Apparatus for gamma correcting image data

In an apparatus for gamma correcting image data including a first image data, a second image data and a third image data, the apparatus includes: a first clock generator for generating a first clock; a second clock generator for generating a second clock, wherein the second clock has a frequency a predetermined times as fast as the first clock; an image data input unit for storing the image data in response to a first clock; a first selecting unit for selectively outputting the image data in response to a second clock; a second selecting unit for selectively outputting a starting point value of corresponding image data in response to the second clock; a third selecting unit for selectively outputting a gamma slope value of corresponding image data in response to the second clock; a piecewise gamma correction unit for receiving output values from the first, the second and the third selecting unit to generate gamma corrected image data; and an output unit for storing the gamma corrected image data a predetermined time and outputting the gamma corrected image data in response to the second clock.