Biospeckle phenomena and their applications to blood-flow measurements

This paper reports the study on dynamic speckle phenomena observed in the light fields scattered from living objects. The laser speckles produced from living objects are called 'bio-speckles' and fluctuate temporally due to various physiological movements. Time-varying properties of bio-speckles are experimentally investigated from the analyses of spectral powers and autocorrelation functions. Based on the knowledge of dynamic bio-speckles, some methods are also introduced for evaluating the blood flows in the skin surface, gastric mucous membrane, and human retina.