发明授权
- 专利标题: Dynamic range compression/expansion of light beams by photorefractive crystals
- 专利标题(中): 通过光折变晶体动态范围压缩/扩展光束
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申请号: US125021申请日: 1987-11-24
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公开(公告)号: US4772785A公开(公告)日: 1988-09-20
- 发明人: Li-Jen Cheng , Hua-Kuang Liu
- 申请人: Li-Jen Cheng , Hua-Kuang Liu
- 申请人地址: DC Washington
- 专利权人: The United States of America as repesented by the Administrator, National Aeronautics and Space Administration
- 当前专利权人: The United States of America as repesented by the Administrator, National Aeronautics and Space Administration
- 当前专利权人地址: DC Washington
- 主分类号: G02F1/03
- IPC分类号: G02F1/03 ; H01J3/14
摘要:
Apparatus is provided which greatly reduces the intensity of bright portions of an image while only moderately reducing the brightness of dimmer portions of the image, to thereby compress the range of light intensities to facilitate detection of the image. The apparatus includes a light detector device formed by a chip of photorefractive material. A two-dimensional array of light beams from an object to be detected, passes through a beam splitter to form two arrays of light beams. The two arrays of light beams are directed at different angles against a surface of the chip of photorefractive material, the two arrays of light beams forming coincident images on the surface. One of the two-dimensional arrays of beams emerging from an opposite surface of the chip has a lower range of intensities, to facilitate detection of the object despite very bright spots on its image. The other array of light beams energing from the chip has a greater range of intensities than the unprocessed image of the object.