Abstract: Method and device to evaluate the quality of grapes, comprising a step to evaluate the presence and percentage of coloring substances in the juice by means of emitting an optical signal through the sample of juice, with the consequent monitoring of a significant calorimetric parameter, and a step to correlate the percentage of coloring substances in the sample with a defined quality and commodity class of said grapes from which the juice is obtained.

Abstract: An instrument and related process for measuring color, shade, gloss, shape and/or translucence of a tooth. First, the instrument uses searchlight illumination to illuminate a tooth with constant irradiance. Second, the instrument uses colorimetric imaging to collect time-separated frames of different wavelengths of light reflected from a tooth and to combine those frames into a color image. Third, the instrument includes a sanitary shield to establish a reference color and a predetermined distance to a target tooth. Fourth, the instrument provides line-of-sight viewing so an operator may simultaneously view a display of the image on the instrument and the object being measured. Fifth, the instrument is impervious to pollutants because it incorporates a sealed measurement window. Sixth, optical measurements of a tooth taken by a dentist are compared to optical measurements of a prosthetic restoration for that tooth to confirm satisfactory matching of optical characteristics of the tooth and restoration.

Abstract: An instrument and related process for measuring color, shade, gloss, shape and/or translucence of a tooth. First, the instrument uses searchlight illumination to illuminate a tooth with constant irradiance. Second, the instrument uses colorimetric imaging to collect time-separated frames of different wavelengths of light reflected from a tooth and to combine those frames into a color image. Third, the instrument includes a sanitary shield to establish a reference color and a predetermined distance to a target tooth. Fourth, the instrument provides line-of-sight viewing so an operator may simultaneously view a display of the image on the instrument and the object being measured. Fifth, the instrument is impervious to pollutants because it incorporates a sealed measurement window. Sixth, optical measurements of a tooth taken by a dentist are compared to optical measurements of a prosthetic restoration for that tooth to confirm satisfactory matching of optical characteristics of the tooth and restoration.

Abstract: Image data is generated by a process of radiosity, wherein a plurality of elements are defined in three dimensional space. Selected elements are set as being non-occluding and light emission values for said elements are determined by calculating the effect of light reflections between the elements. An accumulated total level of light is adjusted in response to the visibility of elements including at least one of said non-occluding elements.

Abstract: Color measuring systems and methods are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescene and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: Color/optical characteristics measuring systems and methods are disclosed. Perimeter receiver fiber optics/elements are spaced apart from a central source fiber optic/element and received light reflected from the surface of the object is measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: The indication of correct color evaluation standards of a printed matter including a paper containing a fluorescent whitening agent, is enabled even in the case where the printed matter is observed under a light source that differs from the light source used for color measurement. A spectral reflectance Pt(&lgr;) of the paper under a light source T and a spectral reflectance Pu(&lgr;) of the paper under a light source U are measured in advance and a differential component, due to the fluorescent whitening agent, is determined as Fp(&lgr;)=Pu(&lgr;)−Pt(&lgr;). For a printed matter of dot percent S, a spectral reflectance Rt(&lgr;, S) under light source T is measured, and the measured values are subject to a correction process of adding an effective component within the differential component Fp(&lgr;) that is in accordance to dot percent S to determine an estimated spectral reflectance Rtu(&lgr;, S) under light source U.

Abstract: An optical sensor system is provided which provides portions of the intensity spectrum of various types of natural and artificial light and combinations thereof. The illumination passes through a series of band pass filters or through a diffraction grating to be sensed by a plurality of photosensors sensing different portions of the spectrum. The photosensors are connected to a processing system which can determine the nature of the illuminants from characteristic areas of the intensity spectrum falling on the photosensors.

Abstract: Color/optical characteristics measuring systems and methods are disclosed. Perimeter receiver fiber optics/elements are spaced apart from a central source fiber optic/element and received light reflected from the surface of the object is measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: Color/optical characteristics measuring systems and methods are disclosed. Perimeter receiver fiber optics/elements are spaced apart from a central source fiber optic/element and received light reflected from the surface of the object is measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: Color measuring systems and methods are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: A method and apparatus for determining the condition of a test subject based on color uses a color measuring instrument to detect change in a color factor indicative of a condition such as a disease, spoilage, ageing, etc. A medical condition such as bilirubinemia that affects skin color can be detected. One measures color factors such as Hunter b and L in the subjects' skin color. For predetermined ranges of one color factor, in particular L, changes in the other color factor, e.g. Hunter b, above predetermined levels are indicative of the medical condition. In many cases, a single measurement of the color factors can be utilized as a warning of the likelihood of the medical or contaminated condition, if the ordinary range of the color factor is known for healthy individuals with skin coloration like that of the test subject.

Abstract: Methods for generating optical characteristics data of a dental object, including at least color characteristics, are disclosed. A probe is positioned in proximity to the dental object. The probe provides light to the object and receives light from the object, and the received light is coupled to a video camera, with the object positioned in the field of view of the camera. The optical characteristics data are generated based on camera data corresponding to the object and based on camera data corresponding to a color calibration standard generated with the color calibration standard in the field of view of the camera. The optical characteristics data may be stored in a record of a software database or used to prepare a second dental object.

Abstract: A colorimeter capable of calibrating color monitors, whether having cathode ray tube or liquid crystal (LCD) displays, is provided by a photometric array of photodetector and optical filter pairs. The filters include long-pass, edge filters which cover overlapping regions at the upper end of the visible spectrum and a filter which covers the entire visible spectrum. The outputs of the photodetectors are digitally synthesized to provide a response which mimics the response established by the Commission Internationale de l'Eclairage (CIE) xyz (bar) functions almost perfectly. The response which is mimicked may be represented by the CIE color matching functions. The pairs and the associated components are mounted on a printed circuit board captured in a clamshell housing and having an array of apertures which define angularly constrained fields of view of a surface from which the light, to be colormetrically analyzed, emanates.

Abstract: A method and apparatus for determining the condition of a test subject based on color uses a color measuring instrument to detect change in a color factor indicative of a condition such as a disease, spoilage, ageing, etc. A medical condition such as bilirubinemia that affects skin color can be detected. One measures color factors such as Hunter b and L in the subjects' skin color. For predetermined ranges of one color factor, in particular L, changes in the other color factor, e.g. Hunter b, above predetermined levels are indicative of the medical condition. In many cases, a single measurement of the color factors can be utilized as a warning of the likelihood of the medical or contaminated condition, if the ordinary range of the color factor is known for healthy individuals with skin coloration like that of the test subject.

Abstract: A method and apparatus for determining the condition of a test subject based on color uses a color measuring instrument to detect change in a color factor indicative of a condition such as a disease, spoilage, ageing, etc. A medical condition such as bilirubinemia that affects skin color can be detected. One measures color factors such as Hunter b and L in the subjects' skin color. For predetermined ranges of one color factor, in particular L, changes in the other color factor, e.g. Hunter b, above predetermined levels are indicative of the medical condition. In many cases, a single measurement of the color factors can be utilized as a warning of the likelihood of the medical or contaminated condition, if the ordinary range of the color factor is known for healthy individuals with skin coloration like that of the test subject.

Abstract: Detailed depth information in a three dimensional scene is recorded by a camera with a single lens system (100). In one embodiment, a lens (100) is movably attached to a camera housing (302) such that a motor (304) can move the lens (100) in the direction of the central axis of the lens (100). A two dimensional array (300) of photo-sensors is mounted in the camera along the central axis of the lens (100). As the lens system (100) is traversed along the central axis, objects at various distances (106) in front of the lens system (100) pass in and out of focus on the array (300) of photo-sensors. For a lens system (100) with a known focal length, the distance (108) between the lens system (100) and the array (300) when an object (102) comes into focus on the array (300) indicates the distance (106) between the lens system (100) and the object (102).

Abstract: A system for determining a distance to a target object or a displacement of a target object monitors electrical characteristics of a semiconductor laser aimed at the object. Light emitted from the laser is reflected from a surface of the object back into the laser. The amount of reflected light reaching the laser affects electrical characteristics of the laser. Because the amount of reflected light reaching the laser depends on the distance to the target object, the electrical characteristics of the semiconductor laser provide an indication of the distance to the target object. Also, a change in the electrical characteristics can be used to determine an amount of displacement of a target object. A system embodying the invention could also include an optical detector array which can be focused on a target object by monitoring electrical characteristics of one or more semiconductor lasers.

Abstract: Color measuring systems and methods are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: A method and apparatus for controlling the color of an article such as a paper web includes performing a comparison between target and measured reflectance values in numerous wavelength bands spanning the visible spectrum. The comparison quantifies correspondingly numerous errors that are modified by a non-linear operation, such as squaring, and then added together. The resulting sum is minimized by individually adjusting the application of a number of colorants to the article. The number of wavelength bands is greater than the number of colorants. This avoids metameric effects which are common in conventional systems that rely on three color space coordinates such as Hunter Laboratories L, a, b; C.I.E. L*, a*, b*; chromaticity x, y, z; and tristimulus X, Y, Z. Colorant response simulators enable the effects of changes in application of colorants to be tested while the actual application of colorants to the article is unchanged.

Abstract: The present invention provides a generally applicable apparatus and method for achieving measurements of a constituent in a sample. This is achieved by employing a detection means having a plurality of detectors responsive to radiation in a selected region of the spectrum, e.g., the infrared. In most embodiments, at least two of the detectors provide broad wavelength bandpass. If narrow bandpass sources or detectors are used, the information generated is processed in a manner similar to broadband information. The broad bandpass response of the detectors can be contrasted with the approach of classical spectrophotometry, in which the spectral response of the detectors is designed to be as narrow as feasible, and substantially narrower than the spectral features of the constituent or constituents of interest. The data is processed such that the contributions of known background constituents and scattering is eliminated prior to further processing, thereby yielding a better result in high background situations.

Abstract: A method for determining the appearance of an object to be replicated and an apparatus therefor are described herein. The method consists in providing a controlled illumination to illuminate a surface of the object, measuring the object with a CCD camera to collect an image map of a plurality of points on the surface and processing that information to produce an appearance mapping of the object. Calibration of the apparatus is done by measuring calibration patches illuminated with the same illumination. When the apparatus is made in view of replicating the appearance of an object, a comparison can be done by similarly producing an appearance mapping of the replicate and by comparing it to the appearance mapping of the object.

Abstract: A color measuring apparatus is provided with a radial illumination unit for projecting illumination light to a measurement object at a first illumination angle in a plurality of directions, a unidirectional illumination unit for projecting illumination light to the measurement object at a second illumination angle in a single direction, a unidirectional light receiving unit for receiving a light ray reflected at a first angle .theta.1 from the direction of regular reflection out of illumination light projected from the radial illumination unit and reflected by the measurement object, and a light ray reflected at a second angle .theta.2 from the direction of regular reflection out of illumination light projected from the unidirectional illumination unit and reflected by the measurement object, the second angle .theta.2 being larger than the first angle .theta.1, and a processing unit for calculating a color value at the first angle .theta.1 and a color value at the second angle .theta.

Abstract: A colorimeter for measuring colour of process medium comprising two light sources and two detectors both light sources being arranged to emit a beam through the process medium and the windows adjoining the process medium to both detectors. In order to achieve a solution functioning reliably the windows adjoining the process medium at both light sources are formed from a triangular prism, the two surfaces of which being at an angle to each other, are arranged to divide the beam arriving from the light source into two beams travelling in different directions so that both beams proceed to the process medium through the same part of the window surface formed by a third surface of the prism. Mirror surfaces arranged to gather radiation arriving form both light sources to a sensor of the detector are formed at both detectors.

Abstract: This invention relates to a method for matching a color formulation to a color shade model in the field of a color- and/or effect-imparting surface coating. The reflecting surface of a color shade, which is to be rematched, of a colored surface coating is determined metrologically over the visible spectral region using a goniometric spectral photometer with variation of the angle of measurement. The associated standard tristimulus values and/or the vectors in the CIELAB color solid which are derived therefrom are calculated from the measured reflection factors or spectral energy factors. Those formulations and/or color shades which exhibit reflection properties or properties derived therefrom which are the most similar to the measured color shade model are subsequently identified from a formulation database by means of the reflection spectra or the calorimetric dimensional numbers derived therefrom.

Abstract: A light source used to measure color involves associating a light emitter that emits light having a first spectral distribution with a wavelength-shifting medium that absorbs the emitted light and re-emits the light at a second spectral distribution that approximates one of the three color curves of the CIE standard X, Y, and Z tristimulus functions. Preferably, the light source involves associating known blue light sources with a green-converting lens and a red-converting lens where materials integrated into the lenses, preferably fluorescent organic dyes, absorb the blue light and re-emit green and red light respectively. The blue light, the converted green light, and the converted red light, are generated to closely match the CIE standard X, Y, and Z tristimulus functions in order to measure color in a manner that correlates to the color sensitivity of the human eye.

Abstract: Color space models are developed using designed experiments of pigment and binder ratios of a plurality known paint formulations for correlating color coordinates in a three-dimensional color space and paint constituents. Capabilities of the paints are determined by limits placed upon the constituents. Each color space model is used to return respective constituent apportionments for achieving predetermined color coordinates. Constituent apportionments within the respective limits correspond to paint formulations within the color space capability of the corresponding known paint formulation. When all such respective constituent apportionments are within the respective limits for each known paint formulation, the predetermined color coordinates are achievable and within a common color space capability of the known paint formulations.

Abstract: A template-type calorimeter comprising a light-transparent substrate having a diffraction grating on a surface thereof, the diffraction grating being operative to diffract light incident thereon from a spaced-apart aperture into its constituent spectral components. A template is provided on a surface of the substrate and arranged to receive the diffracted spectral components. The template has formed thereon at least three spatial filters, each for selectively transmitting diffracted spectral components in accordance with respective ones of the desired color-matching functions such as the CIE x(.lambda.), y(.lambda.), z(.lambda.) or r(.lambda.), g(.lambda.), b(.lambda.) color-matching functions. The diffraction grating and the template may be mounted on opposite sides of the substrate, or they may be mounted in a laterally spaced-apart relationship on the same side of the substrate, in which case the opposite side of the substrate is coated with a reflective material.

Abstract: A colorimeter method and apparatus is described that is used to accurately deduce the color of a source which is varying in intensity with respect to time. The colorimeter consists of a plurality of sensors with varied spectral responsivity, a means of shielding these sensors from the effects of ambient illumination and a computational element to analyze the temporal and intensity variation of the signal under measurement. The output from the sensors is integrated and analyzed based upon the measured light intensity, time variant, and characteristics of the source. Sources such as CRT monitors, Flat Panel displays, and stroboscopic illuminators, are typical representations of time variant sources.

Abstract: Color measuring systems and methods such as for determining the color or other characteristics of teeth are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed.

Abstract: Color measuring systems and methods such as for determining the color or other characteristics of teeth are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed.

Abstract: When a required color image is to be output from a color image output device using an image input device for outputting color separation value signals corresponding to a read color image, if a change in image reproduction environment is detected by each of sensors provided to these devices, learning processing is properly executed. Using neural networks of a color conversion section and a color correction section which are optimized by the learning processing, a signal output from the image input device is color-converted and color-corrected. The color-corrected image signal (color separation value signals) is supplied to the color image output device to reproduce a color image.

Abstract: Improvement methods and apparatus for determination of optical properties of objects have been developed. The apparatus and methods of the invention provide an analog of color perception of human vision, preferably in the near infrared region, replacing spectrophotometers and narrow band sources used in other non-invasive near infrared detection methods. A plurality of detector units are used, each covering a broad and overlapping region of the detected spectrum, paralleling color perception and colorimetry. The improvements are primarily concerned with improving the signal-to-background (or noise) ratio such that the data stream is improved. These improvements use congruent sampling, comparison of different data streams from different sample portions or filter sets, using an interrogation system with sufficient speed to allow testing of arterial blood, and using a filter with a spectral structure. In some circumstances, a neural net is used for analysis, allowing the system to learn.

Abstract: The present invention provides a generally applicable apparatus and method for achieving measurements of a constituent in a sample. This is achieved by employing a detection means having a plurality of detectors responsive to radiation in a selected region of the spectrum, e.g., the infrared. In most embodiments, at least two of the detectors provide broad wavelength bandpass. If narrow bandpass sources or detectors are used, the information generated is processed in a manner similar to broadband information. The broad bandpass response of the detectors can be contrasted with the approach of classical spectrophotometry, in which the spectral response of the detectors is designed to be as narrow as feasible, and substantially narrower than the spectral features of the constituent or constituents of interest. The data is processed such that the contributions of known background constituents and scattering is eliminated prior to further processing, thereby yielding a better result in high background situations.

Abstract: The apparatus for determining the color stimulus specification of translucent objects comprises two light sources to create on the surface of an object under test two light spots which have different size. The light is transmitted from the light sources to the object under test by means of an optically conducting fiber bundle. The light reflected by the object under test is received by a lens and led via an optically conducting fiber bundle to a spectrometer. Thereafter, the measurement signal is digitized and arithmetically evaluated in a microprocessor. Due to the fact that two differently sized light spots are used, the measurement error which results in determining the color specification value of a translucent object can be defined and corrected. For this purpose, use is made of reference measurement values which have been obtained by measuring opaque reference objects and which have been stored in a memory module of the apparatus.

Abstract: The present invention provides a method and apparatus for accurately matching colors. The color matching system includes a host computer and a color input device in communication with the host computer. Preferably the color input device is capable of obtaining spectral data, such as that obtained using a spectrophotometer. The host computer includes a color library, a color management system, a monitor, and a user interface. In one aspect of the invention, the user selects a target color, a color library to use for matching, a color distance tolerance, and a light source under which the colors are to be matched. The target color is compared to the colors in the library and the color or colors in the library that are within the specified color tolerance are reported. In a second aspect of the invention, the user selects a color and two illuminants. The color under each of the two illuminants is compared and the color distance between the two is reported.

Abstract: A three dimensional sensor includes an illumination source that produces broadband, high intensity optical energy. This optical energy includes a number of individual wavelength components. The individual wavelength components are impinged in a spot on a target. Dispersion is applied to the light reflected from the spot, either before target impingement, after target impingement, or both, whereby light of different colors is focused at different distances from the target. A maximum reflected wavelength, dependent on target range, is detected to determine the target range. In one embodiment, temporal modulation is applied to the light before target impingement. A stationary detector determines the target range by relating the maximum light received to the time it is received in order to determine the color received at that time. In another embodiment, all colors are reflected from the target simultaneously, and the reflected beam is chromatically dispersed in the transverse direction.

Abstract: Color measuring systems and methods such as for determining the color or other characteristics of teeth are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed.

Abstract: Color scanner apparatus utilizing color separation with multiple point narrow band illumination from N-colors of LEDs may comprise a multicolor light source for successively illuminating an object with N different colors of light between about a color red and a color blue. A photosensor responsive to light reflected from the object converts the reflected light into sets of color image data signals corresponding to each of the N different colors. A color image data processing apparatus connected to the photosensor converts the sets of color image data signals corresponding to each of the N different colors into equivalent tristimulus values.

Abstract: A stimulus values direct reading colorimetric instrument comprising a plurality of photoelectric sensors having different spectral responsivities equal or approximately equal to color matching functions X(.lambda.), Y(.lambda.), and Z(.lambda.); and measuring and display device to measure and display the tri-stimulus values X,Y and Z and the chromaticity of the light to be measured by computing the photoelectric sensor output signals caused by the light, wherein the instrument calculates the stimulus values corresponding to the tri-stimulus values and measures the chomaticity by providing at least one corrective photoelectric sensors so as to maximize their spectral responsivities in the vicinity of the transmission threshold wavelengths of each sensor and taking the sum of the output signals from the sensors and the corrective sensor after multiplying each coefficient assigned to the signals by each output signal, respectively.

Abstract: A spectrophotometer apparatus (200) is adapted to provide spectral reflectance measurements of object samples. The apparatus (200) comprises a source light (254) and a reflection optics assembly (264, 268). Signals representative of reflected light are analyzed and data provided to an operator representative of the spectral response characteristics of the object sample (252). The apparatus (200) further comprises a side sensor (276) having a fixed spectral response characteristic for compensating the reflectance measurements in accordance with the light intensity emanating from the lamp. For purposes of calibration, a series of time-sequenced measurements are made of a reference sample. Utilizing these measurements, the apparatus (200) provides computations of compensation coefficients for each spectral segment.

Abstract: The present invention relates to a dental device which detects the color of a damaged tooth and automatically determines the proper restorative dental material to be used to repair the damaged tooth. The device illuminates the tooth with light and detects the various color components of light reflected off the tooth. Signals indicative of the various color components are then processed and compared against known reference signal values indicative of the color of various restorative materials in order to determine which of the plurality of restorative dental materials best matches the color of the tooth. The device then displays a message indicative of the chosen material. The detector is preferably a lightweight, hand-held, battery powered device, which includes a wand assembly which is placed against the tooth. A disposable, replaceable, protective sheath is placed over the wand to ensure the health and safety of the patient.

Abstract: The present invention provides a method and apparatus for accurately matching colors. The color matching system includes a host computer and a color input device in communication with the host computer. Preferably the color input device is capable of obtaining spectral data, such as that obtained using a spectrophotometer. The host computer includes a color library, a color management system, a monitor, and a user interface. In one aspect of the invention, the user selects a target color, a color library to use for matching, a color distance tolerance, and a light source under which the colors are to be matched. The target color is compared to the colors in the library and the color or colors in the library that are within the specified color tolerance are reported. In a second aspect of the invention, the user selects a color and two illuminants. The color under each of the two illuminants is compared and the color distance between the two is reported.

Abstract: A method and apparatus for determining the condition of a test subject based on color uses a color measuring instrument to detect change in a color factor indicative of a condition such as a disease, spoilage, ageing, etc. A medical condition such as hyperbilirubinemia that affects skin color can be detected. One measures color factors such as Hunter b and L in the subjects' skin color. For predetermined ranges of one color factor, in particular L, changes in the other color factor, e.g. Hunter b, above predetermined levels are indicative of the medical condition. In many cases, a single measurement of the color factors can be utilized as a warning of the likelihood of the medical or contaminated condition, if the ordinary range of the color factor is known for healthy individuals with skin coloration like that of the test subject.

Abstract: A plurality of principal-component spectral distributions are determined in advance by analyzing spectral distributions of a multiplicity of sample films; light transmitted through a film to be estimated is measured by spectrally diffracting the transmitted light into wavelengths of different bands or into different wavelength bands the number of the wavelengths or wavelength bands being equivalent to that of the plurality of principal-component spectral distributions; coefficients for expressing the spectral distribution of the film to be estimated as a linear sum of the plurality of principal-component spectral distributions are determined on the basis of photometric values of the respective wavelengths wavelength bands and the plurality of, principal-component spectral distributions; and the spectral distribution of the film to be estimated is estimated by determining the linear sum of the plurality of principal-component spectral distributions by using the coefficients obtained.

Abstract: A device for determining the color value of light includes a linear graded interference filter, which has only one expansion direction through which the light is incident on a number of photodetectors. The photodetectors are arranged adjacent to one another in the expansion direction of the graded interference filter and are used to supply measuring signals, on the basis of which the color value is calculated. Focusing optics arranged in front of the graded interference filter are used to focus the light onto the photodetectors. The light is fed via a plurality of optical guides, whose light exit ends are arranged closely adjacent to one another along one or more rows extending in the expansion direction of the graded interference filter. The focusing optics contain a cylindrical lens extending in the expansion direction. Advantageously, the photodetectors are PIN photodiodes and the optical waveguides are optical fibers.

Abstract: Light reflected from a sample coating is measured in three directions that are angularly spaced by angles of about 15.degree., about 45.degree., and about 75.degree. or about 110.degree. from the direction of regular reflection of illuminating light toward the direction in which the illuminating light is applied. Color differences are then determined from the measured lights and known values of reference color tones, and one of the reference color tones whose color difference is minimum is determined. Flop values of the sample coating with respect to lightness, saturation, and hue are determined from the measured lights, and the color tone of the sample coating is determined based on color differences between the determined flop values and flop values that are characteristics of the reference color tones.

Abstract: A photographic color temperature meter capable of measuring light including stationary light and flash light. The meter controls timing of light measurements so that light measurement is performed during the time when stationary light and flash light are included and when only stationary light is included. Thereafter, calculation of color temperature only of flash light is performed.

Abstract: Apparatus for obtaining a desired tint, which apparatus uses a light source to provide a gamut of colours. The apparatus comprises wheel and paddle (34,60) which enable a tint to be obtained from such light in such a manner that the hue and saturation of the tint can be varied substantially independently of one another, whilst maintaining a given brightness. The invention extends to a method using such apparatus, and to equipment comprising a set of coloured filters, and also to a method in which a tint created by a combination of filters selected from a set of filters is varied, by removal, addition, or replacement of one or more filters of the combination, to match the selected tint, and finally to the making of lenses using such methods, and the lenses themselves.

Abstract: A device for measuring the color of a sample is provided comprising: a camera for transforming received light into electrical signals providing color information, the camera being positioned with respect to the sample to receive at least a portion of any light reflected by the sample; and a signal processor, coupled to the camera, for processing electrical signals produced by the camera to obtain the color information about the sample embedded in the signals.