Study On Target Sound Recognition System Based On Auditory Bionics

The recognition technology of target sound is one of the important branches ofacoustics recognition, whose development improves peoples' working efficiency,quality of living and service quality greatly. But because of wider range of sound, it isvery difficult to do accurate matching for sound recognition system, and recognitioneffect is also easy to be reduced by the influence of volume, acoustics, velocity andbackground noise. Therefore, it is essential to study and design the recognition systemof target sound with high recognition rate and high robustness.With further study of audio signal processing, it is found that the human'sauditory system has an unique superiority in listening and distinguishing, which canextract feature of target sound accurately and recognize the direction, category andcontent precisely. And the target sound recognition based on the ear bionic isincreasingly concerned. Therefore, the target sound recognition based on the audiobionic is studied systematically in this paper, and the ear bionic theory, featureextraction technologies, target sound classification technology and hardwareimplementation of recognition system based on FPGA are explored actively. Allresearch works in the paper are outlined as following:1. Through analyzing the physiological structure of auditory system andperception process, a comparatively complete mathematical model of auditory systemis studied and established, which simulates the sound treatment processing. Thesimulation experiment shows that the mathematical model can commendably simulatethe frequency division and filtering of the basilar membrane of cochlea and theprocess of energy transition of inner hair cells. 2. Through analyzing and comparing with usual methods of audio featureextraction, in the light of the commonly existing problems of poor robustness, anaudio feature extraction based on auditory spectrum is proposed. This methodprocesses signal by using the mathematical model of auditory system, which canaccord with the treatment process of ear, extract audio feature well, avoid losing thekey information and improve the anti-noise performance and the recognition rate ofthe system.3. Through studying the comparison with usual methods of pattern recognition,considering nonlinear algorithm of sound, BP Neural Network which has higheradaptability, direct form and clear mathematic significance is chosen in this paper torecognize and classify the target sound. The simulation experiment shows that theaverage recognition rate of all test samples by using BP Neural Network reaches93.14%, which suggests that it is an effectual method to classify and recognize thefeatures of target sound.4. Based on mathematical model of auditory system, auditory spectrum methodand BP Neural Network, considering the complexity of algorithm, hardware resourcesand interface etc, the hardware design of target sound reorganization by using FPGAembedded development platform is proposed in this paper. The hardware systemsimulates the frequency division of the basilar membrane of cochlea and designs thefilter of basilar membrane by using VHDL (hardware description language), andrealizes the mathematical model of inner hair cells and cochlear nucleus, as well asfeature extraction method based on auditory spectrum and FPGA hardwareimplementation of BP Neural Network. Finally, the five chosen different sounds,cannon, ambulance, steamship, train and aircraft taxiing as examples, are recognizedrepeatedly in target sound system based on FPGA. The test results show that therecognition rate for the sound samples of ambulance is maximum,97.14%, however,the recognition rate of cannon in testing sample is the minimum,85.71%. The averagerecognition rate of all testing sample reaches91.43%. The research results show thatthe auditory bionic system based on FPGA hardware implementation is effective insound recognition and the scheme is feasible.Auditory bionics technology and FPGA hardware technology are applied totarget sound recognition system successfully in this paper, which provide theoreticalsupport and technical reference for the study of relevant technology and engineeringpractice.