C++ Frequency-Domain Beamformer
This beamformer uses frequency-domain beamforming to find the direction of highest energy.
To perform frequency-domain beamforming, you must first transform the (time domain audio) signal to the frequency domain. In this implementation, the transformation is completed using FFTW3, an open-source FFT (fast fourier transform) library.
After the signal is placed in the frequency domain, each bin is multiplied by a complex exponential that phase shifts the bin. The cummulative result of the phase shifts is a transformation to an alternate domain: the beam-frequency domain. This domain differs from the general frequency domain as there are now frequency domain representations of the signal for every look direction, rather than every microphone input.
In designing this beamformer, great emphasis was placed on flexibility. With simple changes to main.h, this beamformer can be made to work with an arbitrary (>1) number of microphones, microphone geometry, number of beams, as well as sample rate and microphone spacing (though the beamformer does assume linear, 1 or 2-dimensional microphone spacing).
The first step to running the beamformer is to generate test data. To generate test data, run the following command:
make ang_sweep_gen
Note: you must have python3 installed on your machine, along with NumPy.
After generating test data, ensure that the frequencies listed in the include/main.h match those generated.
Next, build the project. You can do so by running the command make build in the top-level directory. You must have FFTW3 built in order to build the project.
Finally, you can run the project. This is done by running the command make run.