Patent ID: 9638797
Date: 2017-05-02
CPC Classifications: G01S,G08B

Claim:
1. A monitoring device for monitoring a first object, comprising: M emitters, wherein M is a positive integer, and the emitters are capable of being driven to emit waves with directivity; and N receivers, wherein N is a positive integer, and the receivers are disposed corresponding to the emitters and each used for receiving the wave emitted from the corresponding one of the emitters; wherein transmitting paths of the waves define a monitoring area, and when the waves are reflected by the first object within the monitoring area and received by the corresponding receivers, a moving trend of the first object with respect to the monitoring area is determined by a quantity change of the receivers receiving the reflected waves, and wherein the moving trend of the first object is determined as a leaving trend from the monitoring area when the quantity change of the receivers receiving the reflected waves is in a gradually decreasing trend of consecutive integers.