Estimating scatter in X-ray images caused by imaging system components using kernels based on beam hardening

Patent metadata

Field	Value
Publication number	US-12433552-B2
Application number	US-202217970744-A
Country	US
Kind code	B2
Filing date	Oct 21, 2022
Priority date	Oct 21, 2022
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A computer-implemented method of reducing scatter in an X-ray projection image of an object, the method comprising: generating an initial X-ray projection image of an object with an imaging beam produced by an imaging system; based on a first transmission indicator for the object and on a second transmission indicator for at least one element of the imaging system, selecting a kernel for convolution of the initial projection image; convolving the initial X-ray projection image with the kernel to generate a scatter component of the initial X-ray projection image; and generating a corrected X-ray projection image by removing the scatter component from the initial X-ray projection image.

First claim

We claim:

1. A computer-implemented method of reducing scatter in an X-ray projection image of an object, the method comprising:
generating an initial X-ray projection image of an object with an imaging beam produced by an imaging system;
based on a first transmission indicator for the object and on a second transmission indicator for at least one element of the imaging system, selecting a kernel for convolution of the initial X-ray projection image, wherein the first transmission indicator is determined based on a portion of the object that is in a path of a ray that passes from an X-ray source of the imaging system to a first position in a detector array of an X-ray detector of the imaging system;
convolving the initial X-ray projection image with the kernel to generate a scatter component of the initial X-ray projection image; and
generating a corrected X-ray projection image by removing the scatter component from the initial X-ray projection image.

2. The computer-implemented method of claim 1 , wherein the first transmission indicator comprises a single value associated with a computed transmission of the imaging beam through the portion of the object.

3. The computer-implemented method of claim 1 , wherein the first transmission indicator includes a measure of a selective attenuation by the object of certain frequencies included in the imaging beam.

4. The computer-implemented method of claim 1 , wherein the first transmission indicator is based on attenuation of the imaging beam caused by the object being concentrated in a two-dimensional object that is located between the X-ray source of the imaging system and the detector array.

5. The computer-implemented method of claim 1 , wherein the at least one element of the imaging system comprises the X-ray detector, a bore of the imaging system, or a filter through which the imaging beam passes.

6. The computer-implemented method of claim 1 , wherein selecting the kernel for convolution of the initial X-ray projection image comprises:
selecting a first sub-kernel for convolution of a first portion of the initial X-ray projection image, wherein the first portion corresponds to a first position in the detector array; and
selecting a second sub-kernel for convolution of a second portion of the initial X-ray projection image, wherein the second portion corresponds to a second position in the detector array.

7. The computer-implemented method of claim 4 , wherein the second transmission indicator is based on the two-dimensional object being disposed at a plane of the imaging system.

8. The computer-implemented method of claim 7 , wherein the plane of the imaging system comprises an iso plane of the imaging system.

9. The computer-implemented method of claim 5 , wherein the filter comprises a bow-tie filter.

10. The computer-implemented method of claim 6 , wherein convolving the initial X-ray projection image with the kernel comprises convolving the first portion of the initial X-ray projection image with the first sub-kernel and convolving the second portion of the initial X-ray projection image with the second sub-kernel.

11. The computer-implemented method of claim 6 , wherein:
the detector array of the imaging system includes a plurality of positions; and
each position in the plurality of positions corresponds to a different portion of the initial X-ray projection image.

12. The computer-implemented method of claim 10 , wherein the first sub-kernel and the second sub-kernel are computed prior to generating the initial X-ray projection image.

13. The computer-implemented method of claim 11 , further comprising, for each position in the plurality of positions, selecting a different sub-kernel for convolution of a different corresponding portion of the initial X-ray projection image.

14. An X-ray imaging system, comprising:
an X-ray source for generating an imaging beam;
an X-ray detector; and
one or more processors configured to perform the steps of:
generating an initial X-ray projection image of an object with the X-ray detector and the imaging beam;
based on a first transmission indicator for the object and on a second transmission indicator for at least one element of the imaging system, selecting a kernel for convolution of the initial X-ray projection image, wherein the first transmission indicator is determined based on a portion of the object that is in a path of a ray that passes from the X-ray source to a first position in a detector array of the X-ray detector;
convolving the initial X-ray projection image with the kernel to generate a scatter component of the initial X-ray projection image; and
generating a corrected X-ray projection image by removing the scatter component from the initial X-ray projection image.

15. The X-ray imaging system of claim 14 , wherein the first transmission indicator comprises a single value associated with a computed transmission of the imaging beam through the portion of the object.

16. The X-ray imaging system of claim 14 , wherein the first transmission indicator includes a measure of a selective attenuation by the object of certain frequencies included in the imaging beam.

17. The X-ray imaging system of claim 14 , wherein the first transmission indicator is based on attenuation of the imaging beam caused by the object being concentrated in a two-dimensional object that is located between the X-ray source of the imaging system and the detector array.

18. A non-transitory computer readable medium storing instructions that, when executed by a processor, cause the processor to perform the steps of:
generating an initial X-ray projection image of an object with an imaging beam produced by an imaging system;
based on a first transmission indicator for the object and on a second transmission indicator for at least one element of the imaging system, selecting a kernel for convolution of the initial X-ray projection image, wherein the first transmission indicator is determined based on a portion of the object that is in a path of a ray that passes from an X-ray source of the imaging system to a first position in a detector array of an X-ray detector of the imaging system;
convolving the initial X-ray projection image with the kernel to generate a scatter component of the initial X-ray projection image; and
generating a corrected X-ray projection image by removing the scatter component from the initial X-ray projection image.

Assignees

• Siemens Healthineers Int Ag

Inventors

• Plamondon Mathieu
• Nagy Balazs
• Lehmann Mathias
• Strzelecki Adam Michal
• Peterlik Igor
• Seghers Dieter Marc

Classifications

• G06T12/10

  Image preprocessing, e.g. calibration, positioning of sources or scatter correction · CPC title

• A61B6/032 Primary

  Transmission computed tomography [CT] · CPC title

• G06T2207/10081

  Computed x-ray tomography [CT] · CPC title

• G06T2211/452

  involving suppression of scattered radiation or scatter correction · CPC title

• A61B6/5282

  due to scatter · CPC title