Intelligent portable 3D anti-overexposure part defect detection device and method

Abstract

The application relates to a kind of intelligent portable 3D anti-overexposure part defect detection devices and methods, for industrial vision detection field.Its technical scheme: by protection box, detection table telescopic system, projection-imaging system, workpiece rotating system, main control system, indicating lamp module composition;Protection box includes protection box cover and protection box body;Detection table telescopic system includes guide rail frame, detection table, plane mirror installation groove, handle, limit module;Projection-imaging system includes industrial projector, camera, plane mirror;Workpiece rotating system includes workpiece rotating disc and rotating disc drive module;Main control system includes control module, reset button, host computer;Indicating lamp module includes standby indicating lamp, working indicating lamp;The device is intelligent, high integration, avoids the easy overexposure problem of stripe projection three-dimensional measurement through double light path design, reduces hardware cost.

Description

TECHNICAL FIELD

[0001] The present application relates to a device for part defect detection, which is a device for realizing three-dimensional reconstruction of high-reflective parts by using a double optical path system combined with monocular structured light technology, and is used in the field of industrial vision detection. BACKGROUND

[0002] With the rapid development of computer vision, optical sensing and signal processing technology, three-dimensional reconstruction technology has been widely applied in various fields, such as industrial detection, medical imaging, virtual reality, augmented reality, robot navigation and cultural heritage protection. At present, the three-dimensional reconstruction method based on structured light projection has attracted widespread attention due to its high precision, real-time performance, low cost, easy integration and implementation, etc.

[0003] The industrial field requires to realize high-precision and high-efficiency part defect detection. The traditional detection methods such as manual detection and contact detection have problems such as low detection efficiency, high cost and workpiece easy to be worn. At present, many non-contact part defect detection devices have emerged in the market. However, for metal parts with high-reflective surface, the stripe projection three-dimensional measurement is easy to cause the overexposure of the captured image, and it is difficult to realize high-precision defect detection. The existing solutions to this problem mostly use multiple exposure method, adaptive stripe projection and deep learning-based method, but the above methods have complex algorithm architecture and cannot meet the demand of rapid online detection. Or through hardware-assisted method, but the hardware structure is complex and the detection cost is high. Therefore, it is urgent to design a non-contact part defect detection device with simple execution architecture, low cost and intelligence, which can effectively solve the problem of image overexposure. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, an intelligent portable 3D anti-overexposure part defect detection device and method are provided, which solves the problem of overexposure of the captured image caused by stripe projection three-dimensional measurement, and achieves the purpose of three-dimensional reconstruction of high-reflective parts.

[0005] The technical scheme of the intelligent portable 3D anti-overexposure part defect detection device and method of the present application comprises:

[0006] The utility model provides an intelligent portable 3D anti-overexposure part defect detection device, including protection box, detection table telescopic system, projection -imaging system, work piece rotating system, main control system, pilot lamp module, the protection box includes protection box cover, protection box body, and protection box cover and protection box body realize flexible opening and closing with hinge connecting structure, detection table telescopic system includes guide rail frame, detection table, plane mirror installation groove, handle, limiting module, guide rail frame is located in the protection box body inside, is connected with each other through limiting module and detection table, handle adopts recessed structure, is located detection table front side, is used for controlling detection table movement, plane mirror installation groove is located detection table right side, installs plane mirror on plane mirror installation groove, projection -imaging system includes industrial projector, camera, plane mirror, and industrial projector and camera are installed on the upper surface of guide rail frame according to the principle of similar triangle, and plane mirror is installed on plane mirror installation groove, work piece rotating system is composed of work piece rotating disc and rotating disc drive module, and work piece rotating disc is installed on the top of detection table, and rotating disc drive module is located in the inside of detection table, the pilot lamp module includes standby pilot lamp and working pilot lamp, and standby pilot lamp and working pilot lamp are all set up in the right side of protection box body, and the main control system includes control module, reset button, host computer, control module is fixed on the upper surface of guide rail frame, reset button is set up in the left side of working pilot lamp, and host computer is connected with the device through data line.

[0007] The limiting module in the detection table telescopic system is composed of a lock head A with an elastic rod A, a guide rail A, a lock head B with an elastic rod B, and a guide rail B. The limiting module has a left-right symmetrical mechanical mechanism. The guide rail A has a plurality of clamping grooves. The elastic rod A is an elastic slender metal strip. The lock head A moves in the guide rail A. When it is static, the lock head A is embedded in the clamping groove to realize the limiting function. The guide rail B has a plurality of clamping grooves. The elastic rod B is an elastic slender metal strip. The lock head B moves in the guide rail B. When it is static, the lock head B is embedded in the clamping groove to realize the limiting function.

[0008] A smart, portable 3D anti-overexposure part defect detection device includes a workpiece rotation system. The rotating disk drive module comprises a pressure sensor, a motor, and a coupling. The motor is connected to the workpiece rotating disk via the coupling. The center of the workpiece rotating disk and the motor's output shaft are on the same vertical line. The pressure sensor is installed below the workpiece rotating disk to detect the pressure value above it. The main control system controls the motor's start and stop based on the pressure value. The motor drives the workpiece rotating disk to control the rotation angle of the workpiece under test. The projection-imaging system is used to acquire workpiece view information. A camera and an industrial projector are located in front of the workpiece under test. The plane mirror is located on the side of the workpiece to be measured, and the camera acquires dual-view information of the workpiece in real time. The main control system is used to control the operation of the entire device and process and analyze image information. The control module of the main control system consists of a data storage module, a data transmission module, a synchronization trigger module, and a main controller. The data storage module is used to buffer the received data, and the main controller is used for data processing, analysis, judgment, and issuing instructions to control the operating status of the entire device. The data transmission module is used to send image information to the host computer, and the synchronization trigger module is used to control the camera and industrial projector to capture and project synchronously. The reset button controls the main control system to return to the standby state.

[0009] A detection method using an intelligent portable 3D anti-overexposure part defect detection device involves capturing an image frame from two different perspectives of the workpiece during inspection. The right view is the view directly acquired by the camera, while the left view is the view indirectly acquired through plane mirror imaging. The camera corresponding to the left view is designated as a virtual camera. Both the physical camera and the virtual camera are calibrated, and their respective intrinsic parameter matrices are obtained. , extrinsic matrix , ;

[0010] A striped image is projected onto the surface of the object. The camera captures the image and obtains the corresponding grayscale value distribution map. The grayscale value is checked pixel by pixel to see if it is equal to 255. If it is equal to 255, the point is a saturated pixel. The proportion of saturated pixels is counted. When the proportion is greater than the threshold, the workpiece is determined to be a metal workpiece, and the automatic adjustment device is set to dual-view detection mode. When the proportion is less than the threshold, the workpiece is determined to be a general workpiece, and the adjustment mode is set to single-view detection mode.

[0011] In single-view inspection mode, the right view information is used to restore the three-dimensional shape of the workpiece under test and detect defect information, without using the left view information;

[0012] In dual-view detection mode, the original image acquired by the camera is processed as follows: the right view information is denoted as image 1, the left view information is mirrored and flipped, and denoted as image 2, generating an overexposed area mask for image 1. , Mask region serial number, Mask region coordinates, Current pixel gray value, in image 1, select mask Edge of a pixel point coordinates as anchor point coordinates And with anchor point coordinates as the base point to generate a 5x5 window region, in image 2, select an anchor point coordinates Image 2 generates a window region of the same size, in the current line according to

[0013]

[0014] Find out the matching cost of each pixel point of image 2, the smaller the matching cost, the higher the matching degree of the point , wherein Is the matching window centered on the pixel , , The gray value of image 1 and image 2 at , Coordinate point, Disparity, Weight function, The weight function Is determined by the overexposure area mask And the gradient weighting factor The calculation formula is

[0015]

[0016] Among them, To avoid the minimum value of the denominator being zero, The gradient vector of image 1 at the current pixel coordinates, is obtained by

[0017]

[0018] , And Respectively, the horizontal direction gradient and the vertical direction gradient, The average gradient in the window is obtained by , The number of pixel points in the window, set to =25, Indicates the gradient, according to the above formula to obtain the matching information of the pixel points of the mask edge of image 1, then map the mask of image 1 to the corresponding region of image 2, compensate image 1 through the corresponding region information of image 2, finally, through the phase shift method, three-dimensional reconstruction of the workpiece is carried out and the defect information is obtained.

[0019] The beneficial effects of the present application are: 1. A monocular camera is used to obtain different view angle images through double light paths, the image overexposure problem in the imaging process is solved, the system architecture is simplified, and the hardware cost is reduced; 2. The spacing control between the measured object and the camera is realized by using the spacing function of the spacing module, and the field of view of the camera shooting is flexibly adjusted; 3. The system is integrated in a protective box and has intelligent control function, which can adapt to different application requirements of operation scene. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present application.

[0021] Figure 2 It is a schematic diagram of the workpiece rotating system structure of the present application.

[0022] Figure 3 It is a schematic diagram of the spacing module structure of the present application.

[0023] Figure 4 It is a schematic diagram of the main control system.

[0024] In the figure: 1, protective box cover, 2, protective box body, 3, guide rail frame, 4, detection table, 5, plane mirror mounting groove, 6, handle, 7, industrial projector, 8, camera, 9, plane mirror, 10, workpiece rotating disc, 11, pressure sensor, 12, motor, 13, control module, 14, standby indicator light, 15, working indicator light, 16, reset button, 17, spacing module, 18, lock head A, 19, elastic rod A, 20, guide rail A, 21, guide rail B, 22, rotating disc driving module, 23, coupling, 24, main control unit, 25, data storage module, 26, data transmission module, 27, upper computer, 28, synchronous trigger module, 29, lock head B, 30, elastic rod B. DETAILED DESCRIPTION

[0025] The present application will be further described below in conjunction with the accompanying drawings Figure 1 、 2 , 3, 4.

[0026] The protective box is the outer protective structure of the whole device, and the protective box cover 1 can be opened as needed to meet the debugging needs of the internal industrial projector 7 and the camera 8; when the protective box cover 1 is closed, it can effectively realize the dust protection of the industrial projector 7 and the camera 8;

[0027] When the device is stored or needs to be transported, the plane mirror mounting groove 5 is in an idle state, the detection table 4 is retracted to the innermost position of the protective box body 2, the motor 12 is in a stopped and stationary state, the standby indicator light 14 and the working indicator light 15 are both extinguished, and the protective box cover 1 is closed, which is convenient for storage and transportation of the whole device;

[0028] When the device is powered on, the standby indicator light 14 is on, and the device is in standby state; the limiting module 17 plays a limiting role on the detection table 4, according to the detection requirement, the operator operates the handle 6 to pull the detection table 4 outward, the lock head A 18 and the lock head B 29 are sequentially passed through the clamping groove under the action of the elastic rod A 19 and the elastic rod B 30 along the guide rail A 20 and the guide rail B 21, and stop operating the handle 6 after reaching the target position, the lock head A 18 and the lock head B 29 are embedded into the corresponding clamping groove to lock the detection table 4;

[0029] The mirror 9 is installed on the mirror mounting groove 5, the industrial projector 7, the camera 8 and the mirror 9 constitute the projection-imaging system of the device, wherein the camera 8 and the industrial projector 7 are located in front of the workpiece to be measured, and the mirror 9 is located on the right side of the workpiece to be measured, and the whole detection process is divided into a calibration stage and a measurement stage;

[0030] In the calibration stage, a pinhole imaging model is established , wherein, is the three-dimensional coordinates of any point of the object to be measured, is the image coordinates of the point in the image coordinate system, is the scale factor, is the rotation matrix and the translation matrix is the parameter matrix describing the transformation from the world coordinate system to the camera coordinate system, is the camera intrinsic matrix, which can be expressed as , and are the focal lengths in the horizontal and vertical directions respectively, and are the camera principal point coordinates, the camera 8 and the virtual camera are calibrated to obtain their respective intrinsic matrices , and extrinsic , , and the geometric correspondence relationship between the components is established;

[0031] In the measurement stage, the pressure sensor 11 carried under the workpiece rotating disc 10 detects the current pressure value and transmits it to the control module 13, the data storage module 25 in the control module 13 stores the pressure value information, and the host controller 24 analyzes and judges the current pressure value information, when a workpiece is placed on the workpiece rotating disc 10, the host controller 24 monitors the sudden change of the pressure value information, and judges whether it is a false touch at intervals of 5 seconds, if the pressure value is reduced to the initial value again within 5 seconds, the host controller 24 judges that it is a false touch, if the pressure value remains unchanged after 5 seconds, the host controller 24 wakes up the device to enter the working state, at this time the working indicator light 15 is on and the standby indicator light 14 is off;

[0032] After entering the working state, the host computer 27 performs initial determination to confirm the workpiece type, and the specific steps are as follows: the industrial projector 7 projects a stripe image onto the surface of the object, the camera 8 captures one frame of image, the image information is sent to the host computer 27 through the data sending module 26 in the control module 13, the host computer 27 counts the proportion of saturated pixel points, when the proportion is greater than the threshold value, it is determined that the workpiece is a metal workpiece, and the host computer 24 adjusts the detection mode of the device to a double-view detection mode, when the proportion is less than the threshold value, it is determined that the workpiece is a general workpiece, and the detection mode is adjusted to a single-view detection mode;

[0033] After the initial determination is completed, the host computer 24 controls the motor 12 to start and drive the workpiece rotating disc 10 to rotate, if the workpiece to be detected is removed in advance before the detection is completed, the device returns to the standby state, and the image data transmission is terminated;

[0034] In the single-view detection mode, only the right-view information is used, the industrial projector 7 projects a sinusoidal grating with continuously changing phase onto the workpiece to be detected

[0035]

[0036] The camera 8 captures the current grating image in real time and sends it to the host computer 27 through the data sending module 26, and the host computer 27 performs three-dimensional reconstruction and defect analysis of the workpiece;

[0037] In the double-view detection mode, the industrial projector 7 projects a sinusoidal grating with continuously changing phase onto the workpiece to be detected

[0038]

[0039] The camera 8 synchronously captures the current grating image, flips the left-view information of the image to mirror image, and records it as image 1, and the right-view information is recorded as image 2, and generates a overexposure area mask of image 1 , wherein is the serial number of the mask area, is the mask area coordinate, is the current coordinate pixel grayscale value, and then an anchor point coordinate is selected at the edge of the mask area of image 1 and a window is constructed based on the anchor point coordinate, and the window size is 5x5, and a window of the same size is used to cover the anchor point coordinate in image 2 , and the matching cost of the two coordinates is obtained through

[0040]

[0041] , wherein , is the grayscale value of image 1 and image 2 at , coordinate point, is the parallax, Indicates the coordinates in the image At this location, the parallax is The matching cost at that time; the smaller the value, the higher the degree of matching. For the weight function, Weighting function Overexposed area mask and gradient weighting factor The decision is made jointly, and the calculation formula is as follows:

[0042]

[0043] in, To avoid the minimum value where the denominator is zero, Let be the gradient vector of image 1 at the current pixel coordinates, calculated using the following formula:

[0044]

[0045] in and These are the horizontal gradient and the vertical gradient, respectively. The average gradient within the window is given by... Find out, This refers to the number of pixels within the window. =25, This represents the gradient. Pixels with higher gradients correspond to regions with rich texture details in the image and have higher weights, while pixels with lower gradients correspond to smooth regions in the image and have lower weights. By moving this window in Image 2, we obtain the points. Corresponding to of ,in Then in image 2 For image 1 The matching points are then identified, and the above steps are repeated to obtain matching information for all pixels. The truncated phases are solved, and the truncated phase distribution maps of Images 1 and 2 are obtained. , The masked area of ​​image 1 is determined by matching information. Mapped to image 2, using Phase information compensation in the corresponding region The missing phase information is used to construct the three-dimensional shape of the workpiece under test and identify surface defect information of the workpiece.

[0046] After the workpiece rotating disc 10 rotates 360 degrees, the camera 8 obtains all surface information of the workpiece to be measured, and transmits the information to the upper computer 27 through the data transmission module 26. At this time, the host controller 24 controls the motor 12 to stop running, and then waits for the operating personnel to remove the workpiece that has completed the measurement from the workpiece rotating disc 10. When the workpiece is separated from the workpiece rotating disc 10, the pressure value decreases. After the host controller 24 detects that the pressure value decreases, it sends a command to control the device to switch back to the standby state. At this time, the standby indicator light 14 is on, and the working indicator light 15 is off. Pressing the reset button 16 during the detection process will cause the host controller 24 to send a command to make the data storage module 25 empty all data of this detection, and control the device to enter the standby state.

[0047] After the detection is completed, the power is turned off, the plane mirror 9 is taken off from the plane mirror installation slot 5, and the operating personnel operates the handle 6 to control the detection table 4 to retreat into the protective box body 2.

Claims

1. A smart, portable 3D anti-overexposure part defect detection method, characterized in that: In a frame of an image captured by the camera (8), there are image information from two different perspectives of the workpiece to be measured. The right view is the view directly obtained by the camera (8), and the left view is the view indirectly obtained by imaging through the plane mirror (9). Let the left view be the virtual camera view. The camera (8) and the virtual camera are calibrated to obtain their respective intrinsic parameter matrices A1 and A2, and extrinsic parameter matrices [R1 T1] and [R2 T2]. Project a striped image onto the surface of the object, the camera (8) captures the image and obtains the corresponding grayscale value distribution map, the host computer (27) counts the proportion of saturated pixels, when the proportion is greater than the threshold, the workpiece is determined to be a metal workpiece, the automatic adjustment device works in dual-view detection mode, when the proportion is less than the threshold, the workpiece is determined to be a general workpiece, the adjustment working mode is single-view detection mode. In single-view inspection mode, the right view information is used to restore the three-dimensional shape of the workpiece under test and detect defect information, without using the left view information; In dual-view detection mode, the original image acquired by camera (8) is processed as follows: the right view information is denoted as image 1, the left view information is mirrored and flipped, and denoted as image 2, and an overexposed area mask of image 1 is generated. n is the mask region index, (x, y) are the mask region coordinates, and C(x, y) is the gray value of the current pixel. In image 1, mask M is selected. n The coordinates of a pixel on the edge (x, y) are the coordinates of the anchor point (x). r1 y r1 ), and generate a 5×5 window region with the anchor point coordinates as the base point, and select an anchor point coordinate (x) in image 2. l1 y l1 In Image 2, a window region of the same size is generated, and in the current row, according to... Calculate the matching cost for each pixel in image 2. The smaller the matching cost, the closer the match is to the point (x). r1 y r1 The higher the matching degree, the better. Here, Q(x, y) is the matching window centered at pixel (x, y), R(x+i, y+j) and L(x+d+i, y+j) are the grayscale values ​​of image 1 and image 2 at coordinates (x+i, y+j) and (x+d+i, y+j), respectively, d is the disparity, and w(x, y) is the weight function, w(x, y) ∈ [0, 1]. The weight function w(x, y) is determined by the overexposed region mask M. n The gradient weighting factor α(x, y) and the gradient weighting factor α(x, y) are jointly determined, and the calculation formula is as follows: Where ∈ is used to avoid the minimum value where the denominator is zero. Let be the gradient vector of image 1 at the current pixel coordinates, given by We obtain G x (x, y) and G y (x, y) represent the horizontal and vertical gradients, respectively. The average gradient within the window is given by... Find N, where N is the number of pixels within the window, and set N = 25. The gradient is represented by the above formula. The matching information of the edge pixels of the mask in image 1 is obtained. Then, the mask of image 1 is mapped to the corresponding area of ​​image 2. The information of the corresponding area of ​​image 2 is used to compensate for image 1. Finally, the workpiece is reconstructed in three dimensions and the defect information is obtained by phase shifting method. An intelligent portable 3D anti-overexposure part defect detection device is used for detection. The intelligent portable 3D anti-overexposure part defect detection device includes a protective box, a detection table telescopic system, a projection-imaging system, a workpiece rotation system, a main control system, and an indicator light module. The protective box includes a protective box cover (1) and a protective box body (2). The protective box cover (1) and the protective box body (2) are connected by a hinge structure to achieve flexible opening and closing. The detection table telescopic system includes a guide rail frame (3), a detection table (4), a plane mirror mounting slot (5), a handle (6), and a limiting module (17). The guide rail frame (3) is located inside the protective box body (2) and is connected to the detection table (4) through the limiting module (17). The handle (6) adopts a recessed structure and is located on the front side of the detection table (4) to control the movement of the detection table (4). The plane mirror mounting slot (5) is located on the right side of the detection table (4), and a plane mirror is installed on the plane mirror mounting slot (5). 9); The projection-imaging system includes an industrial projector (7), a camera (8), and a plane mirror (9). The industrial projector (7) and the camera (8) are installed on the upper surface of the guide rail frame (3) according to the principle of similar triangles. The workpiece rotation system consists of a workpiece rotating disk (10) and a rotating disk drive module (22). The workpiece rotating disk (10) is installed above the inspection table (4), and the rotating disk drive module (22) is located inside the inspection table (4). The indicator light module includes a standby indicator light (14) and a working indicator light (15). The standby indicator light (14) and the working indicator light (15) are both located on the right side of the protective box (2). The main control system includes a control module (13), a reset button (16), and a host computer (27). The control module (13) is fixed on the upper surface of the guide rail frame (3). The reset button (16) is located on the left side of the working indicator light (15). The host computer (27) is connected to the device through a data cable.

2. The intelligent portable 3D anti-overexposure part defect detection method according to claim 1, characterized in that: The limiting module (17) in the telescopic system of the testing platform consists of a lock head A (18) with an elastic rod A (19), a guide rail A (20), a lock head B (29) with an elastic rod B (30), and a guide rail B (21). The limiting module (17) has a mechanical mechanism with left and right symmetry. The guide rail A (20) has several slots. The elastic rod A (19) is a thin metal strip with elasticity. The lock head A (18) moves in the guide rail A (20). When stationary, the lock head A (18) is embedded in the slot to realize the limiting function. The guide rail B (21) has several slots. The elastic rod B (30) is a thin metal strip with elasticity. The lock head B (29) moves in the guide rail B (21). When stationary, the lock head B (29) is embedded in the slot to realize the limiting function.

3. The intelligent portable 3D anti-overexposure part defect detection method according to claim 1, characterized in that: The rotating disk drive module (22) in the workpiece rotation system consists of a pressure sensor (11), a motor (12), and a coupling (23). The motor (12) is connected to the workpiece rotating disk (10) through the coupling (23). The center of the workpiece rotating disk (10) is on the same line as the output shaft of the motor (12). The pressure sensor (11) is installed below the workpiece rotating disk (10) to detect the pressure value above the workpiece rotating disk (10). The main control system controls the motor (12) to start and stop according to the pressure value. The motor (12) drives the workpiece rotating disk (10) to control the rotation angle of the workpiece under test. The projection-imaging system is used to acquire workpiece view information. The camera (8) and the industrial projector (7) are located in front of the workpiece under test, and the plane mirror ( 9) Located on the side of the workpiece to be tested, the camera (8) acquires the dual-view information of the workpiece to be tested in real time; the main control system is used to control the operation of the entire device and process and analyze image information. The control module (13) in the main control system consists of a data storage module (25), a data transmission module (26), a synchronization trigger module (28), and a main controller (24). The data storage module (25) is used to buffer the received data. The main controller (24) is used for data processing, analysis, judgment, and issuing instructions, thereby controlling the operating status of the entire device. The data transmission module (26) is used to send image information to the host computer. The synchronization trigger module (28) is used to control the camera (8) and the industrial projector (7) to shoot and project synchronously. The reset button (16) controls the main control system to return to the standby state.

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