Video signal processing device and projection-type display device

A video signal processing device comprising:

• a black stripe detector to detect whether or not each pixel of an input video signal, in which a part of an effective region is a black stripe region, is a pixel included in the black stripe region, and to generate a black stripe identification signal;
• a signal combiner to combine the input video signal and the black stripe identification signal with each other to generate a combination signal;
• a keystone correction processor to implement keystone correction processing for the combination signal so as to correct a trapezoidal distortion when the input video signal is projected onto a screen, and to generate a keystone-corrected combination signal;
• a signal separator to separate the keystone-corrected combination signal into a keystone-corrected video signal subjected to the keystone correction processing and a keystone-corrected black stripe identification signal indicating whether or not each pixel of the keystone-corrected video signal is a pixel included in a black stripe region;
• and a video signal processor 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.