Patent ID: 8744207

Claim:
An image processing device comprising: an original image inputting unit that receives an input of an original image for which image processing is performed; a local area setting unit that sets a local area around a pixel for which lightness is converted, in the original image; an upper limit conversion function setting unit that sets an upper limit conversion function which continuously and monotonically increases with respect to the lightness, and determines an output upper limit of lightness conversion; a lower limit conversion function setting unit that sets a lower limit conversion function which continuously and monotonically increases with respect to the lightness, and determines an output lower limit of lightness conversion; an upper limit/lower limit calculating unit that calculates an upper limit value which is a value of the upper limit conversion function of lightness of the pixel to be converted and a lower limit value which is a value of the lower limit conversion function; a ratio calculating unit that calculates a ratio for setting a value between the upper limit value and the lower limit value according to lightness of each pixel in the local area; and a lightness calculating unit that calculates converted lightness of a pixel for which the lightness is converted, based on the upper limit value, the lower limit value and the ratio.