发明公开
EP0578950A3 Method and apparatus for converting floating-point pixel values to byte pixel values by table lookup
失效
用于转换浮点像素值的方法和装置通过表查找来计算像素值
- 专利标题: Method and apparatus for converting floating-point pixel values to byte pixel values by table lookup
- 专利标题(中): 用于转换浮点像素值的方法和装置通过表查找来计算像素值
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申请号: EP93108197.0申请日: 1993-05-19
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公开(公告)号: EP0578950A3公开(公告)日: 1995-11-22
- 发明人: Lucas, Bruce David
- 申请人: International Business Machines Corporation
- 申请人地址: Old Orchard Road Armonk, N.Y. 10504 US
- 专利权人: International Business Machines Corporation
- 当前专利权人: International Business Machines Corporation
- 当前专利权人地址: Old Orchard Road Armonk, N.Y. 10504 US
- 代理机构: Schäfer, Wolfgang, Dipl.-Ing.
- 优先权: US914978 19920715
- 主分类号: H03M7/24
- IPC分类号: H03M7/24 ; G06F1/03 ; G06F15/62
摘要:
The invention provides a method of generating a value of a pixel, and apparatus for accomplishing the method. The method includes the steps of (a) providing a floating-point representation of a pixel value; and (b) applying the floating-point representation as an index into a lookup table, the lookup table including a memory device having a plurality of entries. Each of the entries is uniquely indexed by one value of a floating-point representation of a pixel value, and each of the entries stores a corresponding integer representation of the pixel value. A third step (c) outputs from the lookup table the integer representation of the pixel value that corresponds to the applied floating-point representation. It is shown that only a sub-set of the entire floating-point representation need be employed as a table index value. In the presently preferred embodiment of the invention, only 16 bits of a 32-bit single-precision floating-point value are shown to be relevant to the result; specifically the sign bit, the exponent, and a portion of the mantissa.
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