In recent years, on-board information display equipment, including navigation systems, has been rapidly spreading. On the other hand, with the increasing number of elderly drivers, such displays as easy to see for elderly drivers are desired. In this paper, we propose a new approach to designing visual displays based on a human vision model. The proposed method is implemented by image processing techniques, which are intended to compensate the deterioration of human vision with age using visual properties; the spatial sensitivity of eyes, the spectral transmittance of crystalline lens. Images are processed by sharpening edges and by changing color balance, and the optimum character size is determined based on the human visual properties. The validity of the method was confirmed by measuring the minimum legible character size. We demonstrate the results applied to navigation images.
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