Test device, display device, and method of generating compensation data for a display device

A method of generating information to control display of images providing a display device with align pattern data to which box data having a maximum reference gray level is added, obtaining a first capture image generated based on the align pattern data to which the box data is added, providing the display device with one or more full pattern data respectively having one or more reference gray levels lower than the maximum reference gray level, and obtaining one or more second capture images generated based on the one or more full pattern data. The method also includes generating compensation data including compensation values at the one or more reference gray levels and the maximum reference gray level. The compensation data may be generated based on the one or more second capture images and a portion of the first capture image corresponding to the box data.