1. A display device comprising:a display which is configured to display an image;
a storage unit which is configured to store a contrast ratio at a center of the display;
a sensor which is attached to a periphery of the display so as to measure luminance in the periphery of the display by changing the luminance of the display from black luminance to white luminance, thus producing a plurality of measure values; and
a signal processing unit is configured to correct the plurality of measured values based on the contrast ratio so as to calculate a plurality of corrected measured values,
wherein the plurality of corrected measured values are calculated based on the plurality of measured values and a predetermined black luminance which is a maximum value, among the plurality of measured values, divided by the contrast ratio.