Maximum-Likelihood Estimation of Recording Position Based on Audio Watermarking

In this paper, we propose a maximum-likelihood method for estimating a recording position inside several loudspeakers as a brand-new application of digital audio watermarking, which could be useful for protecting from illegal recordings of movies. An error model of times of arrival (TOAs) is utilized to estimate the recording position. The error model is constructed based on watermarking strengths, which are calculated by a watermark detection algorithm. This enables us to estimate the position if some of the TOAs are accurately measured. Experimental results indicate that the algorithm can estimate the recording position with the mean value of errors of 0.81 m.