Comparison between nonlinear diffusion, total variation, and our optimized blockwise NL-means with wavelet mixing denoising on synthetic T1-w images. Top. Zooms on T1-w BrainWeb images. Left. The “ground truth”. Right. The noisy images with of Gaussian noise. Middle. The results of restoration obtained with the different methods and the images of the removed noise (i.e., the difference (centered on 128) between the noisy image and the denoised image. Bottom. The difference (centered on 128) between the denoised image and the ground truth. Left. Nonlinear diffusion denoising. Left. Nonlinear diffusion denoising. Middle. Total variation minimization process. Right. Optimized Blockwise NL-means
with WM filter. The NL-means-based restoration better preserves the anatomical structure in the image while efficiently removing the noise as it can be seen in the image of removed noise.
