Canon Kabushiki Kaisha

Yuuki Shindo

Izumi Kanai

Tetsuji Saito

Taisuke Nishio

An image processing apparatus includes a histogram creation unit that creates a histogram from an input image, a detection unit that detects a gradation level of interest from the histogram, a gradation correction parameter generation unit that generates a gradation correction parameter to improve a gradation characteristic in a gradation range around the gradation level of interest, and a correction unit that corrects the gradation of the image using the gradation correction parameter. The detection unit detects, as the gradation level of interest, a gradation level whose frequency is a peak value equal to or more than a predetermined threshold, and which has variation width of frequencies in a predetermined range including this gradation level to be smaller than a predetermined width in the histogram.

Image processing apparatus and control method thereof detecting from a histogram a gradation level whose frequency is a peak value

An image processing apparatus according to the present invention extracts a characteristic value of a luminance in relation to respective fields of an input video, and determines the presence of a scene change between adjacent fields. A gamma curve is then generated on the basis of the magnitude of the characteristic value. When a difference in the characteristic value between fields is larger than a predetermined value and a scene change does not exist, the gamma curve to be applied to a subsequent field is modified such that the correction characteristic of the gamma curve does not vary rapidly. The luminance is then corrected using the modified gamma curve.

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Yokohama, Japan

Yuuki Shindo