Image Reconstruction by Computer in Acoustical Holography

Abstract

In acoustical holography the reconstruction techniques of images from recorded acoustical holograms are classified mainly into three categories, that is, 1) optical reconstruction,¹ 2) numerical reconstruction,^2–4 3) reconstruction by non-optical waves.⁵ In these reconstruction techniques, the optical reconstruction is mostly investigated for its excellent capability for processing large amount of twodimensional holographic information and its easiness in reproducing images with visible light. However the optical reconstruction has its inconvenience, that is it needs a photographic process when the acoustical holograms are recorded on films, making it impossible to reconstruct images in real time. The image reconstruction by non-optical waves, for example acoustical waves,⁵ now is used for special purpose and few investigations are conducted on this technique.