Three-dimensional display method and system for XRF element scanning result

Abstract

The invention discloses a three-dimensional display method and system for XRF element scanning results. The method comprises the following steps: 1) performing three-dimensional scanning on a target object by using a three-dimensional XRF scanning system at a currently selected angle, and recording spectral data and three-dimensional position information of each scanning point; 2) calculating the relative content of each element distribution in a scanning position area corresponding to the target object according to the spectral data of each scanning point; according to the three-dimensional position information of each scanning point, generating a three-dimensional point cloud conforming to the surface contour of the target object at the current selected angle; 3) mapping each element existing in the target object calculated at the current angle to an RGB color space, and generating a three-dimensional element distribution diagram with colors; 4) changing the angle and repeating the steps 1-3) once; and 5) splicing the colored three-dimensional element distribution diagrams corresponding to the plurality of different angles to obtain a complete colored three-dimensional element distribution diagram of the target object. According to the invention, scanning blurring and distortion are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of X-ray fluorescence (XRF) scanning imaging, and relates to a three-dimensional display method and system for XRF element scanning results. Background Art

[0002] Currently, the known display methods of X-ray fluorescence scanning results are all two-dimensional displays. The X-ray fluorescence imaging system scans the surface of the object and records the element spectrum information of each scanning point. Through the spectrum analysis algorithm, the relative content of each element at each scanning point is obtained. Its content is marked as the pixel value of the element distribution image, thereby generating an element distribution image of the object surface.

[0003] The most similar solution to the present invention is the display method of element scanning results of the micro-area X-ray fluorescence imaging system of BRUKER. In the process of scanning an object, the system only performs a two-dimensional scan on the object, matches the element content obtained by the scan with the two-dimensional position coordinates of the scanning point, and converts the two-dimensional position coordinates into pixel coordinates to generate a two-dimensional image of element distribution.

[0004] The existing X-ray fluorescence imaging scanning results are only displayed in two dimensions in the form of color images. This results in the three-dimensional position information being converted into two-dimensional pixel information when scanning a three-dimensional sample to be tested, causing blur or even distortion of the element distribution image. When performing multi-view stereoscopic scanning of an object, the two-dimensional distribution image can only restore the element distribution of the object from one perspective, causing overlap and interference of distribution images at some angles.

[0005] In terms of point cloud stitching, existing point cloud stitching technologies are mostly guided by point cloud feature contours. However, in the field of X-ray fluorescence scanning imaging, it is difficult to accurately stitch three-dimensional point clouds in different coordinate systems only through feature contours. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a three-dimensional display method and system for XRF element scanning results. The present invention analyzes the three-dimensional interactive display of X-ray fluorescence (XRF) scanning results, combines the spectral data obtained by the analysis with the three-dimensional point cloud data of the scanned object, and not only displays the element content information of the scanning point, but also displays the three-dimensional position information of the scanning point. Through the fusion and splicing of the point cloud, the distribution of elements of irregularly scanned samples in three-dimensional space can be accurately restored. Displaying the scanning results in the form of a three-dimensional point cloud can realize three-dimensional rotation and scaling of the scanning results. Users can more conveniently obtain the three-dimensional element distribution information of interest through interactive display.

[0007] This method uses a three-dimensional scanning method to perform X-ray fluorescence scanning, and each scanning point records the spectral information and three-dimensional position information obtained by the scan. The scanning results are displayed in the form of a three-dimensional point cloud, which can simultaneously display the three-dimensional contour and surface element distribution of the object. Through the element-guided point cloud stitching algorithm, the scanning results of multiple angles can be stitched together to form a 360° annular element distribution image of the object. Displaying the element scanning results of the object surface in the form of a three-dimensional point cloud allows users to freely rotate and scale the scanning results, and achieve accurate display of the scanning results at various angles.

[0008] The technical solution of the present invention is:

[0009] A three-dimensional display method for XRF element scanning results, the steps comprising:

[0010] 1) Use the 3D XRF scanning system to perform a 3D scan of the target object at the currently selected angle, and record the spectral data and 3D position information of each scanning point;

[0011] 2) Calculate the relative content of each element distribution in the target object corresponding to the scanning position area based on the spectral data of each scanning point; Generate a three-dimensional point cloud that conforms to the surface contour of the target object at the currently selected angle based on the recorded three-dimensional position information of each scanning point;

[0012] 3) Mapping each element existing in the target object calculated at the currently selected angle to the RGB color space; wherein,

[0013] Assign color information to the element content, different elements correspond to different colors, and determine the brightness of the color corresponding to the element according to the element content; then determine the color information corresponding to each point in the three-dimensional point cloud according to the three-dimensional position information and color information of the scanning point, and generate a three-dimensional element distribution map with color;

[0014] 4) Repeat steps 1 to 3) once with changing the angle to generate a plurality of three-dimensional element distribution maps with colors corresponding to different angles;

[0015] 5) The colored three-dimensional element distribution maps corresponding to multiple different angles are spliced ​​to obtain a complete colored three-dimensional element distribution map of the target object.

[0016] Furthermore, the method for splicing the colored three-dimensional element distribution map is as follows: for each color channel in the colored three-dimensional element distribution map at each selected angle, a set of feature points is extracted based on the color gradient; the feature points corresponding to each color channel at the i-th selected angle are combined with the contour features of the three-dimensional point cloud corresponding to the i-th selected angle to match the feature points extracted from the adjacent three-dimensional element distribution map; and then the colored three-dimensional element distribution map is spliced ​​according to the feature matching results and the overlapping point clouds are removed.

[0017] Furthermore, the spectral data and three-dimensional position information of each scanning point are stored in the same record of the same point cloud file; and the element content information calculated based on the spectral data of each scanning point is stored in the corresponding record of the point cloud file.

[0018] Furthermore, the complete colored three-dimensional element distribution map of the target object is a 360° annular element distribution map.

[0019] A three-dimensional display system for XRF element scanning results, characterized in that it includes a three-dimensional XRF scanning system and a data processing unit; wherein,

[0020] The three-dimensional XRF scanning system is used to perform three-dimensional scanning on the target object at the currently selected angle, and send the spectrum data and three-dimensional position information of each scanning point to the data processing unit;

[0021] The data processing unit is used to calculate the relative content of each element distribution in the corresponding scanning position area of ​​the target object according to the spectral data of each scanning point; generate a three-dimensional point cloud that conforms to the surface contour of the target object at the currently selected angle according to the recorded three-dimensional position information of each scanning point; map each element existing in the target object calculated at the currently selected angle to the RGB color space; wherein, color information is given to the element content, different elements correspond to different colors, and the brightness of the color corresponding to the element is determined according to the element content; then, according to the three-dimensional position information and color information of the scanning point, the color information corresponding to each point in the three-dimensional point cloud is determined to generate a colored three-dimensional element distribution map; then, the colored three-dimensional element distribution maps corresponding to multiple different angles are spliced ​​to obtain a complete colored three-dimensional element distribution map of the target object.

[0022] The advantages of the present invention are as follows:

[0023] The present invention uses a three-dimensional point cloud to accurately display the distribution of surface elements of an object in three-dimensional space, so that the display of XRF scanning results breaks through the constraints of two-dimensional images and avoids the blur and distortion caused by the two-dimensional image display of three-dimensional scanning results. The XRF scanning results are displayed in the form of a three-dimensional point cloud, and at the same time, a 360° annular scanning of a three-dimensional object is possible. The point cloud splicing technology guided by the element distribution can realize the generation of a 360° annular element distribution map in space. In addition, the use of a three-dimensional point cloud to display the XRF scanning results can facilitate users to rotate and scale the scanning results and obtain the three-dimensional distribution of elements from various angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of generating a three-dimensional element distribution image of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention but not to limit the scope of the present invention.

[0026] Figure 1 It is a specific flow chart for generating a complete three-dimensional element distribution image of the object surface, and its steps include:

[0027] 1) First, a 3D XRF scanning system is used to perform a 3D scan of the target object, and the spectral data and 3D position information of each scanning point are collected during the scanning process.

[0028] 2) During the data storage process, the spectral data and position information are stored separately in a unified arrangement. After that, the spectral data of each scanning point is used for element analysis to calculate the relative content of each element distribution at each scanning point. The position information of each scanning point is used to generate an ordered three-dimensional point cloud that conforms to the surface contour of the target object.

[0029] 3) Because the spectral data and position information are given a unified retrieval method during the storage process, the element content information and position information obtained by spectral analysis are stored in the same point cloud file. For each existing element, the element content of each point is mapped to the RGB color space, and the element content is given color information. Different elements correspond to different colors, and the content of the same element corresponds to the lightness and darkness of the same color. After that, the color information of each scanning point is matched one by one with the position information of the three-dimensional point cloud, and a three-dimensional element distribution map with color is generated in the form of a three-dimensional point cloud.

[0030] 4) Multiple scans at multiple angles generate multiple 3D element distribution maps. Each 3D element distribution map contains the distribution characteristics of each element. The type and content of the element correspond to the color and brightness of the 3D point cloud respectively. For a single color channel, based on the change in color gradient, the area with high color change can be found as the feature point (the high color change area of ​​a single channel is the area with high image pixel value change in the channel, that is, the area with pixel value gradient change greater than the set ratio. The ratio parameter is adjustable rather than a fixed value). At the same time, the distribution of different element types can extract the feature points of different color channels and record the 3D coordinates of the feature points, so as to obtain the 3D coordinates (x, y, z) of three groups of feature points of the three RGB channels. These element distribution characteristics are combined with the contour characteristics of the 3D point cloud to more accurately realize the feature matching of point clouds at different angles, identify and remove the overlapping point cloud parts after matching, so as to splice multiple 3D element distribution maps at different angles into a complete 3D element distribution map of the target object surface.

[0031] The method for feature matching based on the contour features of the 3D point cloud is:

[0032] First, extract the feature points of each color channel for the i-th angle and record the XYZ coordinates of the feature points to obtain the XYZ coordinates of the three groups of feature points corresponding to the three RGB channels. Secondly, for the i-th angle, use the known three-dimensional feature extraction algorithm to obtain the contour features of the three-dimensional point cloud corresponding to the i-th angle as the fourth group of feature points.

[0033] The four groups of feature points of the two three-dimensional element distribution maps are input together into a feature matching function, which is a well-known feature matching method, to obtain a matching result.

[0034] Feature matching is to match the four groups of feature points of the i-th angle with the four groups of feature points of the adjacent angles, such as the i+1th or i-1th angle, that is, to determine which feature points of the two angles are the same point in the base coordinate system. For example, if the feature points extracted from the i-th angle are points A and B, and the feature points of the i+1th angle are points A and C, then after feature matching, it can be determined that point A is a repeated feature point in the two angles, and based on this, the colored three-dimensional element distribution map is then spliced ​​according to the matching results.

[0035] Although the specific embodiments of the present invention are disclosed for the purpose of illustration, the purpose is to help understand the content of the present invention and implement it accordingly, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the best embodiment, and the scope of the present invention is subject to the scope defined in the claims.

Claims

1. A three-dimensional display method for XRF element scanning results, the steps comprising: 1) Use the 3D XRF scanning system to perform a 3D scan of the target object at the currently selected angle, and record the spectral data and 3D position information of each scanning point; 2) Calculate the relative content of each element distribution in the target object corresponding to the scanning position area based on the spectral data of each scanning point; Generate a three-dimensional point cloud that conforms to the surface contour of the target object at the currently selected angle based on the recorded three-dimensional position information of each scanning point; 3) Mapping each element existing in the target object calculated at the currently selected angle to the RGB color space; wherein, color information is assigned to the element content, different elements correspond to different colors, and the brightness of the color corresponding to the element is determined according to the element content; then, according to the three-dimensional position information and color information of the scanning point, the color information corresponding to each point in the three-dimensional point cloud is determined to generate a three-dimensional element distribution map with color; 4) Repeat steps 1 to 3) once with changing the angle to generate a plurality of three-dimensional element distribution maps with colors corresponding to different angles; 5) The colored three-dimensional element distribution maps corresponding to multiple different angles are spliced ​​to obtain a complete colored three-dimensional element distribution map of the target object.

2. The method according to claim 1, characterized in that The method for splicing colored three-dimensional element distribution maps is as follows: for each color channel in the colored three-dimensional element distribution map at each selected angle, a set of feature points is extracted based on the color gradient; the feature points corresponding to each color channel at the i-th selected angle are combined with the contour features of the three-dimensional point cloud corresponding to the i-th selected angle to match the feature points extracted from the adjacent three-dimensional element distribution maps; and then the colored three-dimensional element distribution maps are spliced ​​according to the feature matching results and the overlapping point clouds are removed.

3. The method according to claim 1 or 2, characterized in that: The spectral data and three-dimensional position information of each scanning point are stored in the same record of the same point cloud file; and the element content information calculated according to the spectral data of each scanning point is stored in the corresponding record of the point cloud file.

4. The method according to claim 1, 2 or 3, characterized in that: The complete three-dimensional element distribution map with color of the target object is a 360° annular element distribution map.

5. A three-dimensional display system for XRF element scanning results, characterized in that: It includes a three-dimensional XRF scanning system and a data processing unit; wherein, The three-dimensional XRF scanning system is used to perform three-dimensional scanning on the target object at the currently selected angle, and send the spectrum data and three-dimensional position information of each scanning point to the data processing unit; The data processing unit is used to calculate the relative content of each element distribution in the corresponding scanning position area of ​​the target object according to the spectral data of each scanning point; generate a three-dimensional point cloud that conforms to the surface contour of the target object at the currently selected angle according to the recorded three-dimensional position information of each scanning point; map each element existing in the target object calculated at the currently selected angle to the RGB color space; wherein, color information is given to the element content, different elements correspond to different colors, and the brightness of the color corresponding to the element is determined according to the element content; then, according to the three-dimensional position information and color information of the scanning point, the color information corresponding to each point in the three-dimensional point cloud is determined to generate a colored three-dimensional element distribution map; then, the colored three-dimensional element distribution maps corresponding to multiple different angles are spliced ​​to obtain a complete colored three-dimensional element distribution map of the target object.

6. The system according to claim 5, characterized in that The method for the data processing unit to splice the colored three-dimensional element distribution map is as follows: for each color channel in the colored three-dimensional element distribution map at each selected angle, a group of feature points are extracted based on the color gradient; the feature points corresponding to each color channel at the i-th selected angle are combined with the contour features of the three-dimensional point cloud corresponding to the i-th selected angle to match the feature points extracted from the adjacent three-dimensional element distribution map; and then the colored three-dimensional element distribution map is spliced ​​according to the feature matching results and the overlapping point clouds are removed.

7. The system according to claim 5 or 6, characterized in that: The data processing unit stores the spectral data and three-dimensional position information of each scanning point in the same record of the same point cloud file; and stores the element content information calculated according to the spectral data of each scanning point in the corresponding record of the point cloud file.

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