A method for locating defects in a cylindrical article based on radiographic images

Abstract

The present application relates to a kind of based on ray image's cylinder piece defect positioning method, belong to cylinder piece defect positioning technical field, solve the problems of complex operation, low efficiency of prior art.The method of the present application comprises: the cylinder piece is divided into multiple imaging areas, and each imaging area of the cylinder piece is sequentially single-wall transillumination imaging according to the preset scanning path by imaging device, and the single image of each imaging area is acquired;According to the single image of scanning path, a single image is spliced into an image, and a spliced image is obtained;Identify the defect on the spliced image, and obtain the position of defect on the spliced image;According to the position of defect on the spliced image and the imaging parameter of imaging device, the position of defect on the cylinder piece is acquired.The present application realizes the rapid detection positioning of cylinder piece defect, when the ray transillumination imaging of cylinder piece is carried out, only single image is collected once for each imaging area, and the ray image of all areas of cylinder piece is obtained by splicing, simple operation, high efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of defect positioning of cylindrical parts, and particularly relates to a defect positioning method of cylindrical parts based on a radiographic image. BACKGROUND

[0002] Digital radiographic nondestructive testing technology has been widely used in the industrial field. Through X-ray transmission imaging of a workpiece, the quality of the workpiece can be judged according to the radiographic image, and the workpiece can be nondestructively tested. After confirming the defect position and type on the radiographic image, the actual position of the defect in the three-dimensional space of the workpiece needs to be determined, and repair processing is performed according to the defect position and type.

[0003] The radiographic image is a two-dimensional image, and the defect position on the image and the position in the three-dimensional space of the workpiece are not explicitly corresponding. At present, the method for determining the actual position of the defect through the radiographic image includes manually marking and detecting multiple times to confirm the defect position, or acquiring the spatial information of the workpiece by collecting multiple radiographic images to determine the three-dimensional spatial position of the defect. The method of multiple marking and detection needs to perform multiple marking, detection and other processes, which is complex and low in efficiency, and some marking methods will damage the workpiece. The method of determining the defect position by collecting multiple images needs to take multiple angles at the same position, and the process of determining the three-dimensional position from multiple images has a large amount of calculation. SUMMARY

[0004] In view of the above analysis, the embodiments of the present application aim to provide a defect positioning method of cylindrical parts based on a radiographic image, to solve the technical problems of complex operation and low efficiency in the prior art.

[0005] In one aspect, the embodiments of the present application provide a defect positioning method of cylindrical parts based on a radiographic image, which comprises:

[0006] The cylindrical part is divided into multiple imaging areas, and a single-wall transmission imaging of each imaging area of the cylindrical part is sequentially performed by an imaging device according to a preset scanning path to obtain a single image of each imaging area;

[0007] The single images are spliced into one image according to the scanning path to obtain a spliced image;

[0008] Defects on the spliced image are identified, and the positions of the defects on the spliced image are obtained;

[0009] The positions of the defects on the cylindrical part are obtained according to the positions of the defects on the spliced image.

[0010] Further improvement based on the above method, when single-wall transmission imaging is performed, the detector of the imaging device is located on the central axis of the cylindrical member, the ray source of the imaging device is located on the outside of the cylindrical member, and the central ray beam of the ray source coincides with the central axis of the detector.

[0011] Further improvement based on the above method, the acquisition of the position of the defect on the cylindrical member according to the position of the defect on the spliced image comprises:

[0012] Defining the single image where the defect is located as a defect image, and the imaging area where the defect is located as a target area;

[0013] Acquiring the position of the defect on the defect image and the position of the target area on the cylindrical member according to the position of the defect on the spliced image;

[0014] Acquiring the position of the defect on the target area according to the position of the defect on the defect image;

[0015] Acquiring the position of the defect on the cylindrical member according to the position of the defect on the target area and the position of the target area on the cylindrical member.

[0016] Further improvement based on the above method, the acquisition of the position of the defect on the defect image according to the position of the defect on the spliced image comprises:

[0017] The number of horizontal pixels of the detector is w and the number of vertical pixels is h;

[0018] Defining the coordinates of the position of the defect on the spliced image as (x, y); and the coordinates of the position of the defect on the defect image as (x', y');

[0019] Let x' be equal to x modulo w and y' be equal to y modulo h, so as to obtain the coordinates (x', y') of the position of the defect on the defect image.

[0020] Further improvement based on the above method, the acquisition of the position of the defect on the target area according to the position of the defect on the defect image comprises:

[0021] Defining the coordinates of the position of the defect on the target area as (θ, H I ); θ is an angular coordinate and H I is a height coordinate;

[0022] According to the two-dimensional coordinates (x', y') of the position of the defect on the defect image and the pixel parameters of the detector, the horizontal distance W Dand vertical distance H D ;

[0023] Based on the projection principle, according to the horizontal distance W between the defect and the center of the detector D and vertical distance H D Calculate the coordinates (θ, H) of the location of the defect in the target area. I ).

[0024] Based on a further improvement of the above method, the horizontal distance W between the defect and the center of the detector is calculated. D and vertical distance H D The formula is:

[0025] W D = (x' - w / 2) * s;

[0026] H D = (y'-h / 2)*s;

[0027] In the formula, w is the number of pixels in the horizontal direction of the detector, h is the number of pixels in the vertical direction of the detector, and s is the size of a single pixel of the detector.

[0028] Based on a further improvement of the above method, the formula for calculating the coordinates θ of the defect's position in the target area is as follows:

[0029]

[0030] a=(F 2 +W D 2 )*R0 2 ;

[0031] b = -2W D 2 *L*R;

[0032] c = W D 2 *L 2 +F 2 *R 2 ;

[0033] In the formula, a, b, and c are parameters, L is the distance between the X-ray source and the central axis of the cylindrical component, and F is the distance between the X-ray source and the center of the detector.

[0034] Based on a further improvement of the above method, the coordinates H of the location of the defect in the target area are calculated. I The formula is:

[0035]

[0036] Further improvement based on the above method, the method further comprises:

[0037] Before single-wall transmission imaging, the laser pointer is fixed on one side of the ray source of the imaging device, and the laser emitted by the laser pointer is irradiated on the same position on the cylinder as the central ray beam of the ray source of the imaging device;

[0038] According to the position of the defect on the spliced image and the imaging parameters of the imaging device, the position of the defect image on the spliced image is obtained;

[0039] According to the position of the defect on the spliced image and the imaging parameters of the imaging device, the position of the defect image on the spliced image is obtained;

[0040] According to the position of the defect on the target area and the position of the imaging device for obtaining the defect image, the indication position is obtained;

[0041] The imaging device is moved to the indication position, so that the laser emitted by the laser pointer marks the defect on the cylinder.

[0042] Further improvement based on the above method, according to the position of the defect on the spliced image and the imaging parameters of the imaging device, the position of the defect image on the spliced image is obtained, comprising:

[0043] The position coordinates (c, r) of the defect image on the spliced image are defined; c is the number of rows, and r is the number of columns;

[0044] The number of rows c of the defect image on the spliced image is equal to x divided by w, and the number of columns r is equal to y divided by h, so as to obtain the position (c, r) of the defect image on the spliced image. Compared with the prior art, the present application can realize at least one of the following beneficial effects:

[0045] 1. The present application provides a cylinder defect positioning method based on ray image, which realizes rapid detection and positioning of cylinder defects. When performing ray transmission imaging on the cylinder, only one single image is collected for an imaging area of the cylinder, and the ray image of the whole imaging area of the cylinder, i.e. the spliced image, is obtained by splicing, and then the position of the defect on the cylinder (three-dimensional space) is determined according to the position of the defect on the spliced image (two-dimensional plane), without collecting multiple images for the same position and repeated marking detection operations, which is simple and efficient and will not cause damage to the workpiece.

[0046] 2、The laser pointer is arranged in the application for marking the defect position on the cylindrical part, and the rapid visual positioning of the defect is realized.

[0047] The above technical solutions can be combined with each other in the application to realize more preferred combination solutions. Other features and advantages of the application will be described in the subsequent description, and some advantages will become apparent from the description, or will be understood by implementing the application. The purposes and other advantages of the application can be realized and obtained from the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and serve to explain the principles of the application.

[0049] Figure 1 A flow chart of the cylindrical part defect positioning method based on the radiographic image according to an embodiment of the application;

[0050] Figure 2 A schematic diagram of the projection of the cylindrical part, the radiographic source, the detector and the transmission point (defect) on the horizontal plane according to an embodiment of the application;

[0051] Figure 3 A schematic diagram of the projection of the radiographic source, the detector and the transmission point (defect) on the vertical plane according to an embodiment of the application

[0052] Figure 4 A schematic diagram of the projection of the radiographic source, the detector and the transmission point (defect) on the horizontal plane according to an embodiment of the application. DETAILED DESCRIPTION

[0053] The preferred embodiments of the application will be described in detail below with reference to the accompanying drawings, wherein the drawings constitute a part of this application and are used to explain the principles of the embodiments of the application, but are not used to limit the scope of the application.

[0054] One specific embodiment of the application discloses a kind of cylindrical part defect positioning method based on radiographic image, as shown in Figure 1 The method comprises:

[0055] Step 1, the cylindrical part is divided into a plurality of imaging areas, and each imaging area of the cylindrical part is sequentially subjected to single-wall transmission imaging by the imaging device according to a preset scanning path, so as to obtain a single image of each imaging area;

[0056] Step 2, the single images are spliced into one image according to the scanning path, so as to obtain a spliced image;

[0057] Step 3, defects on the spliced image are identified, and positions of the defects on the spliced image are obtained;

[0058] Step 4, positions of the defects on the cylindrical part are obtained according to the positions of the defects on the spliced image.

[0059] Compared with the prior art, the embodiment of the present application provides a cylindrical part defect positioning method based on a ray image, realizes rapid detection and positioning of cylindrical part defects, and only collects a single image for one imaging area of the cylindrical part when performing ray transmission imaging on the cylindrical part, obtains ray images of all imaging areas of the cylindrical part, i.e., a spliced image, through splicing, and then determines the position (three-dimensional space position) of the defect on the cylindrical part according to the position (two-dimensional plane position) of the defect on the spliced image, without the need for collecting multiple images for the same position and repeated marking detection operations, so that the operation is simple, the efficiency is high, and the workpiece is not damaged.

[0060] It should be noted that the imaging device includes a detector and a ray source, the ray source is responsible for emitting rays penetrating the measured object in the imaging device, and the detector captures the penetrated rays and converts them into images.

[0061] Step 1, the cylindrical part is divided into a plurality of imaging areas, and each imaging area of the cylindrical part is sequentially subjected to single-wall transmission imaging by the imaging device according to a preset scanning path, so as to obtain a single image of each imaging area.

[0062] Specifically, when performing single-wall transmission imaging, the detector of the imaging device is located on the central axis of the cylindrical part, the ray source of the imaging device is located on the outside of the cylindrical part, and the central ray beam of the ray source coincides with the central axis of the detector.

[0063] In implementation, the cylindrical part is divided into a plurality of imaging areas according to the imaging area of the imaging device, and then the scanning path is planned, so that the imaging device can completely scan each imaging area of the cylindrical part according to the planned scanning path.

[0064] The imaging area refers to the area of the region that can be effectively imaged by the imaging device, i.e., the area covered by the finally generated image.

[0065] The motion direction between each scanning point on the scanning path includes rotation of the cylinder axis with the central axis as the rotation axis and up-down translation of the imaging device in the vertical direction. Specifically, the trajectory of the scanning path can be that the imaging device performs transmission imaging on each height of the imaging region in turn from one end (upper end or lower end) of the cylinder, and after completing transmission imaging of one height, the imaging device moves to the next height until transmission imaging of the other end of the cylinder is completed. Wherein, after the imaging device moves to the preset height, a single image of the imaging region corresponding to the initial position is first obtained by transmission, and then the cylinder or the imaging device is rotated by a preset angle to perform transmission imaging on the adjacent imaging region in turn until the transmission imaging of each imaging region at the height is completed.

[0066] Step 2, splicing the single images into one image according to the scanning path to obtain a spliced image.

[0067] Wherein, the scanning path refers to the path along which the ray source and the detector move along a specific trajectory to obtain the internal information of the measured object during the imaging process. Therefore, splicing the single images into one image according to the scanning path can obtain the complete ray image of the cylinder.

[0068] Step 3, identifying the defect on the spliced image and obtaining the position of the defect on the spliced image.

[0069] In implementation, the position of the defect on the spliced image can be determined by manual determination or intelligent determination (for example, by an artificial intelligence model). When the defect is determined by manual determination, the inspector manually selects the defect position in the image, and then the defect position is input into the subsequent calculation process; when the defect position is determined by intelligent determination, the software automatically determines the defect position and inputs it into the subsequent calculation process.

[0070] Step 4, obtaining the position of the defect on the cylinder according to the position of the defect on the spliced image, comprising:

[0071] Defining the single image where the defect is located as a defect image, and defining the imaging region where the defect is located as a target region;

[0072] Obtaining the position of the defect on the defect image and the position of the target region on the cylinder according to the position of the defect on the spliced image;

[0073] Obtaining the position of the defect on the target region according to the position of the defect on the defect image;

[0074] Obtaining the position of the defect on the cylinder according to the position of the defect on the target region and the position of the target region on the cylinder.

[0075] Specifically, the position of the defect on the defect image is obtained according to the position of the defect on the spliced image, comprising:

[0076] The number of horizontal pixels of the detector is w and the number of vertical pixels is h;

[0077] The coordinates of the position of the defect on the spliced image are defined as (x, y); the coordinates of the position of the defect on the defect image are defined as (x', y');

[0078] x' is equal to x mod w, and y' is equal to y mod h, so that the coordinates (x', y') of the position of the defect on the defect image are obtained.

[0079] Specifically, the position of the defect on the target area is obtained according to the position of the defect on the defect image, comprising:

[0080] The coordinates of the position of the defect on the target area are defined as (θ, H I ); θ is an angle coordinate, and H I is a height coordinate;

[0081] The horizontal distance W D and the vertical distance H D of the defect from the center of the detector are obtained according to the two-dimensional coordinates (x', y') of the position of the defect on the defect image and the pixel parameters of the detector.

[0082] Based on the projection principle, the coordinates (θ, H I ) of the position of the defect on the target area are calculated according to the horizontal distance W D and the vertical distance H D of the defect from the center of the detector.

[0083] The formula for calculating the horizontal distance W D and the vertical distance H D of the defect from the center of the detector is:

[0084] W D = (x'-w / 2)*s;

[0085] H D = (y'-h / 2)*s;

[0086] In the formula, w is the number of horizontal pixels of the detector, h is the number of vertical pixels of the detector, and s is the size of a single pixel of the detector.

[0087] In the calculation of the horizontal distance W D and the vertical distance H D of the center of the detector,After that, the position of the defect (transmission point) is calculated, and the calculation principle is as shown in Figures 2 to 4 .

[0088] The cylinder and the ray source, the detector and the transmission point (defect) are projected on the horizontal plane, as shown in Figure 2 . According to the geometric relationship shown in Figure 2 , the formula for calculating the coordinate θ of the position of the defect on the target area is obtained:

[0089]

[0090] a = (F 2 +W D 2 )*R0 2 ;

[0091] b = -2W D 2 *L*R;

[0092] c = W D 2 *L 2 +F 2 *R 2 ;

[0093] In the formula, a, b, and c are parameters, L is the distance between the ray source and the central axis of the cylinder, and F is the distance between the ray source and the center of the detector.

[0094] Wherein, the distance L between the ray source and the central axis of the cylinder, and the distance F between the ray source and the center of the detector are known parameters, which are set according to actual testing requirements before ray transmission, and then the detector and the ray source are moved to the corresponding positions.

[0095] The position of the ray source is defined as point S, the position of the ray passing through the cylinder is defined as point I, and the point where the ray is irradiated on the detector is defined as point D. The projections of points I and D on the horizontal plane passing through point S are points I' and D' respectively, and the relationship between the points in the vertical plane is as shown in Figure 3 . In the projected horizontal plane, the distance relationship is as shown in Figure 4 . According to the geometric relationship in Figure 3 and Figure 4 , the formula for calculating the coordinate H I of the position of the defect on the target area is obtained:

[0096]

[0097] In one embodiment, the method further comprises:

[0098] Step 0, before single-wall transmission imaging, fixing a laser pointer on one side of a ray source of the imaging device, and making the laser emitted by the laser pointer irradiate on the same position on the cylinder as the central ray beam of the ray source of the imaging device;

[0099] Step 5, according to the position of the defect on the spliced image and the imaging parameters of the imaging device, obtaining the position of the defect image on the spliced image;

[0100] Step 6, according to the position of the defect image on the spliced image and the scanning path, determining the position of the imaging device when obtaining the defect image;

[0101] Step 7, according to the position of the defect on the target area and the position of the imaging device when obtaining the defect image, obtaining an indication position;

[0102] Step 8, moving the imaging device to the indication position, so that the defect is marked on the cylinder by the laser emitted by the laser pointer.

[0103] Compared with the prior art, in the embodiment of the present application, the laser pointer for marking the defect position on the cylinder is arranged, and the rapid visual positioning of the defect is realized. Specifically, the position of the imaging device when obtaining the defect image can be calculated according to the position of the defect on the spliced image, and then the indication position is obtained. Since the position irradiated by the laser emitted by the laser pointer on the cylinder is the same as the position irradiated by the central ray beam of the ray source of the imaging device on the cylinder, when the imaging device is moved to the indication position, the position marked by the laser on the cylinder is the position through which the central ray beam of the ray source passes during transmission imaging, that is, the defect position, so that the defect is marked on the cylinder by the laser emitted by the laser pointer.

[0104] Specifically, according to the position of the defect on the spliced image and the imaging parameters of the imaging device, the position of the defect image on the spliced image is obtained, comprising:

[0105] defining the position coordinates (c, r) of the defect image on the spliced image; c is the number of rows, and r is the number of columns;

[0106] making the number of rows c of the defect image on the spliced image equal to x divided by w, and the number of columns r equal to y divided by h, so as to obtain the position (c, r) of the defect image on the spliced image.

[0107] After the position (c, r) of the defect image on the spliced image is obtained, the position of the imaging device when obtaining the defect image is determined in combination with the scanning path.

[0108] In implementation, the position of the imaging device is defined as a three-dimensional coordinate (r, φ, z) in the cylindrical coordinate system, r is a radial distance coordinate, φ is an angle coordinate, and z is a height coordinate. In defect detection, the radial distance coordinate r = r0 is fixed, i.e., the distance between the laser source and the cylinder wall is fixed. Assuming that the position coordinate of the imaging device when acquiring the defect image is (r0, φ0, z0), the angle coordinate and the height coordinate of the imaging device when acquiring the defect image are added to the angle coordinate and the height coordinate of the defect on the target area, respectively, to obtain the coordinate of the indicated position, i.e., the coordinate of the indicated position is (r0, φ0+ θ, z0+ H I ).

[0109] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. The computer readable storage medium includes a magnetic disk, an optical disk, a read-only memory, a random access memory, etc.

[0110] The above description is only the preferred embodiment of the present application, and the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed by the present application can be easily conceived by those skilled in the art, and should be covered within the protection scope of the present application.

Claims

1. A method for locating defects in a cylindrical object based on radiographic images, characterized in that, The method comprises: dividing the cylindrical member into a plurality of imaging areas according to the imaging area of the imaging device, sequentially performing single-wall transmission imaging on each imaging area of the cylindrical member according to a preset scanning path by the imaging device to obtain a single image of each imaging area, wherein the movement direction between each scanning point on the scanning path comprises rotation of the cylindrical member around the central axis as the rotation axis and up-down translation of the imaging device in the vertical direction; stitching the single images into one image according to the scanning path to obtain a stitched image; identifying defects on the stitched image and obtaining the positions of the defects on the stitched image; obtaining the positions of the defects on the cylindrical member according to the positions of the defects on the stitched image; obtaining the positions of the defects on the cylindrical member according to the positions of the defects on the stitched image, comprising: defining the single image where the defect is located as a defect image and defining the imaging area where the defect is located as a target area; obtaining the position of the defect on the defect image and the position of the target area on the cylindrical member according to the position of the defect on the stitched image; obtaining the position of the defect on the target area according to the position of the defect on the defect image; obtaining the position of the defect on the cylindrical member according to the position of the defect on the target area and the position of the target area on the cylindrical member; obtaining the position of the defect on the defect image according to the position of the defect on the stitched image, comprising: the number of horizontal pixels of the detector is w and the number of vertical pixels is h; coordinates defining the position of the defect on the stitched image are ; and coordinates defining the position of the defect on the defect image are ; making equal to x mod w, equal to y mod h, thereby obtaining the coordinates of the position of the defect on the defect image ; obtaining the position of the defect on the target area according to the position of the defect on the defect image, comprising: coordinates defining the position of said defect on said target area are defined as ; are angular coordinates, are height coordinates; a two-dimensional coordinate of a position of the defect on the defect image and the detector pixel parameter obtains a horizontal distance of the defect from the detector center and a vertical distance ; based on the projection principle, the position of the defect on the target area is calculated according to the horizontal distance of the defect from the center of the detector and the vertical distance of the defect from the center of the detector ; calculating a horizontal distance of the defect from the center of the detector and a vertical distance The formula is: ； ； wherein h is the number of pixels in the vertical direction of the detector, is the size of a single pixel of the detector.

2. The method of claim 1, wherein, when performing single-wall transmission imaging, the detector of the imaging device is located on the central axis of the cylindrical member, the ray source of the imaging device is located on the outside of the cylindrical member, and the central ray bundle of the ray source coincides with the central axis of the detector.

3. The method of claim 1, wherein, calculating coordinates of a position of the defect on the target area The formula is: ； ； ； ； wherein , , L is the distance between the source and the central axis of the cylinder, F is the distance between the source and the detector center.

4. The method of claim 1, wherein, calculating coordinates of a position of the defect on the target area The formula is: 。 5. The method of claim 1, wherein, The method further comprises: before performing single-wall transmission imaging, fixing a laser pointer on one side of the ray source of the imaging device and making the laser emitted by the laser pointer irradiate on the cylindrical member at the same position as the central ray bundle of the ray source of the imaging device; obtaining the position of the defect image on the stitched image according to the position of the defect on the stitched image and the imaging parameters of the imaging device; determining the position of the imaging device when obtaining the defect image according to the position of the defect image on the stitched image and the scanning path; obtaining an indication position according to the position of the defect on the target area and the position of the imaging device when obtaining the defect image; moving the imaging device to the indication position, so that the defect on the cylindrical member is marked by the laser emitted by the laser pointer.

6. The method of claim 5, wherein, obtaining the position of the defect image on the stitched image according to the position of the defect on the stitched image and the imaging parameters of the imaging device, comprising: defining position coordinates of the defect image on the stitched image ; c is the number of rows and r is the number of columns. causing the defect image to be located on the stitched image in a row number c equal to x divided by w rounded down and a column number r equal to y divided by h rounded down .

Images