An exemplary non-invasive measurement system includes a single-photon counting camera and a processor. The single-photon counting camera includes an array of SPAD detectors configured to detect, during a sequence of gated time intervals, coherent continuous light that exits a body after the light enters and scatters within the body, and output a plurality of electronic signals representative of the detected light. The processor is configured to generate, based on the electronic signals, a sequence of speckle pattern image frames corresponding to the gated time intervals. Other exemplary non-invasive measurement systems are also described.
