Digital gamma correction circuit and digital gamma correction method

A digital gamma correction method configured such that a correction characteristic can be set, the method comprising:

• a correction characteristic storage step for storing, as data for defining the correction characteristic, data for specifying a basic broken line and data for specifying a curve approximation range extending below and above a break point on the basic broken line;
• a range determination step for determining whether input data lies within the curve approximation range based on the data stored by the correction characteristic storage step;
• an auxillary straight line coefficient calculation step for calculating a coefficient for an auxiliary straight line for defining the correction characteristic based on the input data as well as the data stored by the correction characteristic storage step;
• and
• a correction execution step for correcting the input data based on the basic broken line when the input data is determined by the range determination step to lie outside the range, while correcting the input data based on the auxiliary straight line when the input data is determined by the range determination step to lie within the range,
• wherein the auxiliary straight line coefficient calculation step is performed to obtain two division points at which two line segments of the basic broken line that are contained in the curve approximation range containing the input data are divided in proportion in which the curve approximation range is divided by the input data, and calculate a coefficient for an auxiliary straight line extending between the two division points.

A method for determining a gamma correction characteristic based on a basic broken line and a curve approximation range extending below and above a break point on the basic broken line, the method comprising:

• a range selection step for selecting the curve approximation range that contains input data;
• a proportion calculation step for calculating proportion in which the curve approximation range selected by the range selection step is divided by the input data;
• a division point calculation step for calculating two division points at which two line segments of the basic broken line that are contained in the curve approximation range selected by the range selection step are divided in the proportion calculated by the proportion calculation step;
• and
• a coefficient calculation step for calculating a coefficient for an auxiliary straight line extending between the two division points in order to determine gamma correction calculation that is to be applied to the input data.