| In recent years,sound source localization(SSL)technology based on microphone array(MA)has gradually become a research hotspot with the rapid development of the speech interaction market.SSL technology based on MA is a powerful means to achieve speech enhancement and noise removal,which is widely available for smart homes,conference systems,industrial noise detection sniper and other major fields.However,most of the current localization systems are based on PC platform to process data and realize localization,which has the disadvantages of large volume and low integration.And the traditional SSL algorithms need to be further improved because the application environment is often accompanied by noise and reverberation.In this thesis,a SSL system based on small MA and the ZYNQ platform is proposed to solve the problems raised above.The SSL algorithm is improved based on the TDOA,which is a two-step localization method of time delay estimation(TDE)before localization estimation.The main contributions in this thesis are as follows.(1)The processing method of speech data is introduced theoretically and the parameters affecting the performance of MA are simulated and analyzed.In order to facilitate the subsequent algorithm to process the speech signal,the speech framing,windowing and activity detection methods are expounded.The factors affecting the performance of MA are simulated and analyzed based on the CBF algorithm,which provides ideas for designing MA later.(2)Propose an improved TDE algorithm to solve the problem of poor performance of the traditional algorithm under the conditions of reverberation and low signal-to-noise ratio.The IMAGE reverberation model is established firstly,and the common weighting functions of the traditional algorithm are simulated.An improved TDE algorithm based on PHAT weighted and second cross correlation is proposed.The results of simulation in the IMAGE reverberation model prove that the root mean square error of the improved TDE algorithm under the conditions of reverberation and low signal-to-noise ratio is lower than that of the traditional TDE algorithm.(3)Design the localization algorithm according to the least squares method to solve the problem that the TDE error of TDOA algorithm in position estimation is easy to be amplified.This thesis first establishes a multi-baseline localization model and determines the MA geometry.After deriving the equation system between the localization parameter,the TDE value and error,the iterative algorithm is designed based on the least squares method.Finally,the mean square error and the Cramer-Rao Lower Bound(CRLB)of the localization algorithm are derived,and it is proved that the accuracy of angle estimation is close to CRLB.(4)Design and complete the SSL system based on the ZYNQ platform.Firstly,the hardware design of MA and its interface are carried out,then the multi-channel speech data processing and TDE are designed in the PL part.In order to input the time delay value into the PS part for angle calculation,the communication system between the PL and PS part is designed and implemented.Finally,the localization algorithm is implemented in the PS part and the angle of speech are output.The test results of the SSL system show that the system takes an average of 23.47 ms to complete a single localization,and the average absolute error of the azimuth and elevation angles do not exceed 3° within a range of 3 meters,which meets the requirements of the parameter indicators.The advantages of SSL system in real-time localization and accuracy are verified compared with the relevant literatures. |
