Reflectance and Shape from Images Using a Collinear Light Source

In this paper, a novel technique, called the photogeometric technique, is presented for surface reflectance extraction and surface recovery from an image sequence of a rotating object illuminated under a collinear light source (where the illuminant direction of the light source lies on or near the viewing direction of the camera). The rotation of the object is precisely controlled. The object surface is assumed to be smooth and uniform. The technique first computes the 3D locations of some surface points which give singular brightness values and builds the surface reflectance function by extracting the brightness values of these surface points from the image sequence. Then the technique uses the surface reflectance function and two images of the surface to recover surface depth and orientation simultaneously. The technique has been tested on real images of surfaces with different reflectance properties and geometric structures. The experimental results and comprehensive analysis show that the proposed technique is efficient and robust.