finding similar colors programmatically

Question

I have a buffered image in java and I want to record how similar each pixel is to another based on the color value. so the pixels with 'similar' colors will have a higher similarity value. for example red and pink will have a similarity value 1000 but red and blue will have something like 300 or less.

how can I do this. when I get the RGB from a buffered Image pixel it returns a negative integer I am not sure how to implement this with that.

Answer 1

First, how are you getting the integer value?

Once you get the RGB values, you could try

((r2 - r1)² + (g2 - g1)² + (b2 - b1)²)^1/2

This would give you the distance in 3D space from the two points, each designated by (r1,g1,b1) and (r2,g2,b2).

Or there are more sophisticated ways using the HSV value of the color.

Answer 2

HSL is a bad move. L*a*b is a color space designed to represent how color is actually percieved, and is based on data from hundreds of experiments involving people with real eyes looking at different colors and saying "I can tell the difference between those two. But not those two".

Distance in L*a*b space represents actual percieved distance according to the predictions derived from those experiments.

Once you convert into L*a*b you just need to measure linear distance in a 3D space.