Holographic bandwidth compression using spatial subsampling

Subject terms: electro-holography, holographic computation, holographic bandwidth compression, diffraction- specific, fringelet, hogel vector Abstract. A novel electro-holographic bandwidth compression technique, fringelet bandwidth compression, is described and implemented. This technique uses spatial subsampling to reduce the bandwidth and complex- ity of holographic fringe computation for real-time 3-D holographic displays. Fringelet bandwidth compres- sion is a type of diffraction-specific fringe computation, an approach that considers only the reconstruction process in holographic imaging. The fringe pattern is treated as a spectrum that is sampled in space (as holo- graphic elements or "hogels") and in spatial frequency (as "hogel vectors"). Fringelet bandwidth compression achieves a compression ratio of 16:1 without conspicuously degrading image quality. Further increase in com- pression ratio and speed is possible with additional image degradation. Fringelet decoding is extremely simple, involving the replication of fringelet sample values. This simplicity enables an overall increase in fringe com- putation speed of over 3000 times compared to conventional interference-based methods. The speed of fringe- let bandwidth compression has enabled the generation of images at nearly interactive rates: under 4.0 s per hand-sized (one-liter) 3-D image generated from a 36-Mbyte fringe.