The present invention utilizes the difference of light reception data generated based on the difference in length of substantial optical diffusion paths between a single light receiving point and a plurality of irradiation points, or between a plurality of light receiving points and a single irradiation...http://www.google.com/patents/US5057695?utm_source=gb-gplus-sharePatent US5057695 - Method of and apparatus for measuring the inside information of substance with the use of light scattering
