Histograms files

[nasa92]

I managed to generate the files with your method. this generated me files for histograms. I traced them. for exemple

Please can you explain more about these histograms ? how do we interpret these histogram files ? What I understood the histograms represent the orientation of the gradient in each image pixel. but I cannot see this concepts with your histogram. and what is the difference between linear histogram file and other histogram file.

Thanks for you response

[valette]

I have added more info to the Readme, is it ok?

[nasa92]

yes that's better, thanks for that.
Is there a way to visualise keypoints in 3d slicer or an image ?