| 摘要 |
A method of detecting intrusion into a vehicle is disclosed which incorporates an ultrasonic wave generator (1, 2) and a detection system that amplifies and rectifies (4, 5) the signal received by a detector (3). The system uses fuzzy logic to analyse various aspects of the detected signal, such as its frequency content (using filters 6), power and duration, so as to detect variations in this signal. The fuzzy logic output, whose functionality is implemented using a microprocessor (7), may then be used to trigger an alarm. The advantages are that by using fuzzy logic the number of false alarms may be reduced, and that by using a microprocessor to implement the fuzzy logic the conditions which trigger the alarm may be altered without changing the hardware. |
