An automatic detection device and method for cloud defects inside a crystal

Abstract

The present invention discloses an automatic detection device for cloud defects inside a crystal, comprising a main support, a rotating platform, a dot-matrix laser module, an image acquisition device and a computer system; the rotating platform comprises a rotating platform base and a rotating platform bearing panel; the rotating platform base is fixedly connected to the main support, the dot-matrix laser module is arranged on the upper part of the main support, and is located directly above the rotating platform bearing panel, a point laser light source distribution panel is arranged at the bottom of the dot-matrix laser module, a plurality of point laser light sources are arranged on the point laser light source distribution panel, and each point laser light source is controlled by an independent optical fiber lead-out switch; the image acquisition device is arranged on the side of the rotating platform bearing panel; the computer system is connected to the image acquisition device. The present invention also discloses an automatic detection method for cloud defects inside a crystal, which adopts the above-mentioned automatic detection device. The present invention realizes the automatic detection of cloud defects inside a crystal.

Description

Technical Field

[0001] The present invention belongs to the technical field of crystal internal defect detection, and in particular relates to an automatic detection device and method for crystal internal cloud defects. Background Art

[0002] Sapphire crystal is a single crystal mainly composed of aluminum oxide. It is widely used in many fields due to its excellent physical and chemical properties. First, sapphire has extremely high hardness, second only to diamond, so it is very resistant to wear and scratches. Secondly, it has excellent optical transparency in the ultraviolet, visible and infrared bands, which is suitable for manufacturing high-precision optical components. In addition, sapphire crystal has excellent thermal and chemical stability, can maintain its physical properties unchanged in high temperature and corrosive environment, and it is also a good electrical insulator. Based on these characteristics, sapphire is widely used in semiconductor and electronic fields, especially as a substrate material for light-emitting diodes and gallium nitride devices. In optical equipment, it is often used as a lens, infrared window and ultraviolet window. In addition, it is widely used in the scratch-resistant surface of high-end watches and mobile phones. In lasers, aerospace and military equipment, sapphire is also an ideal material because of its resistance to high-energy lasers, wear and corrosion. The above-mentioned fields have increasing requirements for the quality of sapphire crystals, especially its optical and mechanical properties. Therefore, higher requirements are also put forward for the detection of cloud defects inside the crystal.

[0003] Cloud defects are common body defects in sapphire crystals. Their presence seriously reduces the performance of the crystal and may even cause the entire crystal to be scrapped. Clouds are composed of bubbles, cavities or negative crystals (cavities with specific spatial shapes), which mainly come from: vacancies formed by atomic thermal motion; gases produced by reactions during growth; other impurity melts wrapped in the crystallization process, or aluminum oxide melt wrapped in due to fluctuations in growth rate, resulting in inconsistent volume shrinkage, and then forming cavities.

[0004] When the laser beam passes through the cloud area inside the crystal, it will produce obvious scattering phenomenon due to the Tyndall effect. By acquiring the scattered laser image through the image acquisition equipment, the cloud defects inside the crystal can be quantitatively analyzed.

[0005] The invention designs a novel automatic detection device and method for cloud defects inside a sapphire crystal. Summary of the invention

[0006] The purpose of the present invention is to provide an automated detection device and method for cloud defects inside a crystal, so as to solve the problems mentioned in the background technology that the current detection method for cloud defects in sapphire crystals is low in efficiency, has large detection errors, and the detection results are affected by many human factors.

[0007] To achieve the above-mentioned purpose, the present invention provides an automated detection device for cloud defects inside a crystal, comprising a main support, a rotating platform, a dot matrix laser module, an image acquisition device and a computer system;

[0008] The rotating platform includes a rotating platform base and a rotating platform bearing panel; the rotating platform is used to drive the crystal to be tested to rotate axially; the rotating platform base is fixedly connected to the bottom of the main support, the dot matrix laser module is arranged on the upper part of the main support, and the dot matrix laser module is located directly above the rotating platform bearing panel, the dot matrix laser module can move up and down relative to the main support, a dot laser light source distribution panel is arranged at the bottom of the dot matrix laser module, a plurality of point laser light sources are arranged on the point laser light source distribution panel, each point laser light source is controlled by an independent optical fiber lead-out switch, and the dot matrix laser module is used to generate a point laser beam; the image acquisition device is arranged on the side of the rotating platform bearing panel, and the image acquisition device is used to acquire the image of the crystal to be tested; the computer system is connected to the image acquisition device, and the computer system is used to process the image acquired by the image acquisition device.

[0009] In a specific embodiment, 3 to 8 slide grooves are arranged on the rotating platform bearing panel, all of which are radially distributed with respect to the center of the rotating platform bearing panel, and each slide groove is provided with a slider, and when all sliders move in the slide grooves, they expand or contract synchronously with respect to the center of the rotating platform bearing panel, so that all sliders always remain distributed on the same circle with respect to the center of the rotating platform bearing panel as the center when moving.

[0010] In a specific embodiment, the point laser light source distribution panel is circular, and a plurality of circular marking lines are arranged on the point laser light source distribution panel, all of which are centered on the center of the point laser light source distribution panel, and the differences in radius of adjacent circular marking lines are equal; the circular marking lines divide the point laser light source distribution panel into a circular area in the center and circular ring areas that expand successively; a point laser light source is arranged at the center of the circular area; three point laser light sources are arranged in each circular ring area, namely a first point laser light source, a second point laser light source, and a third point laser light source, and the first point laser light source in the circular ring area is 100 meters away from the circular ring area. The distance from the nearest point of the outer circular marking line is a, a is greater than 1mm, the distance from the second point laser light source in the circular ring area to the nearest point of the outer circular marking line of the circular ring area is 2a, and the distance from the third point laser light source in the circular ring area to the nearest point of the outer circular marking line of the circular ring area is 3a; taking the center of the point laser light source distribution panel as the vertex, the angle between the first point laser light source and the second point laser light source is β, the angle between the second point laser light source and the third point laser light source is also β, and the angle between the first point laser light source and the third point laser light source is 2β, β is greater than or equal to 30° and β is less than or equal to 60°.

[0011] In a specific implementation, the difference between the radii of adjacent circular markings is equal to the radius of the circular marking closest to the center of the point laser light source distribution panel.

[0012] In a specific embodiment, the two first point laser light sources of the adjacent annular regions are on the same straight line as the point laser light source at the center of the circular region, and the two first point laser light sources of the adjacent annular regions are respectively located on both sides of the point laser light source at the center of the circular region;

[0013] The two second point laser light sources in the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two second point laser light sources in the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area;

[0014] The two third point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two third point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area.

[0015] In a specific embodiment, the point laser light sources are all point laser light sources with a wavelength of 532nm or 650nm.

[0016] In a specific embodiment, the automatic detection device for cloud defects inside a crystal includes two groups of image acquisition devices, and the two groups of image acquisition devices are symmetrically distributed around the rotating platform bearing panel.

[0017] The present invention also provides an automated detection method for crystal internal cloud defects, which uses the automated detection device for crystal internal cloud defects as described above, and specifically includes the following steps:

[0018] First, place the crystal to be tested on a rotating platform; control some of the point laser light sources in the dot matrix laser module to light up to generate a point laser beam, turn on the image acquisition device, control the rotating platform to rotate one circle, and the image acquisition device synchronously and continuously collects image information of the crystal to be tested during its rotation. Change the lighted point laser light source in the dot matrix laser module and repeat the previous image acquisition process; after changing the lighted point laser light source several times, the computer system reconstructs a three-dimensional model of the crystal to be tested based on the collected image information.

[0019] In a specific implementation, after the crystal to be measured is placed on the rotating platform, the height of the lattice laser module is adjusted so that the distance between the bottom of the lattice laser module and the upper surface of the crystal to be measured is 5-10 mm.

[0020] In a specific implementation, the computer system reconstructs a three-dimensional model of the crystal to be measured according to the collected image information, as follows:

[0021] S1. First, use the image acquisition device to obtain the crystal at a distance from the center r The image sequence under the laser point illumination is n Frame, the resolution of each frame is h × w Pixels, that is h OK ，w List;

[0022] S2. Determine the effective detection area of ​​each frame image based on the spot position and diameter of the point laser beam at the incident end of the crystal S , which corresponds to the image's k Column to k+l List, S The size is h × l Pixels, that is h OK ，l List;

[0023] S3. Effective detection area S The edge detection of the image in the frame is performed to extract the scattered laser signal; the edge detection results on all frame images are spliced ​​in time sequence to form a resolution of h × nl The feature map of the pixel, i.e. h OK ，n × l List;

[0024] S4. To ensure that the reconstructed 3D model is consistent with the actual proportion of the detected crystal, it is necessary to H Distance from laser point to crystal rod center r The relationship between them is to scale the feature map. The resolution of the transformed feature map is h × m， in m is the number of row pixels after correction;

[0025] S5, mapping the value of each pixel point on the corrected feature map to a cylindrical surface of corresponding radius;

[0026] S6, changing the incident position of the laser point, repeating steps S1 to S5, and obtaining mappings of cylindrical surfaces with different radii; superimposing all mappings, a three-dimensional crystal model containing the cloud defect position information can be obtained.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. Automatic detection: In the detection process, the present invention does not need to manually move the crystal. The device will automatically control the rotation of the rotating platform and change the on and off conditions of each point laser in the dot matrix laser in real time, which greatly improves the efficiency of cloud defect detection;

[0029] 2. High efficiency, high precision, and quantification: The present invention can detect tiny volume cloud defects inside the crystal, shoot multiple groups of videos at the same time, improve detection efficiency, and can reconstruct through a three-dimensional model to give intuitive results;

[0030] 3. Wide application scope: The present invention is applicable to other transparent objects with cloud defects, such as glass, plastic, etc.

[0031] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention is further described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 It is a schematic diagram of a dot matrix laser module, a rotating platform, an image acquisition device and a crystal to be tested in an automated detection device for cloud defects inside a crystal according to the present invention;

[0034] Figure 2 It is a schematic diagram of a top view of a rotating platform of an automated detection device for cloud defects inside a crystal according to the present invention;

[0035] Figure 3 It is a schematic diagram of the placement position of the image acquisition device of the automatic detection device for cloud defects inside the crystal of the present invention and the upward viewing direction of the dot matrix laser module.

[0036] Among them, 1. Fractional laser module; 2. Rotating platform; 3. Crystal to be tested; 4. Image acquisition equipment. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] The present invention provides an automatic detection device for cloud defects inside a crystal, comprising a main support, a rotating platform 2, a dot matrix laser module 1, an image acquisition device 4 and a computer system;

[0039] The rotating platform includes a rotating platform base and a rotating platform bearing panel; the rotating platform is used to drive the crystal 3 to be tested to rotate axially; the rotating platform base is fixedly connected to the bottom of the main support; the dot matrix laser module is arranged on the upper part of the main support, and the dot matrix laser module is located directly above the rotating platform bearing panel, and the dot matrix laser module can move up and down relative to the main support; a dot laser light source distribution panel is arranged at the bottom of the dot matrix laser module, and a plurality of point laser light sources are arranged on the point laser light source distribution panel, each point laser light source is controlled by an independent optical fiber lead-out switch, and the dot matrix laser module is used to generate a point laser beam; the image acquisition device is arranged on the side of the rotating platform bearing panel, and the image acquisition device is used to acquire the image of the crystal to be tested; the computer system is connected to the image acquisition device, and the computer system is used to process the image acquired by the image acquisition device.

[0040] The shape of the point laser light source distribution panel includes but is not limited to circle and rectangle, and the number, spacing and distribution of the point laser light sources need to be able to detect the presence of cloud defects at different radii in the crystal alone or in combination.

[0041] The rotating platform bearing panel is provided with 3 to 8 slide grooves, all of which are radially distributed with the center of the rotating platform bearing panel, and each slide groove is provided with a slider, and when all sliders move in the slide grooves, they expand or contract synchronously with the center of the rotating platform bearing panel, so that all sliders always remain distributed on the same circle with the center of the rotating platform bearing panel as the center when moving.

[0042] The rotating platform bearing panel is movably arranged on the rotating platform base; the computer system controls the rotating platform bearing panel to rotate relative to the rotating platform base, so that the crystal to be tested on the rotating platform bearing panel rotates relative to the rotating platform base.

[0043] The point laser light source distribution panel is circular, and a plurality of circular marking lines are arranged on the point laser light source distribution panel, all of which are centered on the center of the point laser light source distribution panel, and the differences in the radii of adjacent circular marking lines are equal;

[0044] The circular marking line divides the point laser light source distribution panel into a circular area in the center and circular ring areas that expand successively;

[0045] A point laser light source is arranged at the center of the circular area;

[0046] Three point laser light sources are arranged in each circular ring area, namely, a first point laser light source, a second point laser light source, and a third point laser light source. The distance between the first point laser light source in the circular ring area and the nearest point of the outer circular marking line of the circular ring area is a, and a is greater than 1 mm. The distance between the second point laser light source in the circular ring area and the nearest point of the outer circular marking line of the circular ring area is 2a. The distance between the third point laser light source in the circular ring area and the nearest point of the outer circular marking line of the circular ring area is 3a. Taking the center of the point laser light source distribution panel as the vertex, the angle between the first point laser light source and the second point laser light source is β, the angle between the second point laser light source and the third point laser light source is also β, and the angle between the first point laser light source and the third point laser light source is 2β, and β is greater than or equal to 30° and β is less than or equal to 60°.

[0047] The differences between the radii of adjacent circular markings are all equal to the radius of the circular marking closest to the center of the point laser light source distribution panel.

[0048] The two first point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two first point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area;

[0049] The two second point laser light sources in the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two second point laser light sources in the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area;

[0050] The two third point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two third point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area.

[0051] The point laser light sources are all point laser light sources with a wavelength of 532nm or 650nm.

[0052] The automatic detection device for cloud defects inside a crystal comprises two groups of image acquisition devices, and the two groups of image acquisition devices are symmetrically distributed around the rotating platform bearing panel.

[0053] The present invention also provides an automated detection method for crystal internal cloud defects, which uses the automated detection device for crystal internal cloud defects as described above, and specifically includes the following steps:

[0054] First, place the crystal to be tested on a rotating platform; control some of the point laser light sources in the dot matrix laser module to light up to generate a point laser beam, turn on the image acquisition device, control the rotating platform to rotate one circle, and the image acquisition device synchronously and continuously collects image information of the crystal to be tested during its rotation. Change the lighted point laser light source in the dot matrix laser module and repeat the previous image acquisition process; after changing the lighted point laser light source several times, the computer system reconstructs a three-dimensional model of the crystal to be tested based on the collected image information.

[0055] After placing the crystal to be tested on the rotating platform, the height of the dot matrix laser module must be adjusted so that the distance between the bottom of the dot matrix laser module and the upper surface of the crystal to be tested is 5~10mm.

[0056] It is also necessary to adjust the height of the two sets of image acquisition devices located on the side and observe on the monitor of the computer system until the picture can just show the complete crystal shape, which can ensure that no information is missed during the shooting process and can also prevent the influence of other noises.

[0057] The computer system reconstructs a three-dimensional model of the crystal to be measured according to the collected image information, as follows:

[0058] S1. First, use the image acquisition device to obtain the crystal at a distance from the center r The image sequence under the laser point illumination is n Frame, the resolution of each frame is h × w Pixels, that is h OK ，w List;

[0059] S2. Determine the effective detection area of ​​each frame image based on the spot position and diameter of the point laser beam at the incident end of the crystal S , which corresponds to the image's k Column to k+l List, S The size is h × l Pixels, that is h OK ，l List;

[0060] S3. Effective detection area S The edge detection results on all frame images are spliced ​​in chronological order to form a resolution of h × nl The feature map of the pixel, i.e. h OK ，n × l List;

[0061] S4. To ensure that the reconstructed 3D model is consistent with the actual proportion of the detected crystal, it is necessary to H Distance from laser point to crystal rod center r The relationship between them is to scale the feature map. The resolution of the transformed feature map is h × m， in m is the number of row pixels after correction.

[0062] S5, mapping the value of each pixel point on the corrected feature map to a cylindrical surface of corresponding radius;

[0063] S6, changing the incident position of the laser point, repeating steps S1 to S5, and obtaining mappings of cylindrical surfaces with different radii. All mappings are superimposed to obtain a crystal three-dimensional model containing the cloud defect position information.

[0064] Example 1

[0065] This implementation uses a cylindrical sapphire crystal rod with a diameter of 100 mm as the test object, i.e. the crystal to be tested.

[0066] An automatic detection device for cloud defects inside a crystal, comprising a main support, a rotating platform 2, a dot matrix laser module 1, an image acquisition device 4 and a computer system;

[0067] The rotating platform comprises a rotating platform base and a rotating platform bearing panel;

[0068] The rotating platform bearing panel is horizontally rotatable and arranged on the rotating platform base, and the computer system controls whether the rotating platform bearing panel is horizontally rotated; the rotating platform bearing panel is used to place the crystal to be tested;

[0069] The rotating platform base is fixedly connected to the bottom of the main body bracket.

[0070] The rotating platform bearing panel is provided with 4 slide grooves, all of which are radially distributed with respect to the center of the rotating platform bearing panel, and each slide groove is provided with a slider, and when all the sliders move in the slide grooves, they are synchronously expanded or contracted with respect to the center of the rotating platform bearing panel, so that when all the sliders move, they are always distributed on the same circle with respect to the center of the rotating platform bearing panel as the center. When placing the crystal to be tested, the slider is contracted toward the center of the rotating platform bearing panel to ensure that the crystal to be tested is in the center position of the rotating platform bearing panel.

[0071] In this embodiment, the rotating platform base is an optical electric rotating table, and preferably the optical electric rotating table is an optical electric rotating table of model YXRA100 including a servo motor.

[0072] The rotating platform bearing panel includes a crystal bearing plate, 4 micro linear guide linear modules and 4 crystal contact blocks. The crystal bearing plate is provided with 4 long strip holes radially distributed from the center of the crystal bearing plate. Each micro linear guide linear module is correspondingly arranged below a long strip hole to form a slide groove. The motor ends of the micro linear guide linear modules are all arranged on the inner side, and the 4 micro linear guide linear modules are synchronously controlled by the same controller; the crystal contact block is fixedly arranged on the slide table of the micro linear guide linear module, and the crystal contact block is made of rubber.

[0073] The preferred micro linear guide linear module is the micro linear guide linear module model FSK30J-T4-E100-BC-B35.

[0074] The rotating platform bearing panel is fixedly arranged on the table surface of the optical electric rotating table.

[0075] The optical electric rotating stage and the four micro linear guide linear modules are all connected to the computer system. Since the diameter of the crystal to be tested is known, the data is input into the computer system. When the crystal to be tested is placed on the rotating platform bearing panel, the computer system controls the slides of the four micro linear guide linear modules to shrink synchronously, so that the crystal contact block on the slide will push the crystal to be tested to the center of the rotating platform bearing panel. The computer system can also control the precise rotation of the optical electric rotating stage to make the crystal to be tested rotate exactly one circle.

[0076] The dot matrix laser module is arranged on the upper part of the main support, and the dot matrix laser module is located directly above the rotating platform bearing panel. The dot matrix laser module can move up and down relative to the main support, so that the distance between the bottom of the dot matrix laser module and the upper surface of the crystal to be measured is 5~10mm during shooting.

[0077] The bottom of the dot matrix laser module is a circular point laser light source distribution panel.

[0078] Five circular marking lines are also arranged on the point laser light source distribution panel. All the circular marking lines have the center of the point laser light source distribution panel as the center of the circle, and the differences in the radii of adjacent circular marking lines are all equal.

[0079] Five circular markings divide the point laser light source distribution panel into a circular area in the center and four circular ring areas that expand successively. The four circular ring areas are the first circular ring area, the second circular ring area, the third circular ring area, and the fourth circular ring area from the outside to the inside. The radius of the outermost circular marking is 50 mm, and the difference in radius between adjacent circular markings is 10 mm.

[0080] A plurality of point laser light sources are arranged on the point laser light source distribution panel. Each point laser light source is led out by an independent optical fiber, and the independent opening and closing of each point laser light source is controlled by an integrated controller, and the integrated controller is controlled by a computer system, thereby realizing the independent opening and closing of any point laser light source or a combination of point laser light sources controlled by the computer system.

[0081] A point laser light source is arranged at the center of the circular area.

[0082] Three point laser light sources are arranged in each circular area, namely, the first point laser light source, the second point laser light source and the third point laser light source. The distance between the first point laser light source in the circular area and the nearest point of the outer circular marking line of the circular area is 3mm, the distance between the second point laser light source in the circular area and the nearest point of the outer circular marking line of the circular area is 6mm, and the distance between the third point laser light source in the circular area and the nearest point of the outer circular marking line of the circular area is 9mm; taking the center of the point laser light source distribution panel as the vertex, the angle between the first point laser light source and the second point laser light source is 45°, the angle between the second point laser light source and the third point laser light source is also 45°, and the angle between the first point laser light source and the third point laser light source is 90°.

[0083] The two first point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two first point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area;

[0084] The two second point laser light sources in the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two second point laser light sources in the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area;

[0085] The two third point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two third point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area.

[0086] The axis center line of the circular marking line of the dot matrix laser module and the axis center line of the rotation of the rotating platform bearing panel are the same straight line.

[0087] The point laser light sources are all point laser light sources with a wavelength of 532nm or 650nm.

[0088] The automatic detection device for cloud defects inside a crystal comprises two groups of image acquisition devices, which are arranged on the sides of a rotating platform bearing panel, and the two groups of image acquisition devices are symmetrically distributed with the rotating platform bearing panel as the center.

[0089] The computer system is connected to the image acquisition device, and the computer system is used to process the images acquired by the image acquisition device to display the situation of the cloud defect inside the crystal to be tested.

[0090] The present invention also provides an automated detection method for cloud defects inside a crystal, which adopts the automated detection device for cloud defects inside a crystal.

[0091] The specific steps are as follows:

[0092] First, place the crystal to be tested on the rotating platform, and adjust the position of the slider on the platform slide slot so that the sliders in four directions are exactly tangent to the side of the crystal to be tested, ensuring that the center of the bottom surface of the crystal to be tested coincides with the center of the rotating platform;

[0093] Then adjust the height of the dot matrix laser so that it is at a certain distance from the upper surface of the crystal; preferably maintain a distance of 5 to 10 mm.

[0094] Adjust the height of the two sets of image acquisition devices on the side and observe on the monitor of the computer system until the picture can just show the complete crystal shape, which can ensure that no information is missed during the shooting process and prevent the influence of other noises;

[0095] After the detection starts, the computer system controls some of the point laser light sources in the dot matrix laser module to light up according to a pre-set program to generate a point laser beam, turns on the image acquisition device, and the rotating platform starts to rotate at the same time; after one rotation, the situation of the lit point laser light sources in the dot matrix laser module changes, and the image acquisition device transmits a set of picture sequences to the computer system, and the rotating platform rotates again; after repeating several times, the detection ends, the dot matrix lasers are all turned off, and the rotating platform and image acquisition device stop running.

[0096] The following is a detailed description of how the fractional laser and rotating platform work:

[0097] Before the first rotation, the dot lasers in the first and second circular ring areas on the outside of the dot laser are controlled to light up, the rotating platform starts to rotate, and the two sets of image acquisition devices start shooting; after the rotating platform rotates one circle, the dot lasers in the first and second circular ring areas on the outside of the dot laser are all turned off, the dot lasers in the third and fourth circular ring areas on the outside are lit, and the rotating platform rotates again; after the rotating platform rotates one circle, the dot lasers in the third and fourth circular ring areas on the outside of the dot laser are all turned off, the rotating platform is turned off, and the dot lasers in the circular areas light up for 1 second and then turn off.

[0098] The entire process ensures that the image acquisition equipment can obtain the cloud defect information on the side surface of the crystal to be tested at different depths and complete all-round detection.

[0099] The computer system reconstructs a three-dimensional model of the crystal to be measured according to the collected image information, as follows:

[0100] S1. First, use the image acquisition device to obtain the crystal at a distance from the center r The image sequence under the illumination of the laser point is n Frame, the resolution of each frame is h × w Pixels, that is h OK ，w List;

[0101] S2. Determine the effective detection area of ​​each frame image based on the spot position and diameter of the point laser beam at the incident end of the crystal S , which corresponds to the image's k Column to k+l List, S The size is h × l Pixels, that is h OK ，l List;

[0102] S3. Effective detection area S The edge detection results on all frame images are spliced ​​in chronological order to form a resolution of h × nl The feature map of the pixel, i.e. h OK ，n × l List;

[0103] S4. To ensure that the reconstructed 3D model is consistent with the actual proportion of the detected crystal, it is necessary to H Distance from laser point to crystal rod center r The relationship between them is to scale the feature map. The resolution of the transformed feature map is h × m， in m is the number of row pixels after correction.

[0104] S5, mapping the value of each pixel point on the corrected feature map to a cylindrical surface of corresponding radius;

[0105] S6, changing the incident position of the laser point, repeating steps S1 to S5, and obtaining mappings of cylindrical surfaces with different radii. All mappings are superimposed to obtain a crystal three-dimensional model containing the cloud defect position information.

[0106] At this point, the detection of cloud defects inside the crystal is completed.

[0107] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. An automatic detection device for cloud defects inside a crystal, characterized in that: It comprises a main body support, a rotating platform (2), a dot matrix laser module (1), an image acquisition device (4) and a computer system; The rotating platform (2) comprises a rotating platform base and a rotating platform bearing panel; the rotating platform (2) is used to drive the crystal to be tested (3) to rotate along the axial direction; the rotating platform base is fixedly connected to the bottom of the main support; the dot matrix laser module (1) is arranged on the upper part of the main support, and the dot matrix laser module (1) is located directly above the rotating platform bearing panel, and the dot matrix laser module can move up and down relative to the main support, and the bottom of the dot matrix laser module is provided with a dot laser light source distribution panel, and a plurality of dot laser light sources are arranged on the dot laser light source distribution panel, each of which is controlled by an independent optical fiber lead-out switch, and the dot matrix laser module is used to generate a dot laser beam; the image acquisition device (4) is arranged on the side of the rotating platform bearing panel, and the image acquisition device (4) is used to acquire an image of the crystal to be tested (3); the computer system is connected to the image acquisition device (4), and the computer system is used to process the image acquired by the image acquisition device; The rotating platform bearing panel is provided with 3 to 8 slide grooves, all of which are radially distributed with the center of the rotating platform bearing panel, and each slide groove is provided with a slider, and when all sliders move in the slide grooves, they expand or contract synchronously with the center of the rotating platform bearing panel, so that all sliders always remain distributed on the same circle with the center of the rotating platform bearing panel as the center when moving.

2. The automatic detection device for cloud defects inside a crystal according to claim 1, characterized in that: The point laser light source distribution panel is circular, and a plurality of circular marking lines are arranged on the point laser light source distribution panel, all of which are centered on the center of the point laser light source distribution panel, and the differences in radius of adjacent circular marking lines are equal; the circular marking lines divide the point laser light source distribution panel into a circular area in the center and circular ring areas that expand successively; a point laser light source is arranged at the center of the circular area; three point laser light sources are arranged in each circular ring area, namely a first point laser light source, a second point laser light source, and a third point laser light source, and the first point laser light source in the circular ring area is 100 times closer to the outer circular marking line of the circular ring area than the outer circular marking line of the circular ring area. The closest distance to the line is a, a is greater than 1mm, the distance between the second point laser light source in the circular ring area and the closest point of the outer circular marking line of the circular ring area is 2a, and the distance between the third point laser light source in the circular ring area and the closest point of the outer circular marking line of the circular ring area is 3a; taking the center of the point laser light source distribution panel as the vertex, the angle between the first point laser light source and the second point laser light source is β, the angle between the second point laser light source and the third point laser light source is also β, and the angle between the first point laser light source and the third point laser light source is 2β, β is greater than or equal to 30° and β is less than or equal to 60°.

3. The automatic detection device for cloud defects inside a crystal according to claim 2, characterized in that: The differences between the radii of adjacent circular markings are all equal to the radius of the circular marking closest to the center of the point laser light source distribution panel.

4. The automatic detection device for cloud defects inside a crystal according to claim 2, characterized in that: The two first point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two first point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area; The two second point laser light sources in the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two second point laser light sources in the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area; The two third point laser light sources of the adjacent circular ring areas are on the same straight line as the point laser light source at the center of the circular area, and the two third point laser light sources of the adjacent circular ring areas are respectively located on both sides of the point laser light source at the center of the circular area.

5. The automatic detection device for cloud defects inside a crystal according to claim 1, characterized in that: The point laser light source is a point laser light source with a wavelength of 532nm or 650nm.

6. The automatic detection device for crystal internal cloud defects according to claim 1, characterized in that: The automatic detection device for cloud defects inside a crystal comprises two groups of image acquisition devices, and the two groups of image acquisition devices are symmetrically distributed around the rotating platform bearing panel.

7. An automated method for detecting cloud defects inside a crystal, characterized in that: The automatic detection device for cloud defects inside a crystal as claimed in any one of claims 1 to 6 is used, and specifically comprises the following steps: First, place the crystal to be tested on the rotating platform; control some of the point laser light sources in the dot matrix laser module to light up to generate a point laser beam, turn on the image acquisition device, control the rotating platform to rotate one circle, and the image acquisition device synchronously and continuously collects image information during the rotation of the crystal to be tested, change the lighted point laser light source in the dot matrix laser module, and repeat the previous image acquisition process; After changing the lighted point laser light source several times, the computer system reconstructs the three-dimensional model of the crystal to be tested based on the collected image information.

8. The method for automatically detecting cloud defects inside a crystal according to claim 7, characterized in that: After the crystal to be measured is placed on the rotating platform, the height of the lattice laser module is adjusted so that the distance between the bottom of the lattice laser module and the upper surface of the crystal to be measured is 5-10 mm.

9. The method for automatically detecting cloud defects inside a crystal according to claim 7, characterized in that: The computer system reconstructs a three-dimensional model of the crystal to be measured according to the collected image information, as follows: S1. First, use the image acquisition device to obtain the crystal at a distance from the center r The image sequence under the laser point illumination is n Frame, the resolution of each frame is h × w Pixels, that is h OK ，w List; S2. Determine the effective detection area of ​​each frame image based on the spot position and diameter of the point laser beam at the incident end of the crystal S , which corresponds to the image's k Column to k+l List, S The size is h × l Pixels, that is h OK ，l List; S3. Effective detection area S Perform edge detection on the image inside and extract the scattered laser signal; The edge detection results on all frame images are spliced ​​in chronological order to form a resolution of h × nl The feature map of the pixel, i.e. h OK ，n×l List; S4. To ensure that the reconstructed 3D model is consistent with the actual proportion of the detected crystal, it is necessary to H Distance from laser point to crystal rod center r The relationship between them is to scale the feature map. The resolution of the transformed feature map is h × m， in m is the number of row pixels after correction; S5, mapping the value of each pixel point on the corrected feature map to a cylindrical surface of corresponding radius; S6, changing the incident position of the laser point, repeating steps S1 to S5, and obtaining mappings of cylindrical surfaces with different radii; superimposing all mappings, a three-dimensional crystal model containing the cloud defect position information can be obtained.

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