The present invention relates to an automatic test system for a digital display system, which digital display system comprises display electronics configured to output a digital video stream, and a display screen connected to the display electronics to receive the digital video stream generated thereby and to display at least one image based on the received digital video stream. The automatic test system is designed to be connected to the digital display system to receive the digital video stream generated by the display electronics, and is configured to: reconstruct in memory an image based on the received digital video stream; compute a signature of the reconstructed-in-memory image; and test the digital display system by comparing the computed signature with a reference signature so as to thereby check whether the reconstructed-in-memory image completely matches an expected good display behavior, wherein said reference signature is indicative of said expected good display behavior.