Global reset-speckle contrast optical spectroscopy.

We introduce and validate a novel variant of speckle contrast optical spectroscopy that leverages the global reset shutter function of a camera and lookup table-based noise corrections. This new approach enables recovery of speckle contrast at multiple exposure times from a single frame acquisition. It also facilitates noise suppression required for operation at the shorter, more sensitive exposure times. We demonstrate the resulting improved noise corrections and increased information content in benchtop and in vivo experiments, which facilitate robust estimation of both the absolute flow index and the often-overlooked coherence coefficient, β.