STATISTICAL MODELS FOR CONSTANT FALSE-ALARM RATE THRESHOLD ESTIMATION IN SOUND SOURCE DETECTION SYSTEMS

• Main Author: Saghaian Nejad Esfahani, Sayed Mahdi
• Format: Others
• Published: UKnowledge 2010
• Subjects: Sound Source Localization; CFAR Processor; High-pass Filter; Chi-square Distribution; Weibull Distribution; Electrical and Computer Engineering
• Online Access: http://uknowledge.uky.edu/gradschool_theses/46; http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1045&context=gradschool_theses

Constant False Alarm Rate (CFAR) Processors are important for applications where thousands of detection tests are made per second, such as in radar. This thesis introduces a new method for CFAR threshold estimation that is particularly applicable to sound source detection with distributed microphone systems. The novel CFAR Processor exploits the near symmetry about 0 for the acoustic pixel values created by steered-response coherent power in conjunction with a partial whitening preprocessor to estimate thresholds for positive values, which represent potential targets. To remove the low frequency components responsible for degrading CFAR performance, fixed and adaptive high-pass filters are applied. A relation is proposed and it tested the minimum high-pass cut-off frequency and the microphone geometry. Experimental results for linear, perimeter and planar arrays illustrate that for desired false alarm (FA) probabilities ranging from 10-1 and 10-6, a good CFAR performance can be achieved by modeling the coherent power with Chi-square and Weibull distributions and the ratio of desired over experimental FA probabilities can be limited within an order of magnitude.