Patent ID: 8913194

Claim:
An image processing apparatus comprising: a luminance sensor to sense a brightness of an external light; a contrast calculation unit to calculate a contrast value of the input image by calculating the contrast of the input image as a slope of a line connecting points at which a cumulative distribution function meets a low range threshold value and a high range threshold value, respectively; a model storage unit to store a luminance-contrast model curve representing an optimal contrast value for a particular luminance of each brightness of the external light; a luminance-contrast adjustment unit to determine a target luminance value according to the sensed brightness of the external light, to obtain a contrast value corresponding to the target luminance value with reference to the luminance-contrast model curve corresponding to the sensed brightness of the external light, and to adjust an input image to have the target luminance value and the obtained contrast value; and a saturation adjustment unit to adjust the saturation of the adjusted input image by increasing the saturation of the input image when the luminance and the contrast of the input image are increased by the luminance-contrast adjustment unit, and by decreasing the saturation of the input image when the luminance and the contrast of the input image are decreased by the luminance-contrast adjustment unit.