Abstract: A reflectometer for measuring absorption of light in selected regions of the light spectrum by a diffuse reflector. The reflectometer is adapted to precisely measure absorption resulting from the constituents present in body fluids. The sample to be measured is illuminated by a focussed light source at an angle of 45.degree. to its surface. The light diffusely reflected about the normal to the sample falls on a small round bundle of optical fibers. At the opposite end of the bundle, the fibers are arranged into a narrow rectangle. This rectangle forms the entrance slit for a concave holographic diffraction grating. The grating forms images of this entrance slit spectrally separated over a flat field suitable for recording the spectrum on film or on an array of discrete detectors.

Abstract: A reflectometer for measuring absorption of light in selected regions of the light spectrum by a diffuse reflector. The reflectometer is adapted to precisely measure absorption resulting from the constituents present in body fluids. The sample to be measured is illuminated by a focused light source at an angle of 45.degree. to its surface. The light diffusely reflected about the normal to the sample falls on a small round bundle of optical fibers at the opposite end of the bundle, the fibers are arranged into a narrow rectangle. This rectangle forms the entrance slit for a concave holographic diffraction grating. The grating forms images of this entrance slit spectrally separated over a flat field suitable for recording the spectrum on film or on an array of discrete detectors.

Abstract: An on-line detector for peach pits and peach pit fragments and the like remaining in peach halves following a pitting operation includes a sealed housing bordered on one side by an inclined view plate disposed between a feeding belt and a take-away belt. A peach half, pit cavity down, is passed by a viewing line above the view plate. Two different wavelengths of light are directed toward the viewing line and are reflected by a passing fruit section toward an array of light sensors. One of the wavelengths of light is controlled in on-off condition by a clock, being turned on during only a portion of each clock cycle. Output from each one in the array of light sensors is sampled during the portion of each clock cycle that the one wavelength is on, and differenced with the light sensor output from that sensor when the other wavelength only is on. Differencing occurs during each clock cycle and a difference output appears only in the presence of a pit or a pit fragment.