The Avisoft-CORRELATOR supports the calculation of sound similarity matrixes of spectrograms created by the Avisoft-SASLab Pro software, which allows quantifying the similarities between spectrogram images.
The selected spectrograms are compared to each other by sliding pairs of spectrograms past each other along the time axis. An optional additional sliding along the frequency axis can help tolerate slight frequency deviations. Intermediate correlation coefficients are computed for all time (and frequency) shifts. The maximum of these intermediate correlation coefficients is taken as the final correlation coefficient, which is saved in a correlation matrix.
Another application of the CORRELATOR is time and frequency aligned averaging of spectrograms.
Using the Avisoft-CORRELATOR
The Avisoft-CORRELATOR is a separate application that is installed along with the SASLab Pro software. It can be found on the Windows Start menu at Avisoft Bioacoustics > Avisoft-CORRELATOR. The executable file corr32.exe is located in the program folder C:/Program Files (x86)/Avisoft Bioacoustics/SASLab Pro.
The spectrograms to be processed must have been saved as ASCII (.txt) or Binary (.son) files using the command File > Data Export > Save Spectrogram (ASCII/Binary)... of the Avisoft-SASLab spectrogram window. All spectrograms to be correlated must be created from .wav files having the same sampling rates. The spectrogram files must all reside in the same folder.
The correlation within the Aviosft CORRELATOR software is done as follows:
- Selecting the files to be compared
- Starting the correlation process and specifying the correlation parameters
Averaging aligned spectrograms
The correlation algorithm
Discussion of the correlation method