A display characterization system may be used to gather display flatness data and light leakage data from a display. The display characterization system may include a camera system that includes flatness measurement cameras and a light leakage measurement camera. The camera system may include a light guide plate covered with a patterned opaque layer or other planar light-emitting structures for emitting patterned light that is reflected from the display. A controller may use the light leakage measurement camera to capture light leakage data while a display backlight unit is on, a reference light source is on, and the planar light-emitting structures are not emitting light. The controller may use the flatness measurement cameras to capture flatness data while the backlight unit is off, the reference light source is off, and the light-emitting structures are reflecting light from the display.