Digital gamma correction method and apparatus

A digital gamma correction apparatus comprising:

• a gamma characteristic corrector which inputs image data values and outputs gamma-corrected image data values corresponding to said image data values, wherein said gamma characteristic corrector outputs said gamma-corrected image data values according to stored gamma correction information;
• storage means for storing differential data values, wherein each of said differential data values correspond to at least one of a plurality of gamma characteristics for gamma correcting said image data values and wherein said differential data values respectively correspond to differences between two values of said gamma-corrected image data values;
• characteristic selection means for outputting a gamma characteristic selection signal which represents a particular gamma characteristic of said plurality of gamma characteristics for gamma correcting said image data values;
• and
• control means for reading particular differential data values from said storage means, wherein said particular differential data values correspond to said particular gamma characteristic and wherein said control means generates said gamma correction information based on said particular differential data values and stores said gamma correction information in said gamma characteristic corrector, and wherein said gamma correction information comprises said input image data values and said gamma corrected image data values;
• wherein said control means comprises:
• a microprocessor which calculates said gamma-corrected image data values which respectively correspond to said image data values by accumulatively summing said particular differential data values which have been read from said storage means, and
• wherein said microprocessor causes said gamma characteristic corrector to store said gamma correction information which represents said gamma-corrected image data values and which represents a relationship between said image data values and said gamma-corrected image data values.

A digital gamma correction method for gamma-correcting digital input image data, the method comprising the steps of:

• (a) storing differential data values, wherein each of said differential data values correspond to at least one of a plurality of gamma characteristics for gamma correcting image data values to produce gamma-corrected image data values which correspond to said image data values and wherein said differential data values respectively correspond to differences between two values of said gamma-corrected image data values;
• (b) selecting a particular gamma characteristic from said plurality of gamma characteristics for gamma correcting image data values;
• (c) generating gamma correction information based on particular differential data values, wherein said particular differential data values are selected from said differential data values and correspond to said particular gamma characteristic and wherein said gamma correction information comprises said input image data values and said gamma-corrected image data values;
• (d) storing said gamma correction information;
• and
• (e) inputting said image data value and outputting said gamma-corrected image data values corresponding to said image data values based on said gamma correction information, wherein said step (a) comprises the step of:
• (a1) storing reference data values,
• wherein said reference data values respectively equal different values of said gamma-corrected image data values,
• wherein said different values of said gamma-corrected image data values are each determined by a different gamma characteristic of said plurality of gamma characteristics, and
• wherein said differences between two values of said gamma-corrected image data values are differences between two values of said gamma-corrected image data values which correspond to two adjacent values of said image data values.

A digital gamma correction method for gamma-correcting digital input image data, the method comprising the steps of:

• (a) storing differential data values, wherein each of said differential data values correspond to at least one of a plurality of gamma characteristics for gamma correcting image data values to produce gamma-corrected image data values which correspond to said image data values and wherein said differential data values respectively correspond to differences between two values of said gamma-corrected image data values;
• (b) selecting a particular gamma characteristic from said plurality of gamma characteristics for gamma correcting said image data values;
• (c) generating gamma correction information based on particular differential data values, wherein said particular differential data values are selected from said differential data values and correspond to said particular gamma characteristic and wherein said gamma correction information comprises said input image data values and said gamma-corrected image data values;
• (d) storing said gamma correction information;
• and
• (e) inputting said image data value and outputting said gamma-corrected image data values corresponding to said image data values based on said gamma correction information, wherein said step (c) comprises the step of:
• (c1) generating said gamma-corrected image data values which respectively correspond to said image data values by accumulatively summing said particular differential data values.

A digital gamma correction apparatus comprising:

• a gamma characteristic corrector which inputs image data values and outputs gamma-corrected image data values corresponding to said image data values, wherein said gamma characteristic corrector outputs said gamma-corrected image data values according to stored gamma correction information;
• storage means for storing differential data values wherein said differential data values respectively correspond to differences between two values of said gamma-corrected image data values and wherein said gamma-corrected image values are determined by a gamma characteristic for gamma correcting said image data values;
• and
• control means for reading said differential data values from said storage means for generating said gamma correction information based on said differential data values, and for storing said gamma correction information in said gamma characteristic corrector, wherein said gamma correction information comprises said input image data values and said gamma-corrected image data values,
• wherein said storage means stores a reference data value,
• wherein said reference data value equals a certain value of said gamma-corrected image data value determined by said gamma characteristic, and
• wherein said differences between two values of said gamma-corrected image data values are differences between two values of said gamma-corrected image data values which correspond to two adjacent values of said image data values.

A digital gamma correction apparatus comprising:

• a gamma characteristic corrector which inputs image data values and outputs gamma-corrected image data values corresponding to said image data values, wherein said gamma characteristic corrector outputs said gamma-corrected image data values according to stored gamma correction information;
• storage means for storing differential data values wherein said differential data values respectively correspond to differences between two values of said gamma-corrected image data values and wherein said gamma-corrected image values are determined by a gamma characteristic for gamma correcting said image data values;
• and
• control means for reading said differential data values from said storage means for generating said gamma correction information based on said differential data values, and for storing said gamma correction information in said gamma characteristic corrector, wherein said gamma correction information comprises said input image data values and said gamma-corrected image data values, wherein said control means comprises:
• a microprocessor which calculates said gamma-corrected image data values which respectively correspond to said image data values by accumulatively summing said differential data values read from said storage means, and
• wherein said microprocessor causes said gamma characteristic corrector to store said gamma correction information which represents said gamma-corrected image data values and which represents a relationship between said image data values and said gamma-corrected image data values.

An apparatus for gamma-correcting digital input image data, the apparatus comprising:

• storage means for storing first differential data values and second differential data values, wherein said first differential data values correspond to first gamma-corrected image data values and said second differential data values correspond to second gamma-corrected image data values, wherein said first and second gamma-corrected image data values respectively correspond to first and second gamma characteristics for gamma correcting said image data values, and wherein said first differential data values respectively correspond to differences between two values of said first gamma-corrected image data values and said second differential data values respectively correspond to differences between two values of said second gamma-corrected image data values;
• a gamma characteristic corrector which inputs said image data values and outputs one of said first and second gamma-corrected image data values, wherein said gamma characteristic corrector outputs said one of said first and second gamma-corrected image data values according to stored gamma correction information;
• characteristic selection means for outputting a gamma characteristic selection signal which corresponds to one of said first and second gamma characteristics;
• and
• control means for reading one of said first and second differential data values from said storage means based on said characteristic selection signal, for generating said gamma correction information based on said one of said first and second differential data values, and for storing said gamma correction information in said gamma characteristic corrector, wherein said gamma characteristic information comprises said image data values and said one of said first and second gamma-corrected image data values.