| 摘要 |
A method and apparatus for detection of opaque members when within a detection space which includes the steps of sequentially effecting a radiant energy transmission across a detection space from a plurality of spaced apart sources and causing a detection observed signal when such transmission is not sufficiently detected at each of a plurality of correspondingly located and sequentially correspondingly selected locations. There are means provided to in addition detect if there is a stray source of radiant energy and there are means to interface this with power machinery, such as an industrial press or guillotine. |
