What is the difference between Gray map of image and edge map of image?

i want to know the difference between Gray map of image and edge map of image and how to subtract them from each other

Answer 1

[Image Analyst]

I've never heard of a gray map of an image. Maybe you mean a gray scale colormap applied to an indexed image, or maybe you just mean a plain old regular grayscale image. An edge map is an image that indicated where edges are in the image. The image would have undergone some kind of edge detection filter and the values in the edge map image may reflect the strength of the edge, or it may have already been thresholded (like the edge() function) so that you have a binary image. I have no idea why you would subtract an edge map from anything, unless perhaps you wanted to suppress or soften only the edges in an image by subtracting the edge image from the original image. This is hardly ever done though. Usually people want to emphasize edges, not soften them.

[Isee You]

[Isee You]

that what i want to do? i got the gray liver image and i do some process on it then i want to subtract gray map(i don't know hot to get it )and edge map image to find difference areas if you want you can see this pdf http://www.mediafire.com/file/jgjciml9949o7fm/liver_tumor_detection.pdf

[Image Analyst]

I have no idea. They're using terminology that doesn't seem very standard or intuitive. Their gray map isn't gray and their edge map does not look like it would be something that would indicate where edges are. They may have custom definitions for these things in their paper.

[As Bdg]

Hello, Do you have the code of detection of the edge map of the image please ?