The invention relates to a method and a device for generating a virtual installation model as an image of a real installation. A first scale has marks spaced at 14 inch intervals for making blocks for studs, and a second scale has marks spaced at 22 inch intervals for making blocks for rafters. The optical system as well as the image processing system provides for relatively increased discrimination of headlamps and tail lamps of other vehicles and also enables the high beam headlamps of the control vehicle to be controlled as a function of the distance as well as horizontal angular position of other vehicles relative to the controlled vehicle.