I have a 480*640 depth image, and I got the normals (a 480*640*3 matrix) of each pixel from this depth image. Does anyone know how could I find the edge based on the normal information?
Thanks a lot!
An intuitive definition of an edge in a depth image is where the surface normal faces away from the viewer. Assuming a viewing direction [0 0 -1] (into the XY plane) any normal that has nearly vanishing z component can be characterized as an edge.
e = abs( depth(:,:,3) ) < 1e-3; %// a nice starting point
You need to set the threshold based on your data.
After that you might consider applying some non-maximal suppression or other morphological cleaning operations.