This paper investigates real-time N-dimensional wideband sound source localization in outdoor (far-field) and lowdegree\r\nreverberation cases, using a simple N-microphone arrangement. Outdoor sound source localization in different\r\nclimates needs highly sensitive and high-performance microphones, which are very expensive. Reduction of the\r\nmicrophone count is our goal. Time delay estimation (TDE)-based methods are common for N-dimensional wideband\r\nsound source localization in outdoor cases using at least N + 1 microphones. These methods need numerical analysis\r\nto solve closed-form non-linear equations leading to large computational overheads and a good initial guess to avoid\r\nlocal minima. Combined TDE and intensity level difference or interaural level difference (ILD) methods can reduce\r\nmicrophone counts to two for indoor two-dimensional cases. However, ILD-based methods need only one dominant\r\nsource for accurate localization. Also, using a linear array, two mirror points are produced simultaneously (half-plane\r\nlocalization). We apply this method to outdoor cases and propose a novel approach for N-dimensional entire-space\r\noutdoor far-field and low reverberation localization of a dominant wideband sound source using TDE, ILD, and headrelated\r\ntransfer function (HRTF) simultaneously and only N microphones. Our proposed TDE-ILD-HRTF method tries to\r\nsolve the mentioned problems using source counting, noise reduction using spectral subtraction, and HRTF. A special\r\nreflector is designed to avoid mirror points and source counting used to make sure that only one dominant source is\r\nactive in the localization area. The simple microphone arrangement used leads to linearization of the non-linear closedform\r\nequations as well as no need for initial guess. Experimental results indicate that our implemented method features\r\nless than 0.2 degree error for angle of arrival and less than 10% error for three-dimensional location finding as well as\r\nless than 150-ms processing time for localization of a typical wideband sound source such as a flying object (helicopter).
Loading....