Abstract: An improved optical system is disclosed for rapid, accurate spectral analysis of the reflectivity or transmissivity of samples. A concave holographic diffraction grating oscillated at high speed is utilized to provide a rapid scanning of monochromatic light through a spectrum of wavelengths. The grating is positively driven at very high speed by a unique cam drive structure comprising identically shaped conjugate cams. The rapid scan by the grating enables the reduction of noise error by averaging over a large number of cycles. It also reduces the measurement time and thus prevents sample heating by excessive exposure to light energy. A filter wheel having dark segments for drift correction is rotated in the optical path and is synchronous with the grating. Source optics is employed to optimally shape the light source for particular applications.

Abstract: An improved optical system is disclosed for rapid, accurate spectral analysis of the reflectivity or transmissivity of samples. A concave holographic diffraction grating oscillated at high speed is utilized to provide a rapid scanning of monochromatic light through a spectrum of wavelengths. The grating is positively driven at very high speed. The rapid scan by the grating enables the reduction of noise error by averaging over a large number of cycles. It also reduces the measurement time and thus prevents sample heating by excessive exposure to light energy. A filter wheel having opaque segments is rotated in the optical path and is synchronous with the grating. The filter wheel is divided into two arcuate segments separated by the opaque segments arranged approximately 180 degrees apart. One arcuate segment of the wheel transmits only first order light. The other arcuate segment transmits only second order light.

Abstract: An improved grain quality analyzer, for analyzing the percentage concentration of various constituents, e.g. protein and water, in a grain sample, photo-optically measures the change in the optical density of the sample, .DELTA. OD, in a range of characteristic wavelengths and, for protein, in a range of neutral wavelengths and uses these measured values to compute the percentage concentration of the constituents.A grain sample is irradiated with light, the wavelength of which sweeps across the infrared light-spectrum including a range of wavelengths termed characteristic wavelengths, and, for protein, a range of wavelengths termed neutral wavelengths.

Abstract: A cam filter wheel apparatus is disclosed for tilting interference filters in order to achieve variation in the light wavelength transmitted by each filter. The wheel apparatus contains a number of filters each mounted so as to pivot and change its inclination with respect to an incident light beam as the filter wheel rotates each filter through the light path. The pivot motion is achieved by a cam follower associated with each filter which rides on a stationary cam track.

Abstract: In a sample used to test the accuracy of an instrument designed to quantitatively analyze organic material from the optical characteristics of the material, a sealed container is filled with a mixture of ground quartz and the organic material to be analyzed in the instrument. A window is provided in the sealed container to permit irradiation of the mixture so that the instrument can perform a quantitative analysis on the mixture in the sealed container.

Abstract: In an optical analysis system, six interference filters are mounted on a wheel on a cylindrical locus. The wheel rotates to move the filters in sequence through a beam of light and to vary the angle of incidence of the light to the filters as the filters move through the beam of light so that the wavelength passed by the filters is swept through a range of values. The intensity of light reflected from or transmitted through a test sample is detected to provide an indication of the reflective or transmissive optical density of the test sample at specific wavelengths. The angular position of each of the filters on the wheel is adjustable to make the range of light wavelengths transmitted by each filter adjustable.

Abstract: An automatic test instrument for gaging the percentage of various constituents in organic substances by comparing the reflective optical density of the subject at various wavelengths. Narrow band optical filters are connected together in the form of a rotatable paddle wheel positioned so that the filters can be individually swept through the incident light path between the specimen and wideband light source. As the filter wheel turns, the band of light passed by each filter is progressively shifted with the changing angle of the filter relative to the light path. The filter wheel configuration includes opaque vanes extending from the ends of the filters to periodically interrupt the passage of light to the specimen. Photocells are positioned to sense the level of light reflected from the specimen. The output of the photocells is sampled at pedetermined times relative to the rotation of the filter wheel to yield values indicative of reflected intensity at certain wavelengths.

Abstract: An automatic test instrument for gaging the percentage of various constituents in organic substances by comparing the reflective optical density of the subject at various wavelengths. Narrow band optical filters are connected together in the form of a rotatable paddle wheel positioned so that the filters can be individually swept through the incident light path between the specimen and wideband light source. As the filter wheel turns, the band of light passed by each filter is progressively shifted with the changing angle of the filter relative to the light path. The filter wheel configuration includes opaque vanes extending from the ends of the filters to periodically interrupt the passage of light to the specimen. Photocells are positioned to sense the level of light reflected from the specimen. The output of the photocells is sampled at predetermined times relative to the rotation of the filter wheel to yield values indicative of reflected intensity at certain wavelengths.

Abstract: A technique for automatic detection of abnormalities, particularly pathology, in biomedical specimens. Light transmittance or reflectance data over a large number of wavelengths for numerous samples are correlated mathematically with conventional clinical results to select test wavelengths and constants for a correlation equation. Optical instrumentation with an analog or digital computer applies the resulting correlation equation to the spectral data on a given specimen at the test wavelengths to determine quantitatively the presence of the abnormality.

Abstract: A colorimeter includes an objective for focusing an object image on a first half of a viewing screen. A standard light reference beam is projected onto the second half of the screen. A moving shutter alternately blocks the first half then the second half of the screen. A light detector is responsive to the alternating images on the screen as they pass through color filters. The detector output may provide information of spectral distribution or color deviation of the object, relative to the standard reference.FIELD OF THE INVENTIONThe invention generally relates to colorimeters, and more particularly to a colorimeter for measuring color and spectrum distribution, based on the formation of an optical image of an object prior to measurement.BRIEF DESCRIPTION OF THE PRIOR ARTThe "narrow" definition of color flows from the rules set down by the C. I. E. (International Commission for Illumination) for the measurement of color on flat, uniform, opaque surfaces.