3-D shape measurement by self-referenced pattern projection method

Abstract A shape measurement system using time sequential space encoding with multi-gray scale patterns has been developed [1] , [2] , [3] . However, some objects that have colored surfaces and unevenness of reflectivity could not be measured using these methods. Therefore the reference projection images are added to the system. By the reference projection method, the colored objects could be measured by comparing observed space encoding images with the reference images. However the number of projections increased. In this paper, the self-referenced pattern projection method is proposed. This method reduces the number of projections and it is able to measure objects under an illuminated environment and to measure colored objects. Using this system, the measuring space is encoded into n ! sub-spaces with n projections. If there is a commercial projector to encode space with high pixel-resolution and brightness in the near future. it would greatly benefit this method to be able to divide the measuring space into the most sub-spaces when it has the least pattern projections.