Signal extraction framework for parallelized diffuse correlation spectroscopy with SPAD arrays

Diffuse correlation spectroscopy (DCS) is an optical technique that allows for non-invasive measurements of tissue perfusion, and is often used for neuromonitoring applications. However, a major challenge of DCS is low SNR for deep tissue measurements. Recent works have demonstrated the potential for SPAD arrays to provide significant SNR increases by averaging autocorrelation signals from individual speckles; such a method is liable to bias at fast sampling rates. To fully exploit the potential of SPAD arrays, we present alternative methods to recovering the desired blood flow signal and demonstrate their effectiveness in extracting accurate fast blood flow at low-photon regimes.