GAMMA CORRECTION DEVICE AND GAMMA CORRECTION METHOD

The present invention relates to a gamma correction device and a gamma correction method. The gamma correction device comprises: a illumination sensor which senses external light; an illumination analysis unit which analyzes the illumination of the external light and outputs a selection signal; a gamma adjustment unit which adjusts a gamma curve according to the selection signal; and an image data conversion unit which corrects inputted image data based on the gamma curve. The illumination analysis unit outputs a first selection signal when the illumination of the external light is brighter than a first reference brightness, outputs a second selection signal when the illumination of the external light is darker than the first reference brightness and is brighter than a second reference brightness, and outputs a third selection signal when the illumination of the external light is darker than the second reference brightness. The gamma adjustment unit adjusts the gamma curve in response to the first and second selection signals. The gamma adjustment unit adjusts the gamma curve such that the output value for the input value has a sigmoid form. The gamma adjustment unit adjusts the gamma curve such that the slop of the output value for the input value gradually increases in response to the third selection signal.