3D shape measurements using stereo image scanner with three color light sources

In this paper, we propose a new measuring system using a "stereo image scanner" to measure a 3D colored object shape from its scanned image. This image scanner has two CCD image sensors and three color (red, green, and blue) light sources. We also propose the shape measuring method combining the binocular stereo and photometric stereo methods. An object shape can be primarily measured by photometric stereo method using three color light sources. Under these light sources, however, the object surface color varies with its shape, hence the object which has some color regions on its surface could not be measured by only a photometric stereo method. In order to measure a various colored object shape, first, we divide the scanned image into color regions using edge information. Next we measure the depth of edge points by a binocular stereo method using two CCD sensors, and estimate precise color (albedo) parameters at each region using depth data. Finally, by using albedo parameters we apply a photometric stereo method to measure the object shape precisely. In experiments, we demonstrate the measuring of a cylindrical object shape whose surface has many color regions, and show the effectiveness of our proposed method.