Method of displaying character and symbol in on-board display

The given time to look at an on-board display in a car is so limited from the viewpoint of safe driving. Hence, visibility of the on-board display should be more excellent than the ordinary display. This report describes an appropriate method for displaying characters and symbols with an automotive display. Under the condition of a constant surrounding illuminance, the visibility of characters and symbols depends on the character complexity and the viewing distance. In this method, the character complexity is represented by the two dimensional frequency (linear density), which is associated with the driver's visual acuity and the viewing distance. Then, the appropriate character size is determined based on the spatial frequency properties. Experiments show that this method was very effective on improving the display visibility.