| 摘要 |
PURPOSE:To obtain an inexpensive device which is simple in its structure and can be made small-sized, by installing two recurrent passive reflectors at a constant interval to the rear of a car, irradiating a light to the two passive reflectors, and applying triangulation by the light. CONSTITUTION:Two recurrent passive reflectors are installed at a constant interval to the rear of a car, and a light is irradiated to the two passive reflectors, so that a reflected light forms an image on an image position detecting element through a lens. Subsequently, a distance of two images on the image position detecting element is measured, and in accordance with its measured distance, an intercar distance to a car to which the passive reflectors have been installed is operated and detected. For instance, it is constituted so that reflected rays of light from recurrent passive reflectors installed to the rear of a car pass through a lens 2, and images 4 are formed on an image position detecting element 3. Also, an output of the image position detecting element 3 is supplied to a start- stop signal generator through a comparator 6, and the intercar distance is calculated and displayed by an operating circuit together with a counting value by a counter 7. |
