An imaging device includes an image obtaining unit configured to capture an image of a subject to obtain video data; an extraction unit configured to extract high-frequency components in at least one of a horizontal direction and a vertical direction of the video data; a calculation unit configured to calculate a parameter based on the high-frequency components in the at least one of the horizontal direction and vertical direction extracted by the extraction unit, the parameter indicating a magnitude of a high-frequency component for every line or every group of lines in the at least one of the horizontal direction and vertical direction; and a combining unit configured to combine an indicator indicating a magnitude of the parameter with the video data at a predetermined position in the at least one of the horizontal direction and vertical direction.