Motor Vehicle Whistling Sound Monitoring Based On Microphone Array

With the rapid development of national economy,urban vehicle inventory has been growing year by year.A large number of motor vehicle horns have brought great harm to physical and mental health,traffic safety,humanity and natural environment.In recent years,the punishment to illegal whistling has been strengthened.How to apply intelligent research and technology of sound to the detection,identification and localization of motor vehicle horns,and how to improve the accuracy are hot and difficult issues.The high cost of illegal horn snapping system makes it difficult to popularize.To solve these problems,a low-cost data acquisition system based on microphone array is designed.The system uses a high-performance microchip of STM32F4 family as MCU,which can complete the function of real-time audio data acquisition and storage.It also has the advantages of miniaturization and easy operation.Based on the audio data acquisition system,focusing on the detection of motor vehicle horns in noisy environment,the dissertation optimized the algorithms to make up for the shortcomings of cost reduction.Therefore,after studying the characteristics of motor vehicle horns,this dissertation applied a generalized sidelobe canceller based adaptive enhancement technique to suppress the complex noise in the horn forbidden area,providing a more pure motor vehicle horns and improving detection performance.At the same time,the detection algorithm of motor vehicle horn based on the wavelet packet energy spectrum has been studied and improved.Finally,this dissertation evaluated the performance of the algorithm,showing that the detection algorithm of motor vehicle horn based on wavelet packet has a low miss detection rate.However,with the decrease of signal to noise ratio(SNR),the interference effect of noises increase.The adaptive enhancement algorithm can suppress noises more effectively.Also,most identifiable features of vehicle horn sound are retained.