| 摘要 |
A car reversal radar includes a CPU having predetermined compensation values and a threshold distance. When the car reversal radar starts, its surrounding environment is recorded into an initial detecting value. The initial detecting value is compared with a subsequent detecting value recorded for the environment when the car is being backed. When the subsequent detecting value is greater than the sum of the initial detecting value and the compensation value, the distance between an obstacle and the ultrasonic sensors on both sides at the back of the car is compared with the threshold distance. If the former is greater than the latter, the compensation value is increased. Therefore, the obstacle has to approach the ultrasonic sensor even closer in order to activate an alarm, because the sensitivity of the ultrasonic sensors at the tail is reduced. So, incorrect actions are prevented. |
