In this invention, for example, in order to realize conversion to "smooth skin"
and "wrinkle enhancement" with a natural look while preserving the grain and texture
of the skin, a specific amplitude band variation component separation type digital
filter (-filter), which comprises a specific amplitude band variation component
calculation section 4, is newly provided. Further, the calculation section
4 selectively separates only a specific amplitude band variation component
U (m, n) from an input image signal X (m, n) applied to the filter. An image signal
y (m, n), which is provided by subtracting the component from the input image signal
(conversion to "smooth skin") or by adding the component to the input image signal
("wrinkle enhancement"), is outputted in response to an external correction instruction.
