IMAGE ENHANCING DEVICE, IMAGE ENHANCEMENT METHOD, IMAGE ENHANCEMENT PROGRAM, AND SIGNAL PROCESSING DEVICE

摘要

An object of the present invention is to improve quality of image by sufficiently sharpening the image through an appropriate high-frequency compensation with a simple arrangement, not only for still images but also for moving images and even if the images have already undergone image enlarging processes. An HPF (11) extracts high-frequency components from an input image signal Sin. A square operator (12) generates a squared signal S12 by squaring the first signal S1. A first differentiator (13) generates a first differentiation signal S13 by differentiating the squared signal S12. The second differentiator (14) generates a second differentiation signal S14 by differentiating the input image signal Sin. A multiplier (15) generates a second signal S2 by multiplying the first differentiation signal S13 by the second differentiation signal S14. An adder (16) generates an output image signal Sout by adding the second signal S2 to the input image signal Sin, as a compensation signal.