| 摘要 |
PURPOSE:To reduce a dead angle and an unnecessary detection range and to make it possible to easily set an detection range with an arbitary shape, by properly setting the detected distance corresponding to a divided azimuth angle range so as to obtain a desired detection range. CONSTITUTION:Matter M to be detected is detected on the basis of the time delay of the reflected wave by the matter M to be detected of an intermittently emitted ultrasonic pulse. The azimuth angle range of the reflected wave to be detected is divided by the azimuth angles theta1-theta4 set by the azimuth angle gate setting circuit 20 of a division discrimination means 4, and for example, four divided azimuth angle ranges are respectively set left and right and AND circuits 22a-22d judges the azimuth angle ranges of receiving signals obtained from the reflected waves. The outputs of these circuits 22a-22d are inputted to the distance gates 3a-3d of a detection range setting means 3 and AND circuits 24a-24d discriminates whether said outputs are in detection distances l1-l4 respectively set at every divided azimuth angle ranges. When either one of the outputs of the circuits 24a-24d was obtained, a matter detection signal is outputted from a detection signal forming circuit 5. |
