Comparison of synthetic exposure and sequential exposure for multiple exposure speckle imaging of blood flow

We have compared multiple exposure speckle imaging using two approaches: (i) duration modulation of laser diode pulses with fixed exposure time and (ii) synthetic exposure created from the sum of frames obtained at 1ms exposure time. Both methods have been applied to evaluate controlled flows in micro-channels. The results demonstrate that the synthetic exposure method provides accurate speckle contrast data over a wide range of exposures, channel diameters and flows.