Fast generation of complex modulation video holograms using temporal redundancy compression and hybrid point-source/wave-field approaches

Abstract

International audienceThe hybrid point-source/wave-field method is a newly proposed approach for Computer-Generated Holo-gram (CGH) calculation, based on the slicing of the scene into several depth layers parallel to the hologram plane. The complex wave scattered by each depth layer is then computed using either a wave-field or a point-source approach according to a threshold criterion on the number of points within the layer. Finally, the complex waves scattered by all the depth layers are summed up in order to obtain the final CGH. Although outperforming both point-source and wave-field methods without producing any visible artifact, this approach has not yet been used for animated holograms, and the possible exploitation of temporal redundancies has not been studied. In this paper, we propose a fast computation of video holograms by taking into account those redundancies. Our algorithm consists of three steps. First, intensity and depth data of the current 3D video frame are extracted and compared with those of the previous frame in order to remove temporally redundant data. Then the CGH pattern for this compressed frame is generated using the hybrid point-source/wave-field approach. The resulting CGH pattern is finally transmitted to the video output and stored in the previous frame buffer. Experimental results reveal that our proposed method is able to produce video holograms at interactive rates without producing any visible artifact

Real-time embedded hologram calculation for augmented reality glasses

“…Over the last decades, several authors have proposed acceleration methods to reduce the hologram calculation time, including look-up tables [6][7][8] and wavefront recording planes [9,10] for the point-based approach, color-space conversion [11,12] and hybrid methods [13,14] for the layer-based approach, and analytic formulas [15][16][17] for the polygon-based approach. However, only a few works proposed compact embedded hardware implementations, required for AR applications.…”

Real-time computer-generated hologram calculation using pre-computed angular spectra

“…Commonly used primitives include points, 7 planar layers 8,9 and tilted polygons. 10 To reduce the hologram calculation time, several algorithms have been proposed, including using look-up tables, [11][12][13] wavefront recording planes 14,15 and redundancy removal techniques 16,17 for the point-source approach, color-space conversion, 18,19 fraction methods 20 and hybrid methods 21,22 for the layer-based approach, and using pre-computed light waves 23 or analytic formulas [24][25][26] for the polygon-based approach. Since they sample the scene using 3D primitives, the computational complexity of the aforementioned methods is always dependent on the number of primitives.…”