| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that when an object to be detected exists near an ultrasonic sensor, a direct wave and a reflected wave reflected from the object overlap, making it impossible to detect the overlapping wave as a reflected wave.SOLUTION: The width of an ultrasonic wave originated from an ultrasonic sensor is compared with that of a received ultrasonic wave, and it is determined that a direct wave and a reflected wave are overlapped when the width of the received ultrasonic wave is wider than the width of the originated ultrasonic wave and it is detected that the object is in the neighborhood. Furthermore, when it is determined that a direct wave and a reflected wave are overlapped, the width of an originated ultrasonic wave or a threshold used to reshape the waveform of a received ultrasonic wave is altered, thereby making it possible to acquire the direct wave and the reflected wave separately.SELECTED DRAWING: Figure 6 |
