Correcting a ct scan image

Patent metadata

Field	Value
Publication number	US-2016110893-A1
Application number	US-201514918596-A
Country	US
Kind code	A1
Filing date	Oct 21, 2015
Priority date	Oct 21, 2014
Publication date	Apr 21, 2016
Grant date	—

Abstract

A method for correcting a CT scan image is provided. A target image including a target region to be corrected is extracted from an original CT scan image. A target projection range corresponding to the target region is obtained by orthographically projecting the target image, and target projection data within the target projection range is corrected. Noise of the corrected target projection data is adjusted to generate noise-adjusted target projection data to improve noise consistency between target region and the rest of the CT scan image. A corrected CT scan image is reconstructed based on the noise-adjusted target projection data.

First claim

1 . A method for correcting a CT scan image, the method comprising:
extracting a target image including a target region to be corrected from an original CT scan image; obtaining a target projection range corresponding to the target region by orthographically projecting the target image, and correcting target projection data within the target projection range; adjusting noise of the corrected target projection data to generate noise-adjusted target projection data to improve noise consistency between target region and the rest of the CT scan image; and reconstructing a corrected CT scan image based on the noise-adjusted target projection data.

2 . The method of claim 1 , wherein adjusting noise of the corrected target projection data to generate the noise-adjusted target projection data comprises:
converting the target projection data of an attenuation domain into target projection data of an intensity domain; multiplying the target projection data of the intensity domain by a default transform coefficient so as to obtain a transformed target projection data; using the transformed target projection data as a Poisson parameter to calculate a Poisson random number, and determining update transformed target projection data based on the Poisson random number; transforming the update transformed target projection data to update target projection data of the intensity domain; converting the update target projection data of the intensity domain into update target projection data of the attenuation domain; and determining the update target projection data of the attenuation domain as the noise-adjusted target projection data.

3 . The method of claim 1 , wherein adjusting noise of the corrected target projection data to generate the noise-adjusted target projection data comprises:
obtaining a noise value of a Gaussian distribution with zero mean; and summing the noise value with the target projection data so as to obtain the noise-adjusted target projection data.

4 . The method of claim 1 , wherein obtaining a target projection range corresponding to the target region by orthographically projecting the target image, and correcting target projection data within the target projection range comprises:
obtaining a linear interpolation value of two projection data points located at two adjacent sides of the target projection data; replacing the target projection data with the linear interpolation value so as to obtain corrected data of the target projection data; reconstructing a corresponding corrected image according to the corrected data of the target projection data; determining a reference image of the corrected image according to a default segmentation threshold; orthographically projecting the reference image so as to obtain reference projection data of the reference image; and determining the reference projection data as the corrected target projection data.

5 . The method of claim 1 , wherein reconstructing a corrected CT scan image based on the noise-adjusted target projection data comprises:
generating a first corrected CT scan image based on the noise-adjusted target projection data; and integrating the first corrected CT scan image with the target image so as to generate a second corrected CT scan image.

6 . The method of claim 1 , wherein the target region to be corrected is a metal region.

7 . A method for correcting a CT scan image, the method comprising:
extracting a target image including a target region to be corrected from an original CT scan image; obtaining a target projection range corresponding to the target region by orthographically projecting the target image, and correcting target projection data within the target projection range, wherein the target projection range comprises positions corresponding to all orthographical projection data of the target region; reconstructing a CT scan image based on the corrected target projection data; summing pixel values of the reconstructed CT scan image with a reference noise value so as to obtain pixel values of a corrected CT scan image; and generating the corrected CT scan image according to pixel values of the corrected CT scan image.

8 . The method of claim 7 , wherein the reference noise value is a noise value of a Gaussian distribution with zero mean.

9 . A device for correcting a CT scan image, the device comprising:
a processor configured to execute machine readable instructions corresponding to a control logic for correcting a CT scan image stored on a storage medium, wherein the machine readable instructions, when executed by the processor, cause the processor to: extract a target image including a target region to be corrected from an original CT scan image; obtain a target projection range corresponding to the target region by orthographically projecting the target image, and correct target projection data within the target projection range; adjust noise of the corrected target projection data to generate noise-adjusted target projection data to improve noise consistency between target region and the rest of the CT scan image; and reconstruct a corrected CT scan image based on the noise-adjusted target projection data.

10 . The device according to claim 9 , wherein said machine readable instructions further cause the processor to:
convert the target projection data of an attenuation domain into target projection data of an intensity domain; multiply the target projection data of the intensity domain by a default transform coefficient so as to obtain transformed target projection data; use the transformed target projection data as a Poisson parameter to calculate a Poisson random number, and determine update transformed target projection data based on the Poisson random number; transform the update converted target projection data to update target projection data of the intensity domain; convert the update target projection data of the intensity domain into update target projection data of the attenuation domain; and determine the update target projection data of the attenuation domain as the noise-adjusted target projection data.

11 . The device according to claim 9 , wherein said machine readable instructions further cause the processor to:
obtain a noise value of a Gaussian distribution with zero mean; and sum the noise value with the target projection data so as to obtain the noise-adjusted target projection data.

12 . The device according to claim 9 , wherein said machine readable instructions further cause the processor to:
obtain a linear interpolation value of two projection data points located at two adjacent sides of the target projection data; replace the target projection data with the linear interpolation value so as to obtain corrected data of the target projection data; reconstruct a corresponding corrected image according to the corrected data of the target projection data; determine a reference image of the corrected image according to a default segmentation threshold; orthographically project the reference image so as to obtain reference projection data of the reference image; and determine the reference projection data as the corrected target projection data.

13 . The device according to claim 9 , wherein said machine readable instructions further cause the processor to:
generate a first corrected CT scan image based on the noise-adjusted target projection data; and integrate the first corrected CT scan image with the target image so as to generate a second corrected CT scan image.

14 . The device according to claim 9 , wherein the target region to be corrected is a metal reg

Assignees

• Shenyang Neusoft Medical Sys

Inventors

• Pang Ling
• Han Junlong
• Lou Shanshan

Classifications

• G06T12/10

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

• A61B6/5205

  involving processing of raw data to produce diagnostic data · CPC title

• A61B6/5258 Primary

  involving detection or reduction of artifacts or noise · CPC title

• G06K9/46

  Physics · mapped topic

• G06T7/0081

  Physics · mapped topic