A black stripe detector is configured to detect whether or not each pixel of an input video signal is a pixel in a black stripe region, and to generate a black stripe identification signal. A signal combiner is configured to combine the input video signal and the black stripe identification signal with each other to generate a combination signal. A keystone correction processor is configured to implement keystone correction processing for the combination signal, and to generate a keystone-corrected video signal. A signal separator is configured to separate the keystone-corrected combination signal into a keystone-corrected video signal and a keystone-corrected black stripe identification signal. A video signal processor is configured to implement predetermined video signal processing for the keystone-corrected video signal by using the keystone-corrected video signal and the keystone-corrected black stripe signal.