A Mobile True Color Topometric Sensor for Medical and Art Conservation Applications

For many applications of 3-D measurement techniques the color of the surface under investigation is of similar importance as the geometry. This is especially the case in the field of art conservation and for medical tasks. A 3-D coordinate measurement system based on the fringe projection technique is presented that uses high-resolution color CCD cameras with digital interfaces which allow a simplified photogrammetric calibration as well as a true color reproduction. Combined with a standard digital video beamer for fringe projection and controlled by a notebook a very compact, mobile and all-purpose 3-D sensor is implemented. The measuring system allows to record up to 0.8 million 3-D coordinates with color information in less than three seconds. The applied colorimetric techniques to improve color reproduction are discussed and results of measurements of cultural assets and facial structures are presented.