Removing noise using block DCT in Magnetic Resonance Images

Magnetic Resonance Imaging (MRI) is a medical imaging technique that has proven to be particularly valuable for examination of the soft tissues in the body. In this paper, a new denoising technique is proposed to remove the Rician noise from Magnetic Resonance Images using block DCT transform. It is well known that the noise in magnetic resonance imaging has a Rician distribution. Unlike additive Gaussian noise, Rician noise is signal dependent, and separating signal from noise is a difficult task. The proposed method adopt a weighted averaging schedule which uses direct component of small block DCTs to evaluate the weights. The proposed approaches were compared with other transform method such as wavelete thresholding methods, and produced much better results.