Adaptively Tuned Iterative Low Dose CT Image Denoising

Figure 7

Comparison of the effects of anisotropic diffusion, nonlocal mean, BM3D, and BM3D-NCRE. (a) In the original image, the circular regions show the area from which the noise variance is measured, the dashed rectangular region is the area which is shown in (d)-(e), and average noise of the three regions is around 55 HU. (b) Denoised by anisotropic diffusion, noise is around 25 HU. (c) Denoised by BM3D-NCRE, noise is around 25 HU. (d) Denoised by nonlocal mean, noise is around 21 HU. (e) Denoised by BM3D, noise is around 28 HU. ((f)–(j)) The zoomed-in region shown by dashed rectangle in image (a). The difference between original image and the image denoised by (k) anisotropic diffusion, (l) BM3D-NCRE, (m) nonlocal mean, and (n) BM3d are shown. The window width/window level in (a)–(j) is 1600/−300 HU and is 100/0 HU in (k)–(n).

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