A method of illumination effect transfer between images using color transfer and gradient fusion

Illumination plays a crucial role to determine the quality of an image especially in photography. However, illumination alteration is quite difficult to achieve with existing image composition techniques. This paper proposes an unsupervised illumination-transfer approach for altering the illumination effects of an image by transferring illumination effects from another. Our approach consists of three phases. Phase-one layers the target image to three luminosity-variant layers by a series of pre-processing and alpha matting; meanwhile the source image is layered accordingly. Then the layers of the source image are recolored respectively by casting the colors from the corresponding layers of the target image. In phase-two, the recolored source image is edited to seamlessly transit at the boundaries between the layers using gradient fusion technique. Finally, phase-three recolors the fused source image again to produce a similar illuminating image with the target image. Our approach is tested on a number of different scenarios and the experimental results show that our method works well to transfer illumination effects between images.