An apparatus for enhancing the selectivity for spectroscopic measurements of analytes in a turbid medium is described. In one example, spatial filters are used to select only certain radii from the medium to be imaged. This selection is accomplished by placing an optical obstruction on the surface of...http://www.google.com/patents/US7742166?utm_source=gb-gplus-sharePatent US7742166 - Enhancing selectivity and/or sensitivity of spectroscopic measurements in media
