A holographic stereograms generation technique based on multi-view displays does not require diffraction calculation when generating holographic stereograms from multiple perspective projections of real objects. However, a viewing area was limited when the spatial frequency of the quadratic phase distribution exceeds the Nyquist frequency determined by the pixel pitch of the spatial light modulator. In this study, we improved the technique by introducing a spherical lens on the hologram display plane to provide a quadratic phase distribution to wavefronts. Because of random phase distributions that were added to the parallax images to obtain smooth motion parallax, speckle noise was observed in reconstructed images. To reduce the speckle noise, the spatial bandwidths of the wavefronts were limited. The proposed technique was verified experimentally.
A fast technique to calculate computer-generated holographic stereograms is proposed. We assume that the three-dimensional image generation by holographic stereograms might be similar to that by multi-view autostereoscopic displays; multiple parallax images are displayed with rays converging to corresponding viewpoints. Therefore, a wavefront whose amplitude is the square root of an intensity distribution of the parallax image and phase is a quadric phase distribution of a spherical wave converging to the viewpoint is considered. Multiple wavefronts are calculated for multiple viewpoints and are summed up to obtain an object wave. The proposed technique was verified experimentally.