| 摘要 |
PROBLEM TO BE SOLVED: To enable the effective utilization of the dynamic range of a video display device and to prevent the occurrence of black compression and white compression by executing contrast regulation according to the distribution of luminance levels, such as average luminance level and dispersion of the luminance levels. SOLUTION: The contrast regulation is executed according to the distribution of the luminance levels, such as the average luminance level and the dispersion of the luminance levels. The apparatus consists of a synchronizing signal separation circuit 1, a maximum value detection circuit 2, a minimum value detection circuit 3, a subtraction circuit 4, a divider circuit 5, a subtraction circuit 6, a multiplier circuit 7, a delay regulation circuit 8 and a synchronizing signal synthesis circuit 9. The delay regulation circuit 8 outputs the synchronizing signal D outputted from the synchronizing signal separation circuit 1 by delaying the signal for a specified time in order to synchronize the synchronizing signal D outputted from the synchronizing signal separation circuit 1 with the signal F outputted from the multiplier circuit 7. The synchronizing signal synthesis circuit 9 synthesizes the synchronizing signal outputted from the delay regulation circuit 8 and the output signal F of the multiplier circuit 7 and outputs the signal as a luminance signal G subjected to gradation correction.
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