This week, I debugged and tested the delay-and-sum beamforming algorithm with the goal of either getting delay-and-sum beamforming to successfully separate speech in our recordings, or showing that delay-and-sum beamforming with our current mic array would not be sufficient to separate speech and that we should use a different approach.
In order to test the delay-and-sum beamforming algorithm, I first generated a sine wave audio in matlab. I played this sound through an earbud towards the mic at angle 0 on the mic array (mic 1).
I played the sine wave while recording from the mic array. Then, I passed the mic array recordings through my delay-and-sum beamforming code. Though there was a lot of background noise, I found that beamforming towards the source (the earbud) gave an output with a greater SNR (judged by ear, not computationally) than beamforming away from the source. Below are the audio outputs for beamforming towards the source – look direction = 0 – and beamforming directly away from the source – look direction = pi.
look direction = 0:
look direction = pi:
On Thursday, Charlie and I met with Dr. Stern to discuss alternative approaches to speech separation, particularly Phase Difference CHannel Weighting (PDCW) which Dr. Stern published. I got the beamforming test results (shared above) before this meeting, so we went in the goal of finding new algorithms to try rather than trying to get delay-and-sum beamforming working.
We are a bit behind schedule since we have decided to abandon delay-and-sum beamforming in favor of a non-beamforming speech separation approach. To catch up this week, we will collect recordings that we can pass into the PDCW algorithm and determine how well this algorithm can separate speech with our mic setup.
This week, Charlie and I will collect recordings that fit the assumptions of the PDCW algorithm and test the algorithm on them. From there, we will see what we can get working with the PDCW algorithm and we will meet up again with Dr. Stern to discuss our results and get some more guidance (as he suggested in our last meeting).