Research Of Acoustic Imaging System Based On The Spiral Array

Noise control problems receives more and more attention in recent years, noise detection is widely used in household appliance, automobiles, ships, aircraft, machinery manufacturing and other industries. It can reduce machine noise and detect equipment failure through noise source location and noise source separation. Many domestic and foreign experts have done a lot of theoretical research and application development work in the noise source detection and proposed a number of ways, such as near-field pressure level measurement, sound insulation selection, surface velocity measurements, acoustic holography. These methods all have their limitations. With the development of array processing technology, the use of microphone array for noise source identification becomes more developed. Array design and Algorithm Research are two key technologies of microphone array sound source localization. This article has carried on the theory research and simulation contrast, and design acoustic imaging system based on the spiral array.The research results in this thesis listed as follows:1. Basic Array signal theory had been studied, mathematical models of the signal arriving at array are analyzed. the narrowband of the output data of array with arbitrary geometry are given.2. The array structure influence on beam pattern the array is analyzed, and comparative simulation all kinds of regular array rule and Irregular arrays rules. By comparing, the beam direction of the optimized spiral array is best, side lobe level lower, and thus has better spatial resolution.3. Conventional beamforming algorithm is researched, the beam control and weighting influence on beam pattern is analyzed. And then introduce MVDR algorithm and MUSIC subspace algorithm, and give simulation comparison with the conventional beamforming algorithm.4. Introduce acoustic imaging positioning system based on the spiral array separately from the hardware system and software implementation and test various performance indicators. The experimental results indicate that the acoustic imaging system has high spatial resolution and strong capability of eliminating ghost images. It can be applied widely into many fields such as localization and separation of noise sources, machine condition monitoring, noise reduction...