No abstract

The geometry of an enclosure is of interest for example when synthesizing impulse responses or when studying concert halls. Recently, several approaches for estimation of the room geometry, or the reflective surfaces, have been proposed. These approaches use a priori information of the source signal for the room geometry estimation, typically, impulse response measurements. Here, a method for estimating the reflective surfaces from continuous signals, such as speech or music, is proposed. The method is based on inverse mapping of the acoustic multi-path propagation problem. The validity of the method is demonstrated in a real auditorium. With reasonable signal-to-noise ratio the proposed algorithm has less than 0.05 m error in the position of the point of reflection and less than 1 degree of error in the direction of the normal of the surface.

The characteristics of early reflections have a major effect on the acoustics of concert halls. In this article a framework for automatic localization of reflections and their properties is formulated. The framework uses impulse responses measured with multiple microphones. The focus is on the methods that can be used for detecting reflections and the methods that estimate the direction of arrival. Three methods for both tasks are given and their performance is measured using simulated data. Finally an example in a real auditorium is shown using the most reliable methods for detecting and estimating the direction of arrival of the reflections.

Recently, the need of monitoring parking places, airports, and harbours has increased. Microwaves, infrared based techniques, vision, or acoustics are the key techniques but each of them requires a specific kind of postprocessing. Far field target localization methods based on Angle Of Arrival (AOA) often neglect the possibility of erroneous angle observations. Three different methods for increasing the accuracy of cross fixing based localization are compared. Average of the AOAs is easily corrupted by outliers, "m out of k"-selection of AOAs suffers from loss of data. Signal energy based target location circle is used to validate the cross fixing result, thus improving reliability. The energies of averaged target signals from two arrays are used to calculate a circle on which the target resides. Distance from the cross fixed location to the circle is used to validate the location. Experiments are carried out with simulated and real data.

No abstract