Provided is an image processing method of processing first red, green, and blue (RGB) data with a display device including a pixel configured with red, green, blue, and white sub-pixels and providing the processed data. The method includes receiving the first RGB data, rendering the first RGB data to generate second RGB data and white (W) data, converting the first RGB data into hue, saturation, and value (HSV) data, obtaining RGB compensation data by using the HSV data on the basis of a lookup table, compensating for the second RGB data by using the RGB compensation data, and outputting the compensated second RGB data and the W data.