An
image processing device compensates an original image for helping deteriorated human vision characteristics and displays the compensated image. Declines in a
spectral sensitivity characteristic is compensated for by multiplying a brightness value of the original image by an inverse characteristic 1 / A of a relative
spectral sensitivity characteristic A in reference to a predetermined
spectral sensitivity characteristic of a standard person. The first compensated image q(x,y) for defocus, or declines in
accommodation characteristic, is obtained by a
convolution integral of an original input image f(x,y) and a function j(x,y). The second compensated image m(x,y) for declines in sensitivity to
cut-off frequency is obtained by a
convolution integral of an original input image q(x,y) and the function p(x,y). The j and the p vary utilizing a
radius of a blurred image and the
cut-off frequency as a parameter, respectively. The
image processing device enables an observer to recognize the original image as it is or as observed by the standard person, regardless of age or individual variations.