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A high-resolution computer-generated stereogram for forming full-parallax three-dimensional (3-D) images is proposed. A full-parallax 3-D image is formed from 825 two-dimensional (2-D) projections and can be observed in a wide angular range. The stereogram is a reflective diffractive optical element (DOE) that consists of 50 x 50 μm² hogels, where each hogel corresponds to one pixel of the 2-D frames. A phase-type kinoform is computed in every hogel by solving a nonlinear inverse problem. The DOE relief is fabricated using electron-beam technology with pixel size of 0.2 x 0.2 μm². The effectiveness of the technology developed is illustrated by photographs and a video of a real DOE under monochromatic light and under white light. The new high-resolution full-parallax stereograms can be used for protecting bank notes, documents, and ID cards against counterfeit. [ABSTRACT FROM AUTHOR]

point light source (PLS) display with enhanced viewing angle (VA) is proposed. The maximum VA of a conventional PLS display is equal to the propagation angle of the PLS, so a light-source array (3 × 3) was used to enlarge the propagation angle of the PLS in the horizontal and vertical directions. The number of converging elemental image points increases due to the large propagation angle of the PLS; thus, the VA of the integrated point was enhanced. From the experimental results, the VA of the proposed method was 2.6 times larger than the maximum VA of a conventional PLS display [ABSTRACT FROM AUTHOR]

While color video endoscopy has enabled wide-field examination of the gastrointestinal tract, it often misses or incorrectly classifies lesions.Many of thesemissed lesions exhibit characteristic three-dimensional surface topographies. An endoscopic system that adds topographical measurements to conventional color imagery could therefore increase lesion detection and improve classification accuracy. We introduce photometric stereo endoscopy (PSE), a technique which allows high spatial frequency components of surface topography to be acquired simultaneously with conventional two-dimensional color imagery.We implement this technique in an endoscopic form factor and demonstrate that it can acquire the topography of small features with complex geometries and heterogeneous optical properties. PSE imaging of ex vivo human gastrointestinal tissue shows that surface topography measurements enable differentiation of abnormal shapes from surrounding normal tissue. Together, these results confirm that the topographical measurements can be obtained with relatively simple hardware in an endoscopic form factor, and suggest the potential of PSE to improve lesion detection and classification in gastrointestinal imaging. [ABSTRACT FROM AUTHOR]