Harmonic colorization using proportion contrast

We present a proportion colour harmony model enhancing image aesthetics in terms of human colour perception. Given an arbitrary image, colours are modified to improve their proportion harmony. The proportion relationship between colours has been described in theories of colours but never proposed in computer graphics. Our model detects proportion harmony or the lack thereof harmony, proposes improvements verifying constraints defined by the user as well as different possibilities to recolor the image by shifting hues. Our technique is well-adapted to adjust the colour in an image, in a part of an image, image composition or a subset of colours depending on the user choices. Results show that our colour harmonization model allows the user to handle classical images such as photographs or drawings and paintings.