Studies On Some Issues Of Magnetic Resonance Image Processing

Magnetic resonance imaging technique has become one of the important tools in scientific research and clinic for its non-invasive, imaging with several parameters and reflecting biochemistry characterizations etc. This dissertation is focused on several important issues in magnetic resonance (MR) image processing. We did some studies on truncation artifact removal, MR image denoising and MR image fusion.Since the truncation artifact appear only in one of the two spatial directions, we decomposed the image with truncation artifact into approximate sub-images and vertical and horizontal detailed sub-images. We found that the truncation artifact caused by reducing the number of phase-coded signals were determined by some frequency components in vertical sub-images. In order to reduce the truncation artifact efficiently and preserve the details of the image as much as possible, we only manipulated operation to the vertical sub-images. The sub-images which had no relation with truncation artifact and the components with less truncation artifact are intact in image reconstruction. In this dissertation , we proposed three schemes for truncation artifact removal. We constructed smooth image with approximate sub-image and all parallel detailed sub-images. Then we reconstructed final image by adding details following a special rule. We only did artifact reduction to the vertical sub-images via wavelet shrinkage, then reconstructed the image with inverse dyadic wavelet transform. We decomposed the vertical sub-images further, retained the components which had less artifact...