Q:

blending colors ios

I want to rectangular crop the eye from one face and paste it on another face, so that in the resulting image skin color of portion of eye blend nicely with the face color of the persons on which we are pasting eyes. I am able to crop and paste, but having problem with blending. Currently, the boundaries of the rectangular cropped eye after pasting are very much visible. I want to reduce this effect, so that the eyes nicely blend with face and resulting image won't look fake.

A:

My suggestion is to do the blending in code. First, you need do create two bitmap contexts so you have the bits of your face and the bits of your new eye.

in the overlap area only, you need to determine the outer most "skin" area by evaluating the colors of the two areas, and create a mapping of those areas in both that are "skin". you would be working from the outermost areas and work towards the center.
for color evaluation, you should turn colors into HSV (or HCL) and look at hue and saturation.
you will need to figure out some criteria for determining what is skin and what is eye
once you have defined the outer area - the one NOT an eye, but skin, you will blend. The blend will use more of the original based on its distance from the center of the eye (or distance to the ellipse defining the eye. Thus initially, the outer color will be say 5% new, 95% original.
as you get close to the eye, you will use more of the eye overlay skin color.

This should produce a really nice image. The biggest problem of course will be getting a good algorithm for separating eye from skin.

