A New Statistical Measure of Signal Similarity

A new measure of similarity, suitable for both signal processing and image processing applications, is presented. The measure of similarity ( Z
_M
) is an F-distributed test statistic that quantifies the degree of alignment, correlation or coincidence between two or more (time-or space-dependent) waveforms. The test statistic may be used to automate detection, classification, localisation, association and registration operations. When used to estimate time-of-arrival differences, which is typically done using cross correlation or beam formation, the technique provides an efficient means of: maintaining a low and constant false-alarm rate, detecting weak signals in noise and reducing angular errors. The method is applied to the problem of acoustic source detection and localisation. Real data are used to compare the method with cross correlation and normalised cross correlation. The new method yields prominent and narrow peaks, at the true source locations, with false peaks due to misalignment, misassociation, and background noise, suppressed. When processing continuous data streams, the test statistic is computed efficiently in the time domain.