Object detection apparatus employing electro-optics

摘要: Apparatus for detecting the presence of an object within area under surveillance employs electro-optical emitter directing light into and receiver sensing reflected from which originates emitter. The emits energy a preselected wavelength is modulated at frequency to provide emanating with characteristic signature. Light by filtered converted electrical signal varies in accordance magnitude having modulation frequency. A selected portion amplified band-pass amplifier synchronously sampled determine originated compared threshold value whether present surveillance. are covered transparent shield protect them against foreign matter. An detector monitors accumulation particulates on shield. apparatus may be desirably used vehicles detect adjacent objects, particularly vehicle's "blind spots" thereby avoid collisions.