is it possible to have orientation gradient based histogram for color images??

Answer 1

[Image Analyst]

The gradient is not a color thing. It has a magnitude and a direction. You may have those for each color plane (R, G, B) or you may have done the gradient on one of the HSV channels if you converted the image to SHV color space. You'd have to take the histogram of one of those images.

[tamanna]

ok i got it...can u tel me which histogram dscribe the best feature values

[Anand]

What do you mean by "best feature values"? What images are you working on and what features are you looking for?

[Image Analyst]

You said you wanted the histogram of gradients. That is used in SIFT and SURF. You can get SURF in the Computer Vision System Toolbox. If you want other features, then you have to define them. There could be thousand of them - we don't know what you're looking for. Maybe you need to do some research in CBIR (Content Based Image Retrieval).

[tamanna]

@ image analyst i read SIFT as wel a SURF. can u provide me original matlab coding for SIFT. what i got in your file exchange is modified version of SIFT

[tamanna]

@ anand actuly i am working on the ear images want to extract the features that are invariant to scale,rotation and occlusion. plz help me out if u can.

[Image Analyst]

Sorry, I don't have any code to share with anyone on SIFT or SURF.