| 摘要 |
PURPOSE: A method for filtering a receiving signal of an obstacle sensing system is provided to make an irregular alarm signal orderly by keeping a constant measurement distance. CONSTITUTION: A counter is reset(S1). An ultrasonic wave is inputted from an ultrasonic wave sensor module(S2). A process determines whether the value of the counter is "0" or not(S3). If the value of the counter is "0" , the process determines whether the size of the inputted ultrasonic wave signal is "0" or not(S4). If the result is not "0", the process determines the inputted ultrasonic wave signal to a present ultrasonic wave signal(S5). The process determines whether the present counter value is "4" or not(S6). If the counter value is not "4", the process increase the counter value by "1"(S7) and then proceeds to the determination procedure(S2). Otherwise, if the counter value is not "0" at the determination procedure(S3), the process determines whether the inputted ultrasonic wave signal again is smaller than the former ultrasonic wave signal or not(S8). If the result is positive, the process proceed to the determination procedure(S5). If the size of the inputted signal is "0" and the inputted ultrasonic wave signal again is not smaller than the former ultrasonic wave signal, the process determines the former ultrasonic wave signal to the present ultrasonic wave signal and then proceeds to the determination procedure(S6).
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