Method and unit for suppressing a periodic pattern

A periodic-pattern suppression method of reducing a spatial frequency component resulting from a stationary grid, contained in an original image signal photographed using said stationary grid, said method comprising the steps of:

• transforming said original image signal, represented in a real space domain, into a plurality of transformed image signals which can be handled in a frequency domain;
• and
• reducing a transformed image signal of said transformed image signals which has a desired frequency range containing a spatial frequency component corresponding to at least a grid array frequency of said stationary grid in only the vicinity of a grid array direction of said stationary grid.

A periodic-pattern suppression unit for reducing a spatial frequency component which forms a periodic pattern contained in an original image signal, said unit comprising the steps of:

• image signal transformation means for transforming said original image signal, represented in a real space domain, into a plurality of transformed image signals which can be handled in a frequency domain;
• and
• periodic-pattern-component suppression means for reducing a transformed image signal of said transformed image signals which has a desired frequency range containing a spatial frequency component corresponding to at least a frequency of said periodic pattern in only the vicinity of an array direction of said periodic pattern.

A periodic-pattern suppression unit for reducing a spatial frequency component resulting from a stationary grid, contained in an original image signal photographed using said stationary grid, said unit comprising:

• image signal transforming means for transforming said original image signal, represented in a real space domain, into a plurality of transformed image signals which can be handled in a frequency domain;
• and
• stationary grid-component suppressing means for reducing a transformed image signal of said transformed image signals which has a desired frequency range containing a spatial frequency component corresponding to at least a grid array frequency of said stationary grid in only the vicinity of a grid array direction of said stationary grid.