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The Fresnel-zone-aperture lensless camera using a fringe-scanning technique allows non-iterative well-conditioned image reconstruction; however, the spatial resolution is limited by the mathematical reconstruction model that ignores diffraction. To solve this resolution problem, we propose a novel image-reconstruction algorithm using the wave-optics-based design of the deconvolution filter and color-channel image synthesis. We verify a two-fold improvement of the effective angular resolution by conducting numerical simulations and optical experiments with a prototype.

In the calculation of large-scale computer-generated holograms, an approach called "tiling," which divides the hologram plane into small rectangles, is often employed due to limitations on computational memory. However, the total amount of computational complexity severely increases with the number of divisions. In this paper, we propose an efficient method for calculating tiled large-scale holograms using ray-wavefront conversion. In experiments, the effectiveness of the proposed method was verified by comparing its calculation cost with that using the previous method. Additionally, a hologram of 128K × 128K pixels was calculated and fabricated by a laser-lithography system, and a high-quality 105 mm × 105 mm 3D image including complicated reflection and translucency was optically reconstructed.

A holographic mirror is a reflection-type holographic optical element that works as an off-axis mirror. It realizes an upright see-through screen serving as a virtualimage display and virtual camera. Such screen enables to realize virtual-imagebased attractive applications like Pepper's ghost only with a thin optical system. This chapter describes the concept of a holographic-mirror-based virtual-image display and virtual camera, an experimental method for exposing the holographic mirror based on holographic printing, methods for dispersion compensation, and experimental results for the proposed virtual-image display and camera.

A computer-generated hologram based on ray-wavefront conversion can reconstruct photorealistic three-dimensional (3D) images containing deep virtual objects and complicated physical phenomena; however, the required computational cost has been a problem that needs to be solved. In this Letter, we introduce the concept of an orthographic projection in the ray-wavefront conversion technique for reducing the computational cost without degrading the image quality. In the proposed method, plane waves with angular spectra of the object are obtained via orthographic ray sampling and Fourier transformation, and only the plane waves incident on the hologram plane are numerically propagated. We verified this accelerated computational method theoretically and experimentally, and demonstrated optical reconstruction of a deep 3D image in which the effects of occlusions, transmission, refraction, and reflection were faithfully reproduced.