Abstract: Described are a shutter assembly, a spectrometer, and a method for calibrating a spectrometer. For example, the method may include positioning a shutter including a mirror into a first position in an illumination path of an excitation light beam such that a measurement window is blocked. The mirror may be operable to direct at least one of: (1) the illumination path to a spectral calibration material, (2) a first collection path extending from the spectral calibration material, and (3) a second collection path of a spectral calibration light beam. The method may include directing a returned light from the receiving optics unit to an imaging device; processing the returned light at the imaging device into one or more image signals; analyzing and comparing the image signals with approved image signals; and providing an indication of whether the comparative results of the analysis are within acceptable tolerances.

Abstract: Innovative techniques that result in a better signal-to-noise ratio for spectrographic analysis of substances in a target than conventional techniques. In these techniques, light illuminates a target with at least some of the light penetrating the target. At least a portion of the light that penetrates the target is collected from a region on the target's surface that is not directly illuminated. Preferably, at least a majority of the collected light is light that penetrates the target. Also preferably, the light that illuminates the target is in a pattern that partially but not completely surrounds the region from which the portion of the light that penetrates the target is collected. A spectrum of at least a portion of the collected light is analyzed.

Abstract: The present invention is directed to method and apparatus for non-invasively measuring the concentration of an unknown blood analyte present in a patient. The method involves determining the concentration of a reference analyte present in the patient. Using the non-invasive optical instrument of the invention, the concentrations of the reference analyte and unknown analyte are measured. If the measured reference analyte concentration and determined reference analyte concentration are substantially the same, then the measured unknown analyte concentration is displayed. If the measured reference analyte concentration and determined reference analyte concentration are not substantially the same, then an adjustment factor is applied to the measured unknown analyte concentration and the unknown analyte concentration is displayed.