Open AccessSparse representation based computed tomography images reconstruction by coupled dictionary learning algorithm
Author(s) -
Deeba Farah,
Kun She,
Ali Dharejo Fayaz,
Zhou Yuanchun
Publication year - 2020
Publication title -
iet image processing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 45
eISSN - 1751-9667
pISSN - 1751-9659
DOI - 10.1049/iet-ipr.2019.1312
Subject(s) - sparse approximation , artificial intelligence , k svd , computer science , pattern recognition (psychology) , similarity (geometry) , dictionary learning , image (mathematics) , data set , peak signal to noise ratio , resolution (logic) , iterative reconstruction , noise (video) , set (abstract data type) , image resolution , medical imaging , algorithm , computer vision , programming language
It is very interesting to reconstruct high‐resolution computed tomography (CT) medical images that are very useful for clinicians to analyse the diseases. This study proposes an improved super‐resolution method for CT medical images in the sparse representation domain with dictionary learning. The sparse coupled K‐singular value decomposition (KSVD) algorithm is employed for dictionary learning purposes. Images are divided into two sets of low resolution (LR) and high resolution (HR), to improve the quality of low‐resolution images, the authors prepare dictionaries over LR and HR image patches using the KSVD algorithm. The main idea behind the proposed method is that sparse coupled dictionaries learn about each patch and establish the relationship between sparse coefficients of LR and HR image patches to recover the HR image patch for LR image. The proposed method is compared to conventional algorithms in terms of mean peak signal‐to‐noise ratio and structural similarity index measurements by using three different data set images, including CT chest, CT dental and CT brain images. The authors also analysed the proposed improved method for different dictionary sizes and patch size to obtain a similar high‐resolution image. These parameters play an essential role in the reconstruction of the HR images.