How to replace color of an image?

Question

I want to replace color of an image. For example turn all blue colors to red without any distortion on shape. When i try this i can swap the colors by iterating every pixel,

Answer 1

The problem with the issue that you are asking is that a strict color replacement will modify the shape of the image. What you need to do is get a little information on what the shape is. I.e. Find boundaries and shading along the boundaries. My suggestion to you is:

1. Use edge detection to separate out blobs
2. Find a blob that fits your demands: i.e. Has a tolerant likelihood for [color]ish.
3. Identify blobs and filters applied
4. Recolor the blob and reshade.

IMO: That is the only way you're going to get the result you're looking for.

Some notes: Finding a blob may require some testing to determine how much tolerance you have for blobs and shapes. [Connected Regions].

Another thing: The shading and relative coloring will require you to have a devience for the color you want.