Photorealistic Style Transfer

Abstract:
Color grading is the process of subtly mixing and adjusting the color and tonal balance of a movie to achieve a specific visual look. This manual editing task may require a significant amount of work from very skilled artists and technicians. In many cases the director wants to emulate the style and look present in a reference image, e.g. a still from an existing movie, a photograph, or even a previously shot sequence in the current movie. In this paper we propose a method that automatically transfers the style, in terms of tone, color palette and contrast, from a reference image to the source RAW image. It consists of three separable operations: global luminance matching, global color transfer and local contrast matching. The computational complexity of the procedure is extremely low and allows for real-time implementation in-camera. As it just takes into account the statistics of source and reference images, no training is required. The results are free from artifacts and provide an excellent approximation to the intended look, bringing savings in pre-production, shooting and post-production time.

Photorealistic Style Transfer for Cinema Shoots