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Adaptive Multi-contrast MR Image Denoising based on a Residual U-Net using Noise Level Map
Jiahao Hu1,2,3, Yilong Liu1,2, Zheyuan Yi1,2,3, Yujiao Zhao1,2, Fei Chen3, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China, 3Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
This study presents an adaptive multi-contrast MR image denoising based on a residual U-Net using a noise level map. The introduced noise level map can be manually set to fit different noise levels. The denoising results outperform BM3D in noise reduction and details preservation.
Fig. 1. (a) The architecture of the proposed multi-contrast denoising method using residual U-Net by combining U-Net and ResNet. (b) Residual blocks consisting of two convolutional layers with a ReLU activation in between. (c) Strided conv2D block consisting of a convolutional layer and ReLU activation. (d) Transposed conv2D block consisting of a transposed convolutional layer and ReLU activation.
Fig. 3. The denoising results for images with a higher noise level. The same level of noise (σ=25) was added to form noisy images. The proposed method remained similar performance, while BM3D smoothed the image details even more if attempt to reduce the noise to the same level as the proposed method.