Reflectance-aware optical flow

Hadi A. Dahlan, Edwin R. Hancock, William A. P. Smith

Abstract: In this paper, we present a reflectance-aware optical flow technique for nonrigidly aligning images captured in different lighting environments. We consider alignment between two specific lighting conditions of particular relevance to object capture using a light stage. The technique uses optical flow combined with three image transformation functions, namely a) the Illumination-Independent image transformation, b) the image colour transformation and c) the specular-invariant projection. We explore two types of photometric image alignment problem, i) aligning images captured with different spherical gradient patterns but the same types of light source and ii) aligning the spherical gradient sequence to an image captured with a different light source. Our results show that a previously proposed method can accurately solve the first problem and we propose a model-based approach to solving the second.