the present invention.

[0018] Figure 2 This is a schematic diagram of the mechanical grating projection module in this invention.

[0019] Figure 3 This is a schematic diagram illustrating the specific workflow of a 3D radiation-resistant imaging system according to the present invention.

[0020] Explanation of reference numerals in the attached figures: 1-Mechanical grating projection module; 101-Active light source; 102-Heat sink; 103-Bracket; 104-Mechanical grating; 2-2D radiation-resistant camera; 3-Power supply; 4-Computer; 5-Object under test; 6-Measuring platform. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] Example 1

[0023] See Figure 1 This embodiment provides a 3D radiation-resistant imaging system, see [link to documentation]. Figure 1 The system includes a mechanical grating projection module (1), a 2D radiation-resistant camera (2), a power supply (3), a computer (4), the object under test (5), and a measurement platform (6). See also... Figure 2 The mechanical grating projection module includes an active light source (101), a heat sink (102), a bracket (103), and a mechanical grating (104).

[0024] The power supply (3) is connected to the mechanical grating projection module (1), the 2D radiation-resistant camera (2), and the computer (4) to provide them with energy. The computer (4) is connected to the mechanical grating projection module (1) and the 2D radiation-resistant camera (2) to provide control signals. The images acquired by the 2D radiation-resistant camera (2) are sent to the computer (4) for processing and calculation. The mechanical grating projection module (1) and the 2D radiation-resistant camera (2) are fixedly installed on the measurement platform (6).

[0025] See Figure 2 In the mechanical grating projection module (1) of the system, the active light source (101) projects a pattern with coded information through the mechanical grating (104), preferably such as multi-line, speckle, or stripe patterns. The coded pattern is projected onto the object under test (5) and deforms.

[0026] The 2D radiation-resistant camera (2), preferably a commercially available 2D radiation-resistant camera, can capture information about the deformed patterns projected onto the surface of an object.

[0027] The computer (4) is able to control the time and frequency of the active light source (101) projection, as well as the acquisition time and frequency of the 2D radiation-resistant camera (2).

[0028] The computer (4) is able to perform image processing and three-dimensional point cloud computing based on the image information collected by the 2D radiation-resistant camera (2).

[0029] Example 2

[0030] The specific workflow of the system is as follows, see below. Figure 3 :

[0031] Step 1: System Calibration. Before measurement, the system is placed in the calibration field using a high-precision checkerboard calibration plate. The internal parameters (such as focal length, principal point coordinates, and distortion coefficients) and external parameters of the 2D radiation-resistant camera (2) are calculated using the Zhang Zhengyou calibration method. At the same time, the mechanical grating projection module (1) is equivalent to a "reverse camera," and its virtual internal parameters and external parameters relative to the 2D radiation-resistant camera (2) (i.e., rotation matrix R and translation vector T) are calibrated. After calibration, the relative pose relationship between the camera and the projection module is accurately determined and stored in the computer (4).

[0032] Step 2: Image Acquisition. The system is aimed at the object under test (5). The computer (4) sends a synchronous trigger signal to control the active light source (101) and the 2D radiation-resistant camera (2). For example, a 50ms cycle is set, where for the first 10ms, the active light source (101) is powered on and emits light, while the 2D radiation-resistant camera (2) performs exposure acquisition; for the next 40ms, the active light source (101) is powered off, and the camera completes data readout. This cycle repeats, achieving a 20Hz acquisition frame rate. The light emitted by the active light source (101) passes through the mechanical grating (104), projecting a 50-line structured light pattern onto the surface of the object under test (5). Due to the uneven surface of the object, the originally straight lines become curved stripes from the camera's perspective. The 2D radiation-resistant camera (2) captures this image with deformed stripes.

[0033] Step 3: 3D point cloud computing. The 2D radiation-resistant camera (2) transmits the acquired images to the computer (4) in real time. The software algorithm of the computer (4) first preprocesses the image, such as denoising and binarization, and then extracts the center line of the deformed stripes. According to the calibrated system parameters, for any pixel on the stripe, the unique three-dimensional coordinates (X, Y, Z) of the pixel in space can be calculated using the triangulation method. By traversing all pixels on all stripes, a frame containing approximately 737,000 data points (assuming an average of 1,500 effective pixels per line, 1,500 * 50 * 0.98 ≈ 737,000) can be obtained. Since the acquisition frame rate is 20Hz, the system can generate approximately 14.74 million point cloud data per second, which is sufficient to meet the requirements of high-density three-dimensional measurement of objects under strong radiation conditions.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. For example, the pattern on the mechanical grating (104) can be replaced with a random speckle pattern to adapt to the measurement of different textured surfaces; the algorithm of the computer (4) can also use the phase shift method or Gray code method (requiring multiple frames of images) to obtain higher precision point clouds, all of which fall within the scope of protection of the present invention.

Claims

1. A 3D radiation tolerant imaging system characterized by: The system comprises a mechanical grating projection module (1), a 2D radiation-resistant camera (2), a power supply (3), a computer (4), a measured object (5), and a measurement platform (6); the mechanical grating projection module comprises an active light source (101), a heat sink (102), a bracket (103), and a mechanical grating (104); The power supply (3) is connected with the mechanical grating projection module (1), the 2D radiation-resistant camera (2), and the computer (4) to provide energy for them; The computer (4) is connected with the mechanical grating projection module (1) and the 2D radiation-resistant camera (2) to provide control signals and send the images collected by the 2D radiation-resistant camera (2) to the computer (4) for processing and calculation; The mechanical grating projection module (1) and the 2D radiation-resistant camera (2) are fixedly installed on the measurement platform (6); The active light source (101) projects a pattern coding pattern with coding information on the measured object (5) through the mechanical grating (104) to cause deformation; The 2D radiation-resistant camera (2) can shoot the deformed pattern information projected on the surface of the object; The computer (4) can control the projection time and frequency of the active light source (101) and the shooting and collection time and frequency of the 2D radiation-resistant camera (2); The computer (4) can perform image processing and three-dimensional point cloud calculation based on the image information collected by the 2D radiation-resistant camera (2).

2. The 3D radiation tolerant imaging system of claim 1, wherein, The active light source (101) adopts a radiation-resistant light source such as a radiation-resistant LED, and discards radiation-sensitive light sources such as lasers and MEME micro-mirrors to meet the radiation resistance requirements of the light source.

3. The 3D radiation tolerant imaging system of claim 1, wherein, The active light source projection part is free of radiation-sensitive elements or materials such as optical lenses, microstructures, and adhesives; the mechanical grating (104) is made of a radiation-resistant material such as stainless steel.

4. The 3D radiation tolerant imaging system of claim 1, wherein, The mechanical grating (104) is processed with a coding pattern such as a multi-line, speckle, or stripe; the active light source (101) and the mechanical grating (104) form the mechanical grating projection module (1); the light emitted by the active light source (101) is projected onto the object through the mechanical grating (104) to realize coding of the depth information of the object.

5. The 3D radiation tolerant imaging system of claim 1, wherein, The 2D radiation-resistant camera (2) adopts a commercial 2D radiation-resistant camera on the market to collect the pattern projected on the object by the mechanical grating projection module (1).

6. The 3D radiation tolerant imaging system of claim 1, wherein, The computer can control the projection time and frequency of the active light source (101) and the shooting and collection time and frequency of the 2D radiation-resistant camera (2); preferably, the projection of the active light source (101) and the collection of the 2D radiation-resistant camera (2) are performed synchronously, and the projection / collection frequency should meet the test frame rate requirements, preferably not less than 10 hz.

7. The 3D radiation tolerant imaging system of claim 1, wherein, The computer (4) can perform image processing and three-dimensional point cloud calculation based on the image information collected by the 2D radiation-resistant camera (2) to obtain the 3D information of the measured object.

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