There is described an image processing method and an image converting apparatus for performing the image processing for recording the medical image information. The apparatus includes an image converting section to convert the image in respect to the original image signals; an image feature extracting section to extract image features for every pixel included in the plurality of pixels in respect to the original image signals; a sharpness information obtaining section to obtain sharpness information from the image converting section; a sharpness calculating section to calculate correlation between the image features and the sharpness information; and a frequency processing section to compensate for a sharpness level of the image, based on the correlation calculated by the sharpness calculating section, so as to reduce a variation of the sharpness level before and after the image converting section converts the image in respect to the original image signals.