3D-shape reconstruction based on a sub-pixel-level mapping relationship between the camera and projector

To some extent, the mapping relationship between the camera and projector images determines the precision of surface reconstruction in digital close-range photogrammetry. In this paper, a new method is presented to achieve sub-pixel-level mapping between the camera and projector images. Instead of mapping the stripe from the camera to the projector, which is pixel-precision-based, a set of pixels that share the same decoded number were picked out on the camera images and their barycenter was calculated to mapped onto the pixel on the projector images. In most cases, the calculation of the barycenter is able to achieve sub-pixel precision. Compared with existing approaches based on the direct mapping of the stripe on the camera image to the projector image, the proposed method is characterized by higher accuracy in mapping the points and thus the surface reconstruction performance. The experimental results are presented to show the effectiveness of the proposed method in the improvement of the accuracy of shape reconstruction.