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1.发明授权公开(公告)号：US10825210B2
公开(公告)日：2020-11-03
申请号：US16206892
申请日：2018-11-30
Applicant: CANON MEDICAL SYSTEMS CORPORATION , THE UNIVERSITY OF CENTRAL FLORIDA RESEARCH FOUNDATION, Inc.
Inventor： Qiulin Tang , Alexander Katsevich , Zhou Yu , Wenli Wang
Abstract: An apparatus and method are provided for computed tomography (CT) imaging to reduce truncation artifacts due to a part of an imaged object being outside the scanner field of view (FOV) for at least some views of a CT scan. After initial determining extrapolation widths to extend the projection data to fill a truncation region, the extrapolation widths are combined into a padding map and smoothed to improve uniformity and remove jagged edges. Then a hybrid material model fits the measured projection data nearest the truncation region to extrapolate projection data filling the truncation region. Smoothing the padding map is improved by the insight that in general smaller extrapolation widths are more accurate and trustworthy. Further, practical applications often include multiple inhomogeneous materials. Thus, the hybrid material model provides a better approximation than single material models, and more accurate fitting is achieved.
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2.发明申请公开(公告)号：US20190164317A1
公开(公告)日：2019-05-30
申请号：US16206892
申请日：2018-11-30
Applicant: CANON MEDICAL SYSTEMS CORPORATION , THE UNIVERSITY OF CENTRAL FLORIDA RESEARCH FOUNDATION, Inc.
Inventor： Qiulin Tang , Alexander Katsevich , Zhou Yu , Wenli Wang
Abstract: An apparatus and method are provided for computed tomography (CT) imaging to reduce truncation artifacts due to a part of an imaged object being outside the scanner field of view (FOV) for at least some views of a CT scan. After initial determining extrapolation widths to extend the projection data to fill a truncation region, the extrapolation widths are combined into a padding map and smoothed to improve uniformity and remove jagged edges. Then a hybrid material model fits the measured projection data nearest the truncation region to extrapolate projection data filling the truncation region. Smoothing the padding map is improved by the insight that in general smaller extrapolation widths are more accurate and trustworthy. Further, practical applications often include multiple inhomogeneous materials. Thus, the hybrid material model provides a better approximation than single material models, and more accurate fitting is achieved.
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公开(公告)号：US10755395B2
公开(公告)日：2020-08-25
申请号：US14953221
申请日：2015-11-27
Applicant: CANON MEDICAL SYSTEMS CORPORATION
Inventor： Zhou Yu , Qiulin Tang , Satoru Nakanishi , Wenli Wang
Abstract: An apparatus and method of denoising a dynamic image is provided. The dynamic image can represent a time-series of snapshot images. The dynamic image is transformed, using a sparsifying transformation, into an aggregate image and a series of transform-domain images. The transform-domain images represent kinetic information of the dynamic images (i.e., differences between the snapshots), and the aggregate image represents static information (i.e., features and structure common among the snapshots). The transform-domain images, which can be approximated using a sparse approximation method, are denoised. The denoised transform-domain images are recombined with the aggregate image using an inverse sparsifying transformation to generate a denoised dynamic image. The transform-domain images can be denoised using at least one of a principal component analysis method and a K-SVD method.
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