Patent ID: 8456482

Claim:
A gamma curve adjustment device being used to adjust a gamma curve, wherein the gamma curve indicates a relationship of input tone values to output tone values and the gamma curve is used in a gamma correction circuit that performs gamma correction an image signal, the gamma curve adjustment device comprising: a user interface module configured to enable a user to specify desired output tone values for a plurality of pre-established adjustment points on the gamma curve; and an adjustment module configured to adjust the gamma curve such that the output tone value at each adjustment point matches the value specified through the user interface module, wherein the plurality of adjustment points are established such that the adjustment points at a center of the gamma curve are more closely spaced in the input direction than the adjustment points at the ends of the gamma curve; the center cart of the gamma curve is a part of the gamma curve in a tone range from the lower 20% to 60% of the entire input tone value range; the user interface module is configured to increase or decrease the output tone values in units of minimum increment/decrement steps which are pre-established for adjustment points, thereby enabling the user to specify the output tone value at each adjustment point; the minimum increment/decrement steps are established such that, for a least some adjustment points among the plurality of adjustment points, the minimum increment/decrement step established for these adjustment points differs from the minimum increment/decrement step established for other adjustment points; and the minimum increment/decrement steps for adjustment points are established such that the minimum increment/decrement step established for the adjustment points present in the low tone range of the input tone values is greater than the minimum increment/decrement step established for the adjustment points present in the high tone range of the input tone values.