Sir it is easy to segment images with clear background, but when i am trying for MRI images of Prostate or brain, then the segmentation is not upto the mark, i have tried changing certain parameters of your code, but failed to achieve perfection. please advise me how can i segment the MRI images using this technique..
It is a useful and fast program. I'm studying the coding of the version of region_seg.m modified on 14th Apr 2008 and hope to develop upon the code e.g. (incorporate termination criterion, use for other variation of snakes). Could you provide some insight regarding several questions listed here?
1. Problem anticipated: the program will have trouble when original image is double RGB. => all pixels become zero because of uint8(img).
Lines 140 to 143 seems not necessary.
2. Line 99, why change the level to 0.5 higher at interior of the contour, 0.5 lower at exterior of the contour?
3. Why +eps at line 51 when the values are the same without eps?
4. Line 124, for central difference of first derivative, is there a missing factor of 0.5 for the whole term? Won't this cause inconsistency in the spatial steps?
5. Line 134, why is there an additional factor (phi_x2 + phi_y2).^(1/2) for curvature (curvature formula I obtained is without this factor)?
6. How is line 60 obtained, which uses different time step each iteration?
7. Time step 0.5 for re-initialization (line 66) seems to be arbitrarily chosen. What is the bound this value can be varied within stable condition?
Thank you for your attention. Your insight is greatly appreciated!