Patent ID: 7221806

Claim:
An image processing method for obtaining a processed image signal from an original image signal representing an original image having a certain resolution, in which a plurality of intermediate image signals which are different in frequency band are made on the basis of the original image signal, a plurality of transformed image signals are obtained by carrying out a transformation processing on the respective intermediate image signals on the basis of transformation functions which are set according to the frequency bands of the respective intermediate image signals, and a processed image signal is obtained from the transformed image signals, wherein the improvement comprises the steps of preparing reference transformation functions for transforming the intermediate image signals obtained from a reference original image signal representing a reference original image having a reference resolution which are set according to the frequency bands of the respective intermediate image signals, and, when an object original image signal to be processed represents an original image having a resolution lower than the reference resolution, setting the transformation functions for transforming the intermediate image signals obtained from the object original image signal to be equal to the respective reference transformation functions for the intermediate image signals in the frequency bands not higher than the frequency band corresponding to the resolution of the original image represented by the object original image signal.