The numerical reconstruction for three-dimensional shape using digital holograms

in this paper, we introduce the potentialities of the digital hologram for the three-dimensional shape measurement from numerical reconstructed image. The image processing of the Fresnel digital hologram recorded by CCD sensor and the algorithm for 3d shape reconstruction is taken into account. Firstly, we stitch a series of small digital holograms to obtain a hologram with larger size. Secondly, the reconstructed image sequences of different depth planes are obtained by numerical reconstructing hologram. Finally, the depth information of each sample point of object is gained by algorithm of focus measure evaluation, in which the maximum focus measure of a region is found by the grey level variance of image sequence. The basic principle of this technique and its experimental verification are presented.