Stereoscopic system for 3D reconstruction using multispectral camera and LCD projector

The paper describes a stereoscopic system based on a multispectral camera and an LCD projector. The concept demonstrated consists in adding spectral information to threedimensional (3D) scene reconstruction. These data are provided by a multispectral camera equipped with interference filters. Before use, this system must be calibrated. This starts with a geometric calibration of the stereoscopic set using a weak calibration. Next, in order to recover the surface spectral reflectance curve of the scene, one must know the spectral response of the elements in the acquisition chain from the LCD projector to the camera. Then image acquisition can begin. In order to acquire a multispectral image, the LCD projector is used to project a luminous pattern onto the scene. The projected pattern is detected in the image and labelled. The 3D position of the different parts of the luminous pattern on the scene can be obtained using triangulation. Furthermore, a spectral reflectance curve is assigned to each part, allowing easy predictions of the scene under different illuminants. Thus, the use of a multispectral camera is justified by the fact that such a system presents an advantage over the classical RGB camera by providing more complete information.