Embodiments related to the calibration of an optical touch-sensitive display device are disclosed. For example, one disclosed embodiment comprises a method of calibrating an image sensor, wherein the method comprises placing a photoluminescent panel over the display surface, and illuminating a target location on the display surface with visible light. Infrared light that is emitted by the panel in response to the illumination of the display surface is received via the image sensor. The received light then is used to calibrate the device.