High frequency emphasis amount control device

A high frequency emphasis amount control device comprising:

• a processor and memory storing instructions, the processor configured to execute the instructions to perform operations comprising:
• generating a first frequency spectrum by performing a two-dimensional discrete Fourier transform of an input image signal;
• generating a second frequency spectrum by performing a two-dimensional discrete Fourier transform of an output image signal output from a high frequency emphasis circuit;
• determining a first high frequency component index indicating a total amount of high frequency components based on the first frequency spectrum;
• determining a second high frequency component index indicating a total amount of high frequency components based on the second frequency spectrum;
• calculating a high frequency component emphasis ratio based on a ratio between the first high frequency component index and the second high frequency component index;
• and
• controlling an emphasis amount control value to the high frequency emphasis circuit, wherein the emphasis amount is increased when the high frequency component emphasis ratio is smaller than a target emphasis ratio,
• and the emphasis amount is decreased when the high frequency component emphasis ratio is larger than the target emphasis ratio, and the emphasis amount is maintained when the high frequency component emphasis ratio coincides with the target emphasis ratio.