OBSTACLE APPROACH DETECTION METHOD AND ILLUMINATION DEVICE USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an obstacle approach detection method capable of easily detecting approach of an obstacle in multiple directions.SOLUTION: This obstacle approach detection method is an obstacle approach detection method for detecting approach of an obstacle in the neighborhood by using an annular backward light emission unit 2 arranged to face backward, an illumination reflection unit 3 arranged to face forward, reflecting light from the backward light emission unit 2, and providing illumination by reflected light, and an imaging device 4. The illumination reflection unit 3 includes a projecting curve portion 3a and a flat portion 3b provided around the projecting curve portion 3a. Reflected light reflected by the flat portion 3b out of reflected light rays forms an annular or partially annular high-illuminance irradiation area having high illuminance for an obstacle, the reflected light reflected by the projection curve portion 3a out of the reflection light rays forms a low-illuminance irradiation area lower in illuminance than the high-illuminance irradiation area. If an obstacle approaches in a preset alert distance, the illuminance of the high-illuminance irradiation area increases to change to illuminance equal to or higher than alert illuminance and the approach of the obstacle is detected.