| 摘要 |
A method of and apparatus for counting objects present within a predetermined area, by detecting acceleration and deceleration of the objects employ at least one Doppler radar to sense the movements of the objects by monitoring the Doppler frequencies of signals reflected from the objects, amplifying the Doppler signal reflected from each of the objects to provide an amplified signal, effecting an automatic gain control of the amplified signal to provide a signal of substantially constant strength independent of the distance and size of the respective object, detecting a frequency variation of the constant strength signal as an indication of change in the speed of movement of a respective one of the objects, determining whether the constant strength signal represents an acceleration or deceleration of the respective object, and correspondingly modifying a count representing the number of the objects in the predetermined area. |
