Sharpen Function

Support
1

Hello dear Slicer Community,

I have the following question. On other DICOM imaging software (e.g. Planmeca Romexis or Ez3D) there is a “sharpness” slider or a “sharpen” filter with different degrees of sharpness (from “smooth” to “sharp”, s. Fig.1).

smooth
smooth2350×1256 112 KB

normal
normal2350×1256 136 KB

sharpen
sharpen2350×1256 179 KB

Fig.1-3: Slicer DICOM training data opened in Ez3D with “smooth” filter, no filter and “sharpen” filter

I have noticed that increasing the sharpness also increases the noise, which however for my purposes is not a problem.

I found that Slicer has a ‘LaplacianSharpeningImageFilter’ in the ‘Simple Filters’ module.
My question is if its effect should be the same as in the above examples (so far it seems so to me, s. Fig.2) and if there are other Slicer functions that correspond to the above mentioned “sharpen” function.

sno
sno768×498 145 KB

swith
swith768×500 139 KB

Fig.2: Similar slice as in Fig.1 opened in Slicer with no filter and ‘LaplacianSharpeningImageFilter’ applied

Regards

2

Yes, you are on the right track using SimpleFilters. There are dozens if not hundreds of filters and variants for denoising / sharpening that you can research in the ITK documentation. Many of these will improve the visual perception of sharpness, but from a quantitative imaging perspective they are altering the data or even throwing away the original signal data that may bias the results of something like segmentation or radiomics, so use them with caution.

3 Likes
3

You can try anisotropic diffusion filters, which can suppress noise while preserving more details.

1 Like
4

Thank you both very much, important information I will keep in mind.