Developing an open source method to determine blood velocity from the audio output of a commercial ultrasound Doppler

Ultrasound machines can be used to find the blood flow velocity of a subject. The raw audio output from the machines is interpreted as the doppler-shifted signal due to the blood flow. The data can be be used to determine the Doppler-shift and used to determine blood flow velocity as a function of time. A fast Fourier transform (FFT) algorithm on the audio output provides mean frequency. By applying the FFT to small windows of data, the output velocities from each window are found are plotted against time to create a visual model of how the blood velocity changes over time. The blood velocity will then be correlated with other physiological measurements.