Effects of contrast adjustment on visual gloss of natural textures

We propose a novel subband-based S-curve transformation for increasing the perceived contrast of images, and use it to explore the relation between perceived gloss and perceived contrast of natural textures. The proposed transformation makes minimal assumptions on lighting conditions and does not require prior knowledge of surface geometry. Through a series of subjective experiments with both complex real-world textures and synthesized Lambertian surfaces, we show that there is a strong and robust correlation between perceived contrast and perceived gloss, regardless of the composition of the texture. We also show that contrast modification of an image with near-frontal illumination can compensate for the change in perceived gloss due to an oblique illumination (of the same texture at the same viewing angle).