A Post-processing Method for Removing Ring Artifacts in CT Images

A technology for ring artifacts and CT images, which is applied in the field of medical image processing, can solve the problems of ring artifacts with poor ring removal effect and image resolution reduction.

Active Publication Date: 2011-12-14
NEUSOFT MEDICAL SYST CO LTD
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  • Abstract
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Problems solved by technology

[0016] Aiming at the inadequacy of the ring artifact in the CT image in the prior art, the technical problem to be solved is to provide a method that does not reduce the resolution

Method used

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  • A Post-processing Method for Removing Ring Artifacts in CT Images
  • A Post-processing Method for Removing Ring Artifacts in CT Images
  • A Post-processing Method for Removing Ring Artifacts in CT Images

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Embodiment Construction

[0079] The present invention removes the post-processing of ring artifacts in CT images in an image with ring artifacts (such as figure 1 As shown), in order to facilitate the analysis, the image f(x, y) in the original Cartesian coordinate system with rings is now decomposed into a Cartesian coordinate image g(x, y) without a ring and a Cartesian coordinate image with a ring The sum of h(x, y), ie

[0080] f(x,y)=g(x,y)+h(x,y) (1)

[0081] The purpose of deringing is to obtain g(x, y). According to formula (1), an acyclic coordinate image g(x, y) can be obtained; or directly obtain g(x, y); or first obtain a ringed The Cartesian coordinate image h(x, y), and then subtract the Cartesian coordinate image h(x, y) with ring from the image f(x, y) in the original Cartesian coordinate system with ring, and then get the rectangular coordinate without ring coordinate image g(x, y). In order to maintain the resolution of the image and make the resolution consistent before and after...

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Abstract

The invention relates to a post-processing method for removing ring artifacts in a CT (computed tomography) image, and the post-processing method comprises the following steps: converting the CT image with ring artifacts from a rectangular coordinate image to a polar coordinate image; extracting the ring image in polar coordinates with a comb filter in a polar coordinate image domain; converting the ring image extracted out of the polar coordinates to a ring image in rectangular coordinates; and subtracting the ring image in the rectangular coordinates from the original CT image with the ringartifacts to obtain a ring-free image. Through frequency domain comb filtering technology, the post-processing method provided by the invention subtracts the corresponding ring artifact image from the original image, without reduction of image resolution and change of quality of the original image. The post-processing method achieves the processing effect, and meanwhile the speed meets product requirements and has space for further optimization, so that the post-processing method is fully suitable for a CT machine with higher requirements for the reconstruction speed.

Description

technical field [0001] The invention relates to medical image processing technology, in particular to a post-processing method for removing ring artifacts in CT images. Background technique [0002] The ring artifacts that appear in CT images are caused by the inconsistent response of single or multiple channels in the detector in the CT machine. Since each channel unit of the detector cannot physically respond exactly the same, the ring artifacts Shadows are unavoidable, but the intensity and brightness of the artifacts are different. [0003] figure 1 is an image with ring artifacts, by figure 1 It can be seen that the shape of the ring artifact is several circles around the center of rotation, and its intensity can be light or heavy, and the brightness can be bright or dark, depending on the position of the channel where the error occurs and the size of the error. The ring artifact seriously affects the image quality, so it is very necessary to remove the ring artifact...

Claims

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Application Information

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IPC IPC(8): A61B6/03
Inventor 孙洪雨
Owner NEUSOFT MEDICAL SYST CO LTD
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