A spatial maximum value filter generates a low frequency video signal in an intermittent frame by removing high frequency components from a video signal in the intermittent frame. A division signal extraction unit calculates a ratio of a signal value of a video signal in an acquired frame to a signal value of a low frequency video signal in an intermittent frame closest to the acquired frame, and generates a high frequency video signal having the calculated ratio as a signal value. A signal adjustment unit calculates a ratio of a signal value of the video signal in the intermittent frame to a signal value of a high frequency video signal in the intermittent frame, and generates an adjusted low frequency video signal having the calculated ratio as a signal value.