Patent ID: 7884857

Claim:
An image pickup apparatus comprising: a histogram detecting unit that detects a distribution of numbers of pixels by luminance level of a picked-up image signal; a maximum luminance value calculating unit that calculates a maximum luminance value of the picked-up image signal; a high luminance proportion calculating unit that calculates a proportion of a high luminance signal out of all of the pixels composing one or a plurality of frames based on the distribution of numbers of pixels by luminance level detected by the histogram detecting unit; a knee point calculating unit that calculates a knee point based on the maximum luminance value calculated by the maximum luminance value calculating unit and the proportion of the high luminance signal calculated by the high luminance proportion calculating unit; and a knee processing unit that generates a knee slope with a predetermined inclination starting at the knee point calculated by the knee point calculating unit, wherein the knee processing unit does not change the predetermined inclination, regardless of the value of the knee point calculated by the knee point calculating unit.