Computer-generated hologram of actual objects from arbitrary viewpoints with range sensors and digital cameras

Abstract

In computer-generated holograms (CGHs), various methods to generate holograms of actual objects have been proposed. One method uses the 3D information of actual objects obtained by one range sensor to generate a hologram. However, this method is unable to express occlusion because the 3D information is measured from only one viewpoint. Therefor, re-capturing 3D information is necessary to make CGHs from another viewpoint in this method. To overcome these problems, we have proposed a method that generates models of actual objects in a computer using two or more range sensors. In this method, CGHs are calculated by using multi-view images (MVIs) rendered from object models, which enables the occlusion to be expressed correctly. However, determination brightness values is unable to be performed on the whole object model because the luminance images are insufficient. This makes it difficult to generate CGHs from arbitrary viewpoints at one time. In this paper, we propose a method using additional digital cameras with range sensors to generate CGHs of actual objects from arbitrary viewpoints. This method determines the brightness values of the whole model using pictures taken by the additional cameras. The proposed method is advantageous in that re-capturing 3D information is unnecessary when CGHs are generated from another viewpoint. This method calculates CGHs with MVIs rendered from the model having brightness values. Results of computer simulations and optical reconstruction showed that it was possible to generate CGHs of actual objects with occlusion from arbitrary viewpoints.