Gradation correcting apparatus

A method of correcting a gradation comprising:

• creating frequency data for each luminance level of an input luminance signal every predetermined period;
• creating a corrected luminance level for each of a plurality of luminance levels based on said frequency data such that a luminance distribution of said input luminance signal extends over a predetermined dynamic range;
• calculating a statistical variance value for the luminance distribution in accordance with the frequency data to set a mixture ratio based on said statistical variance value;
• mixing other luminance levels and said corrected luminance levels corresponding thereto in said mixture ratio to obtain a mixed level;
• storing the mixed level as table data corresponding to each of said plurality of luminance levels;
• reading level data corresponding to each luminance level of said input luminance signal;
• and
• outputting said level data as a gradation corrected luminance signal.

An apparatus comprising:

• a memory in which frequency data for each luminance level of an input luminance signal for every predetermined period is stored, wherein a corrected luminance level for each of a plurality of luminance levels is created based on said frequency data, such that a luminance distribution of said input luminance signal extends over a predetermined dynamic range, wherein said corrected luminance levels for said plurality of luminance levels is stored in said memory;
• and
• a controller that calculates a statistical variance value for the luminance distribution in accordance with the frequency data in said memory to set a mixture ratio based on said statistical variance value, that mixes other luminance levels and corresponding ones of said corrected luminance levels in said memory based on said mixture ratio to obtain a mixed level, and that reads level data corresponding to each luminance level of said input luminance signal from said memory and outputs said level data as a gradation corrected luminance signal,
• wherein the mixed level generated by said controller is stored as table data corresponding to each of said plurality of luminance levels.