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

Abstract

The present invention discloses a three-dimensional display method and system for XRF element scanning results. The method is as follows: 1) Use a three-dimensional XRF scanning system to perform three-dimensional scanning on a target object at the currently selected angle, and record the spectral data and three-dimensional position information of each scanning point; 2) Calculate the relative content of the distribution of each element in the scanning position area corresponding to 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 three-dimensional position information of each scanning point; 3) Map each element existing in the target object calculated at the current angle to the RGB color space to generate a three-dimensional element distribution map with colors; 4) Repeat steps 1 to 3) after changing the angle; 5) Stitch the three-dimensional element distribution maps with colors corresponding to multiple different angles to obtain a complete three-dimensional element distribution map with colors of the target object. The present invention avoids scanning blurring and distortion.

Description

Technical Field

[0001] The present 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 for X-ray fluorescence scanning results are all two-dimensional displays. The X-ray fluorescence imaging system scans the surface of an object and records the elemental spectral information of each scanning point. Through spectral analysis algorithms, the relative content of each element at each scanning point is obtained. The content is marked as the pixel value of the elemental distribution image, and thus an elemental distribution image of the object surface is generated.

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

[0004] The existing display methods for X-ray fluorescence imaging scanning results are only two-dimensional displays in the form of color images. This results in the conversion of three-dimensional position information into two-dimensional pixel information when scanning a three-dimensional sample to be measured, causing blurring and even distortion of the elemental distribution image. When performing multi-view stereo scanning on an object, the two-dimensional distribution image can only restore the elemental distribution of the object from one view, causing overlap and interference of the distribution images at some angles.

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

[0006] Aiming at 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 analyzed spectral data with the three-dimensional point cloud data of the scanned object, not only displays the elemental content information of the scanning points, but also displays the three-dimensional position information of the scanning points. Through the fusion and stitching of the point clouds, the elemental distribution of the irregular scanned sample in three-dimensional space is accurately restored. The scanning results are displayed in the form of a three-dimensional point cloud, enabling three-dimensional rotation and scaling of the scanning results. Users can more conveniently obtain the three-dimensional elemental distribution information of interest through interactive display.

[0007] This method uses three-dimensional scanning for X-ray fluorescence scanning, and the spectral information and three-dimensional position information obtained from each scanning point are recorded. The scanning results are displayed in the form of a three-dimensional point cloud, which can simultaneously display the three-dimensional contour of the object and the surface element distribution. Through an element-guided point cloud stitching algorithm, the scanning results from multiple angles can be stitched together to form a 360° annular element distribution image of the object. Displaying the element scanning results on the surface of the object in the form of a three-dimensional point cloud allows users to freely rotate and zoom the scanning results, achieving an accurate display of the scanning results from all angles.

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

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

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

[0011] 2) Calculate the relative content of the distribution of each element in the scanning position area corresponding to 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;

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

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

[0014] 4) Change the angle and repeat steps 1 to 3) once to generate multiple three-dimensional element distribution maps with colors corresponding to different angles;

[0015] 5) Stitch the three-dimensional element distribution maps with colors corresponding to multiple different angles to obtain a complete three-dimensional element distribution map with colors of the target object.

[0016] Furthermore, the method for stitching the three-dimensional element distribution map with colors is as follows: for each color channel in the three-dimensional element distribution map with colors at each selected angle, extract a set of feature points based on the color gradient; use the feature points corresponding to each color channel at the i-th selected angle in combination 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; then stitch the three-dimensional element distribution map with colors according to the feature matching result and remove the overlapping point clouds.

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

[0018] Further, the complete three-dimensional elemental distribution map with color of the target object is a 360° annular elemental distribution map.

[0019] A three-dimensional display system for XRF elemental scanning results, characterized by comprising 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 spectral 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 the distribution of each element 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 elemental content, different elements correspond to different colors, and the brightness of the color corresponding to the element is determined according to the content of the element; then, according to the three-dimensional position information and color information of the scanning point, determine the color information corresponding to each point in the three-dimensional point cloud, and generate a three-dimensional elemental distribution map with color; then splice the three-dimensional elemental distribution maps with color corresponding to multiple different angles to obtain the complete three-dimensional elemental distribution map with color 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 elements on the surface of an object in three-dimensional space, breaking through the limitation of two-dimensional images for the display of XRF scanning results, and avoiding the blur and distortion caused by the display of three-dimensional scanning results with two-dimensional images. Displaying the XRF scanning results in the form of a three-dimensional point cloud also makes it possible to perform a 360° annular scan of a three-dimensional object. Using the point cloud splicing technology guided by elemental distribution, the generation of a 360° annular elemental distribution map in space can be realized. In addition, using a three-dimensional point cloud to display the XRF scanning results allows users to conveniently rotate and zoom the scanning results to obtain the three-dimensional distribution of elements from various angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flowchart for generating a three-dimensional elemental distribution image of the present invention. Detailed implementation mode

[0025] The present invention will be further described in detail below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

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

[0027] 1) First, use a three-dimensional XRF scanning system to perform three-dimensional scanning on the target object, and collect spectral data and three-dimensional position information of each scanning point 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, element analysis is performed using the spectral data of each scanning point, and the relative content of each element distribution in each scanning point is calculated. Using the position information of each scanning point, an ordered three-dimensional point cloud conforming to the surface contour of the target object is generated.

[0029] 3) Since the spectral data and position information are given a unified retrieval method during the storage process, the element content information obtained from spectral analysis and the position information 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 color information is given to the element content. Different elements correspond to different colors, and the content of the same element corresponds to the brightness of the same color. After that, the color information of each scanning point is corresponded to the position information of the three-dimensional point cloud one by one, and a three-dimensional element distribution map with colors is generated in the form of a three-dimensional point cloud.

[0030] 4) Multiple scans from multiple angles generate multiple three-dimensional element distribution maps. Each three-dimensional 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 three-dimensional point cloud respectively. For a single color channel, based on the change of the color gradient, the area with high color change can be found as a feature point (the area with high color change in a single channel is the area where the pixel values of the image in this channel change relatively large, that is, the area where the pixel value gradient change is greater than the set ratio, and this ratio parameter is adjustable, not a fixed value). At the same time, for the distribution of different element types, the feature points of different color channels can be extracted and the three-dimensional coordinates of the feature points can be recorded. Then, the three-dimensional coordinates (x, y, z) of the three groups of feature points in the RGB three channels can be obtained. By using these element distribution characteristics combined with the contour characteristics of the three-dimensional point cloud, the feature matching of the point clouds at different angles can be realized more accurately, the overlapping part of the point clouds after recognition and matching can be removed, and thus multiple three-dimensional element distribution maps at different angles can be stitched into a complete three-dimensional element distribution map of the target object surface.

[0031] The method for feature matching in combination with the contour characteristics of the three-dimensional 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, so as to obtain the XYZ coordinates of three groups of feature points corresponding to the RGB three channels. Secondly, for the i-th angle, use a well-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] Input the four groups of feature points of the two three-dimensional element distribution maps into the feature matching function, which is a well-known feature matching method, to obtain the 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 adjacent angles such as the i + 1 or i - 1-th angle, that is, to determine which feature points among the feature points of the two angles are the same point in the base coordinate system. For example, if the feature points extracted for the i-th angle are points A and B, and the feature points for the i + 1 angle are points A and C, then through feature matching, it can be determined that point A is the repeated feature point in the two angles, and based on this, the three-dimensional element distribution map with color is subsequently spliced according to the matching result.

[0035] Although specific embodiments of the present invention are disclosed for illustrative purposes, the purpose is to help understand the content of the present invention and implement it accordingly. Those skilled in the art can understand that: without departing from the spirit and scope of the present invention and the appended claims, various substitutions, changes, and modifications are possible. Therefore, the present invention should not be limited to the content disclosed in the best embodiments, and the scope of protection required by the present invention is subject to the scope defined by 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) by changing the angle to generate a plurality of three-dimensional element distribution maps with colors corresponding to different angles; 5) stitching the colored three-dimensional element distribution maps corresponding to multiple different angles to obtain a complete colored three-dimensional element distribution map of the target object; wherein, the method for stitching the 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, extract a set of feature points based on the color gradient; use the feature points corresponding to each color channel at the i-th selected angle 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; then stitch the colored three-dimensional element distribution maps according to the feature matching results and remove overlapping point clouds.

2. The method according to claim 1, 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.

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

4. 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 a three-dimensional scan of 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, the color information corresponding to each point in the three-dimensional point cloud is determined according to the three-dimensional position information and color information of the scanning point, and a three-dimensional element distribution cloud with color is generated. Layout; then stitching the colored three-dimensional element distribution maps corresponding to multiple different angles to obtain a complete colored three-dimensional element distribution map of the target object; wherein the method for stitching the 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, extracting a set of feature points based on the color gradient; using the feature points corresponding to each color channel at the i-th selected angle combined with the contour features of the three-dimensional point cloud corresponding to the i-th selected angle, matching with the feature points extracted from the adjacent three-dimensional element distribution maps; then stitching the colored three-dimensional element distribution maps according to the feature matching results and removing the overlapping point clouds.

5. The system according to claim 4, 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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