I am intersted with determining branchpoints of retinal images and then registering these images. First of all I am using a algorithm for extracting of vessels from image then skeletization and finding branchpoints. At first operation all things were ok but if I rotate same image by randomize angle, number of branchpoints are very increase. what are your opinions about this problem...

related links of images : http://e1204.hizliresim.com/w/6/449m6.jpg http://e1204.hizliresim.com/w/6/449by.jpg

• matlab

imrotate's standard interpolation algorithm is nearest neighbor, that tends to transform your image in a beautiful saw.

If you rotate your image with imrotate, try passing as the third parameter a better method, like bicubic or bilinear, both will be much better.

The syntax is simple:

imrotate(img, degrees, 'bicubic');