The Closed Space Acoustics Fingerprint Construction Based On The Research On The Impulse Response

Space acoustic fingerprint of an enclosed space is a collection of various acousticparameters representing the geometric and acoustic properties of the enclosedspace, it isthe natural watermark of an audio file, and can be applied to copyright protection,judicial, criminal investigation, anti-spyware, anti-terrorism and other aspects. If we canextract the space acoustic fingerprint from the obtained audio signal, then we candeduce the environmental characteristics of the recording site, which will play animportant role in audio file identification, criminal case detection and judgment. Bystudying the construction of the space acoustic fingerprint, as well as its relationsbetween the size and internal acoustic characteristics of the enclosed space, it is possibleto infer the environmental characteristics of the recording space according to only apiece of audio signal.The impulse response function of the closed space reflects not only the acousticseffect of the space, but also the the geometric and acoustic properties of the space, i.e.the size, the structure and inner wall’s acoustic characteristics of the space, therefore, allof the parameters of an enclosed space’s acoustic fingerprint can be extracted itsimpulse response function.One of the most important parameter of an enclosed space’s acoustic fingerprint isthe reverberation time of the enclosed space. Based on the feasibility analysis of theconstruction of space acoustic fingerprint, we focused on mainly the estimation ofreverberation time. Since the impulse response function depends on the locations of thesound source and the receiver, Schroeder’s method of the reverberation time estimationfrom impulse response function will also be subject to the influence of the sound sourceand receiver locations. In this paper, we proposed two reverberation time estimationmethods on the basis of Schroeder’s method to eliminate the influence of the soundsource and receiver locations on the reverberation time estimation. Finally, in order tostudy the relationship between the reverberation time and the geometrical properties ofthe enclosed space, we did some acoustic test in simulation environment.