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Arbitrary power function using logarithm lookup table

  • US 7,957,589 B2
  • Filed: 01/25/2007
  • Issued: 06/07/2011
  • Est. Priority Date: 01/25/2007
  • Status: Expired due to Fees
First Claim
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1. An image-processing device comprising:

  • a storage element storing data comprising a lookup table, the lookup table comprising a set of indices and logarithm data related to each index; and

    a processing circuit for performing a gamma translation process, wherein the processing circuit is configured to retrieve, from the lookup table, logarithm data based on a provided index and to retrieve an index, from the lookup table, based on a provided logarithm data,wherein the processing circuit is configured to;

    (a) determine the logarithm of a numerical color value by retrieving logarithm data from the lookup table using the color value as the index;

    (b) multiply the logarithm of the color value by a fractional portion of a gamma value, thus generating a first value; and

    (c) determine the inverse logarithm of the first value by searching the lookup table for logarithm data close to the first value and returning the index linking to the logarithm data as the inverse logarithm of the first value.

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