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.
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