CN-121994838-A - Linear CT imaging system and scanning imaging method

CN121994838ACN 121994838 ACN121994838 ACN 121994838ACN-121994838-A

Abstract

The application provides a linear CT imaging system and a scanning imaging method, and relates to the technical field of radiation imaging and nondestructive detection. The system comprises a linear scanning channel and a scanning assembly, wherein the linear scanning channel is used for enabling a scanning object to pass through, the linear scanning channel extends along a first direction, the scanning assembly comprises a ray source and a detector, the ray source and the detector are arranged on opposite sides of the scanning channel along a second direction, the ray source is configured to emit ray beams, the detector comprises a plurality of detection units, the detection units are respectively configured to detect the ray beams emitted by the ray source and passing through the scanning object and generate projection data based on the detected ray beams, the scanning assembly and the scanning object move relatively in a linear mode, the data processing device is electrically connected with the detector, and the data processing device is configured to conduct superposition processing on at least two projection data generated by at least two detection units.

Inventors

ZHANG LI
SHEN LE
CHANG MING
HONG MINGZHI
YANG HONGKAI
HUANG QINGPING
LI LIANG
ZHAO ZHENHUA
Tian Zonghan

Assignees

同方威视技术股份有限公司
清华大学

Dates

Publication Date: 20260508
Application Date: 20260330

Claims (20)

1. A linear CT imaging system, the system comprising: A linear scan path for a scan object to pass through, the linear scan path extending along a first direction; A scanning assembly comprising a radiation source and a detector arranged on opposite sides of the scanning channel in a second direction, the radiation source being configured to emit a radiation beam, the detector comprising a plurality of detection units configured to detect the radiation beam emitted by the radiation source and passing through the scanning object, respectively, and to generate projection data based on the detected radiation beam, Wherein, the scanning component and the scanning object move relatively in a straight line; The system further comprises a data processing device electrically connected to the detector, the data processing device being configured to superimpose at least two projection data generated by at least two of the detection units.
2. The system of claim 1, wherein the detector comprises a plurality of rows of detection units arranged in a first direction, and the data processing device is configured to superimpose at least two projection data generated by at least two detection units located in different rows.
3. The system according to claim 1 or 2, wherein the data processing device is configured to superimpose at least two projection data generated by at least two detection units acquired at different times.
4. The system of claim 2, wherein the plurality of rows of detection units includes a first row of detection units and a second row of detection units, the first row of detection units being located on an upstream side of the second row of detection units in the direction of relative linear motion; The data processing device is configured to perform superposition processing on first projection data acquired at a first moment by at least one detection unit in a first row of detection units and second projection data acquired at a second moment by at least one detection unit in a second row of detection units, wherein the first moment is earlier than the second moment.
5. The system according to any one of claims 1 to 4, wherein the superimposition processing includes assigning respective weight coefficients to the at least two projection data to be superimposed, respectively, and performing weighted summation processing on the at least two projection data in accordance with the weight coefficients.
6. The system of claim 5, wherein the at least two projection data to be superimposed are each assigned the same weight coefficient, or wherein at least two of the at least two projection data to be superimposed are different, or wherein any two of the at least two projection data to be superimposed are each assigned different weight coefficients.
7. The system of any of claims 1-6, wherein the plurality of detection units are each configured to detect a beam of radiation emitted by the radiation source and passing through the scan object along a respective radiation path, and to generate projection data based on the detected beam of radiation; The data processing means are configured to superimpose at least two projection data generated by at least two of the detection units and having similar ray paths, The similar ray paths comprise a plurality of ray paths with the similarity of the ray paths meeting preset conditions.
8. The system of claim 7, wherein the ray path similarity is characterized by at least one of: Geometrical coincidence of multiple ray paths; The degree of difference in projection values of the plurality of projection data corresponding to the plurality of ray paths.
9. The system of claim 7 or 8, further comprising an imaging device configured to generate a three-dimensional reconstructed image based on target projection data generated by the plurality of target projection paths.
10. The system of claim 9, wherein each of the plurality of target projection paths corresponds to a plurality of similar ray paths; The data processing apparatus is configured to, for each target projection path, perform a superposition process on a plurality of projection data having a plurality of similar ray paths corresponding to the target projection path to generate target projection data corresponding to the target projection path.
11. The system of claim 10, wherein at least one of the target projection paths is one of a plurality of similar ray paths corresponding to the target projection path.
12. The system of claim 11, wherein at least one of the target projection paths is a ray path determined from a geometric relationship between a scanning assembly, a linear scanning channel, and a scanned object in the system.
13. The system according to any one of claims 7-12, wherein the data processing apparatus is configured to characterize the alike ray path with a three-dimensional vector corresponding to a straight-line path from the ray source to the detection unit in response to the absence of a priori information of the scanned object.
14. The system of any of claims 7-12, wherein the data processing apparatus is configured to characterize the similar ray paths with three-dimensional vectors corresponding to straight-line paths from a location where a ray beam enters the scan object to a location where the ray beam leaves the scan object in response to the presence of a priori information of the scan object.
15. The system of any one of claims 7-14, wherein the relative linear motion of the scan object is v, the sampling frequency of the detector is f, the minimum spacing between two adjacent target projection paths on the central axis of the linear scan channel is d, and the velocity v, the frequency f, and the spacing d satisfy the following relationship v/f < d.
16. The system of any one of claims 7-15, wherein the ray path similarity is characterized by the following function: g(p 1 ,p 2 )=w 1 cosθ+w 2 e -as , Wherein p 1 、p 2 represents two ray paths respectively, g (p 1 ,p 2 ) represents the similarity of the two ray paths p 1 、p 2 , θ represents the included angle of the two ray paths p 1 、p 2 , s represents the interval distance of the two ray paths p 1 、p 2 on the central axis of the linear scanning channel, the parameter a is used for controlling the sensitivity of the interval distance, and w 1 and w 2 are weight coefficients.
17. The system of any one of claims 7-15, wherein the ray path similarity is characterized by the following function: g(p 1 ,p 2 )=(w 1 cosθ+w 2 e -as )*(1/(|prj(p 1 )–prj(p 2 )|+b)), Wherein p 1 、p 2 represents two ray paths respectively, g (p 1 ,p 2 ) represents the similarity of the two ray paths p 1 、p 2 , θ represents the included angle of the two ray paths p 1 、p 2 , s represents the interval distance between the two ray paths p 1 、p 2 on the central axis of the linear scanning channel, the parameter a is used for controlling the sensitivity of the interval distance, w 1 and w 2 are weight coefficients, prj (p 1 ) represents the projection value of the projection data corresponding to the ray path p 1 , prj (p 2 ) represents the projection value of the projection data corresponding to the ray path p 2 , and the parameter b is a weight factor, b >0.
18. The system of any of claims 7-17, wherein the ray path similarity satisfying a preset condition comprises at least one of: the similarity calculated through the function is larger than a preset threshold value; The class similarity calculated by the function is ranked in the first N bits, wherein N is the number of preset similar ray paths.
19. The system of any of claims 7-18, wherein the superposition process comprises: Calculating the similarity of a plurality of ray paths and a target ray path p m respectively according to the function aiming at the target ray path p m ; Selecting N similar ray paths with the similarity row of the N bits at the front position calculated by the function, wherein the similarity between a j-th ray path p j in the N similar ray paths and the target ray path p m is g (p m ,p j ), and j is more than or equal to 1 and less than or equal to N; Acquiring N projection values corresponding to the N similar ray paths, wherein the projection value corresponding to a j-th ray path p j in the N similar ray paths is prj (p j ); Each of the N projection values is given a weight coefficient, wherein the weight coefficient corresponding to the projection value prj (p j ) is q (p j ); the N projection values are weighted and summed to obtain a target projection value prj (p m ) corresponding to the target ray path p m using the following equation: 。
20. The system of claim 19, wherein the weight coefficient q (pj) is calculated by the following equation: 。

Description

Linear CT imaging system and scanning imaging method Technical Field The application relates to the technical field of radiation imaging and nondestructive testing, in particular to a linear CT imaging system and a scanning imaging method. Background Linear CT is an imaging modality that differs from conventional CT rotational scanning in that the source and detector are in linear motion relative to the object being scanned, rather than rotational motion of conventional CT. The scanning mode avoids mechanical rotating parts, has a relatively simple structure, can realize flexible and rapid scanning, and has application potential in the fields of industrial nondestructive detection (such as online detection), safety inspection and the like. How to improve the image quality of linear CT scanning imaging has been one of the important subjects of interest to the researchers in the relevant fields. It should be noted that the above information disclosed in this section is only for understanding the background of the inventive concept and thus, the above information may include information that does not constitute prior art. Disclosure of Invention In view of at least one of the above-mentioned technical problems, an embodiment of the present application provides a linear CT imaging system, comprising a linear scanning channel for a scanning object to pass through, the linear scanning channel extending in a first direction, a scanning assembly comprising a radiation source and a detector arranged on opposite sides of the scanning channel in a second direction, the radiation source being configured to emit a radiation beam, the detector comprising a plurality of detection units each configured to detect the radiation beam emitted by the radiation source and passing through the scanning object and to generate projection data based on the detected radiation beam, wherein the scanning assembly and the scanning object are in a relative linear motion, the system further comprising a data processing device electrically connected to the detector, the data processing device being configured to superimpose at least two projection data generated by the at least two detection units. According to some embodiments of the application the detector comprises a plurality of rows of detection units arranged in a first direction, the data processing means being configured to superimpose at least two projection data generated by at least two detection units located in different rows. According to some embodiments of the application the data processing device is configured to superimpose at least two projection data generated by at least two detection units acquired at different times. According to some embodiments of the application, the plurality of rows of detection units comprises a first row of detection units and a second row of detection units, the first row of detection units being located on an upstream side of the second row of detection units in a direction of relative linear movement, and the data processing device is configured to superimpose first projection data acquired by at least one detection unit located in the first row of detection units at a first time and second projection data acquired by at least one detection unit located in the second row of detection units at a second time, wherein the first time is earlier than the second time. According to some embodiments of the application, the superposition processing includes assigning respective weight coefficients to at least two projection data to be superimposed, respectively, and performing weighted summation processing on the at least two projection data according to the weight coefficients. According to some embodiments of the present application, the at least two projection data to be superimposed are each assigned the same weight coefficient, or at least two of the at least two projection data to be superimposed are different, or any two of the at least two projection data to be superimposed are each assigned different weight coefficients. According to some embodiments of the application, the plurality of detection units are respectively configured to detect a ray beam emitted by the ray source and passing through the scanned object along respective ray paths and generate projection data based on the detected ray beams, and the data processing device is configured to perform superposition processing on at least two projection data generated by at least two detection units and having similar ray paths, wherein the similar ray paths comprise a plurality of ray paths of which the similarity of the ray paths satisfies a preset condition. According to some embodiments of the application, the similarity of ray paths is characterized by at least one of a geometrical overlap ratio of the plurality of ray paths and a difference ratio of projection values of the plurality of projection data corresponding to the plurality of ray paths. According to some embodiments of