1. An image compensating device comprising: compensation means for compensating for an original image based on a human vision characteristic of an observer of the image, and upon a predetermined standard vision characteristic which is a vision characteristic of a human visual system other than that of the observer and at a standard age which is independent of the age of the observer; and display means for displaying a compensated image by said compensation means, wherein said compensation means compensates an original image such that a compensated image observed by the observer is substantially equal to the original image observed by a standard person of the standard age, said compensation means compensates an original image based on a spatial frequency characteristic of contrast sensitivity of a human visual system, and said compensation means compensates an original image based on a wavelength characteristic of contrast sensitivity for a human visual system, wherein said compensation means compensates said original image based on a standard sensitivity wavelength characteristic .alpha..sub.0 (.lambda.) of said standard person and a sensitivity wavelength characteristic .alpha..sub.x (.lambda.) of said observer of age x, where .alpha..sub.0 (.lambda.) is defined as a ratio of an incident light spectral distribution I(.lambda.) to a recognition light spectral distribution O.sub.0 (.lambda.) of said standard person and said .alpha..sub.x (.lambda.) is defined as a ratio of said I(.lambda.) to a recognition light spectral distribution O.sub.x (.lambda.) of said observer.