Abstract: The height of a surface (25) along an axis (4) is determined by measuring the axial position of an irradiated spot (31) formed on the surface at the intersection of the surface and the axis. Radiation reflected by the surface and collected by a lens (8) forms an image spot (32) on the axis (4). The position of the image spot is determined by measuring the intensity of the radiation at at least three positions along the axis by means of a detection unit (35). The output signals (44, 44') of the detection unit are processed in an electronic means (43) for determining the position of the highest radiation intensity and for supplying a signal (43') whose magnitude represents the axial position of the image spot (32), hence, of the irradiated spot (31 ).

Abstract: A method of and apparatus for determining if a given data point having three parameters falls within a population defined by more than four known data points, each data point having the three parameters, the method and apparatus involving determining if the given data point falls within any of a plurality of tetrahedrons, each of the tetrahedrons having four vertices, each of the vertices of each tetrahedron being defined by one of the known data points.

Abstract: A three-dimensional object is modelled by solidifying superposed layers in such a manner that on an already solidified layer a following layer of initially liquid or powdery material is solidified by light action or the like in correspondence with the form of the object.

Abstract: A pattern extracting apparatus extracts a pattern of a desired color from an object containing a plurality of color patterns. In the apparatus, the object is irradiated by light to provide data relating to color components and the data relating to color components are converted into Munsell color data H (Hue), V (Value) and C (Chroma). After that, a pattern of a specific color is extracted from the object based on the Munsell color data.

Abstract: Improvements in non-invasive detection methods for glucose and other constituents of interest in a sample 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: A two-dimensional colorimeter focuses light through a beam splitter onto a rotary filter so that a first light receiving element can receive light from multiple points on a sample. A rotating filter can provide multiple measurements based upon different wavelengths of light. A portion of the light from the beam splitter also contacts a spectral sensor which separates the light from a particular point into primary wavelength elements which are converted into electrical signals. Based upon these primary wavelength elements, the first signals from the light receiving element are corrected. As a result, the measurement of chromaticity of multiple points on a sample can be performed accurately using a device of simple construction.

Abstract: A method and apparatus for determining the color of an object which is transparent, diffusing, and absorbent, by illuminating an area of the object by means of a diffuse light flux that is substantially uniform and isotropic, by picking up the light backscattered by a small fraction of the illuminated area of the object by means of an optical system that comprises achromatic doublets and both infrared and ultraviolet filters, together with a diaphragm, and spectrally analyzing said light by means of interference filters and photodetectors. The invention is particularly suitable for determining the color of teeth in the mouth.

Abstract: A new non-invasive non-spectrophotometric method for measuring the blood concentration of analytes such as glucose has been developed. The apparatus and methods of the invention exploit analogies with colorimetry and color perception to extract concentration measurements from the global structure of the intensity versus wavelength absorbance or transmission profile. A plurality of broad spectrum filters transmit distinguishably coded beams of radiation in overlapping portions of the spectrum to the sample. Radiation reflected or transmitted by the sample is detected and decoded. LED's may be used instead of the broad spectrum radiation generating device and the filters. Further, a scanning interferometer can be used as the illuminating and coding device. In a preferred mode, congruent illumination is utilized. The coded signals are analyzed by analogy to colorimetry and visual processing and can be converted into concentration measurements.

Abstract: The invention relates to a method and to apparatus for determining the color of a translucent object such as a tooth by measuring the reflectance of said object at wavelengths corresponding essentially to sensitivity maxima of the human eye to hue and to saturation, by calculating the luminance of white included in the luminance of the object illuminated by a determined standard illuminant, by calculating a saturation percentage for the color of the object as seen by the human eye, and by determining the pigmentations of said color relative to white.

Abstract: To enable top illumination densitometers to be used for measuring light reflections on colored control fields of so-called printing control strips, it is necessary to center the measuring openings of such instruments accurately on the control field so as to focus properly. For this purpose, there is provided a hand-held instrument which comprises an instrument housing and a measuring head in the housing, the measuring head having an outer wall, defining a measuring aperture facing the measuring plane and containing a source of measuring light and a measuring light receiver arranged to receive light from the source through light guiding channels.

Abstract: A process for shading paint to match the color of a standard color paint which process involves the use of transparent film to optically simulate the effect of reading color through the conventional clearcoat layer, which eliminates the steps of cooling, spraying, flashing and baking the clearcoat with each iteration of test panels, with resultant significant decrease in process time.

Abstract: A portable colorimeter housing has an upper portion which is mounted on a lower portion in a cantilever fashion and is adapted to receive sheets larger than the device for purposes of obtaining tri-stimulus color measurements. An adjustable paper guide determines the distance that a sheet is inserted between upper and lower plates. A sheet to be measured inserted in the opening will operate a micro switch which activates a motor operative to advance the sheet between a motor-driven drive wheel in the lower plate and an idler roller in the upper plate. Transmittance or reflectance measurements are taken by means of photodetector cells including colorimetric filters. A user programmable processor performs pattern recognition and control functions.

Abstract: A tristimulus colorimeter for color displays is required to remove measurement errors caused by deviations of the spectral responsivities thereof from the color matching functions. The colorimeter is provided with a light receiving unit having spectral responsivities close to the color matching functions, a tristimulus values operation unit for performing operations to calculate tristimulus values, and a chromaticity operation unit for performing operations to calculate a chromaticity. The colorimeter is further provided with a spectral distribution storage unit for storing spectral distributions of representative colored lights, a mixing ratio operation unit for performing operations to calculate a mixing ratio of a mixed light including colored lights of red, green, and blue. The colorimeter is also provided with a spectral distribution operation unit and a corrected chromaticity operation unit.

Abstract: A new non-invasive detection method for glucose and other constituents of interest in a sample has 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 noninvasive 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. In some circumstances, a neural net is used for analysis, allowing the system to learn. A novel method for background discrimination is also described.

Abstract: Skin coloration categories are identified based upon blue and yellow undertones of the skin using a color measuring device, developing the Hunter b value, utilizing that value alone to determine which of several categories of skin coloration a subject's skin exhibits. Category selection is made by comparison of measured Hunter b with ranges of Hunter b value of skin color categories. Instrumentation to effect the method includes the color measuring device, a central processing unit (CPU), memory storing the ranges of Hunter b, and an output device such as a printer, LCD, or CRT. The skin color Hunter b is calculated and compared to stored ranges to assign a category. The output device displays the category of skin color based upon the central processing unit's comparison. Colors compatible with skin color categories are identified or formulated based upon broad color family designation, yellow, brown, red, etc.

Abstract: Apparatus for monitoring, converting and calibrating the spectra displayed by a colored object, using wavelength dispersion provided by a variable wavelength filter. The apparatus may serve as a spectrophotometer, as a colorimeter, or as a spectroradiometer or other device that monitors and calibrates a light signal by decomposition of the signal into a wavelength distribution. The apparatus may also be used as part of a feedback network to monitor and correct colors displayed by a color monitor, color printer, color scanner or other similar peripheral device controlled by a computer that is part of the network.

Abstract: A method of characterization of a coating on a surface such as a paint coating having metallic flakes distributed within such coating. Single and multi-angle models are utilized. The coating is characterized by measurements having components of light reflected by the metal flakes and attenuated on its exit route from the coating, of light scattered in the entering path of the beam as it travels through the coating, of light scattered by the reflected beam on its exit from the coating, of light scattered in the entering path then reflected by the metallic flakes and attenuated in the coating on exiting, and of light scattering in the exit path, both to the metallic flake and reflected by the flake and attenuated on its exit from the coating. Methods of color matching a coating having a metallic flake distribution within the coating are included using reflectance factors and tristimulus values and minimizing the sum of the squares of the deviation between samples.

Abstract: A microcomputer controlled manual densitometer for the analysis of print control fields has a manual and an automatic operating mode. In the manual mode the measuring functions desired are selected by the operator, while in the automatic mode the measuring function is selected automatically on the basis of the type of the print control field measured. The densitometer is able to recognize the color of the print control field including overprint situations, and to distinguish between solid-tone fields including overprint situations, and to distinguish between full-tone fields and half-tone fields with two different nominal dot areas. For solid-tone fields the color and the solid-tone density, for overprint fields the ink trap and the overprint color and for half-tone fields the dot gain, the color and the nominal dot area, are detected and displayed. The color recognition is based on the relative variables of grayness and color hue error.

Abstract: A measuring apparatus includes a flash tube for emitting flash light to a target in a first short period and a second short period, a detector for detecting amounts of light from the target in the flash light of the first short period and the flash light of the second short period, a receiver for receiving the flash light irrespective of the target to detect each reference light amount, an evaluator for evaluating the flash light according to the reference light amounts to generate a compensation signal for a characteristic of the flash light with respect to a characteristic of an ideal light source, and a calculator for calculating a characteristic value of the target under ideal light source according to the target light amount and the compensation signal.

Abstract: Apparatus for color measurements according to the C.I.E. system comprises a first fiber optic cable for receiving and linearizing light from a light source, a lens system for spectrally displaying the linearized light and focusing the light on one end of a trifurcated fiber optic assembly that integrates and separates the light according to the three C.I.E. tristimulus functions. The separated light is received by three photodiodes and electronically evaluated to determine the magnitude of the light corresponding to the tristimulus functions.

Abstract: A method giving a color tone-evaluating result which catches the deepness and transparency feelings of a coating film in an objective manner, and a device for use of this method. The evaluating results are obtained by projecting a luminous flux on a coating film, the high light saturation and/or high light excitation purity of the coating film are gotten on a basis of a high light part which is in an angle range of 5.degree. to 15.degree. against the regularly reflecting luminous flux in the reflecting light, and that, if necessary, the shade saturation and/or shade excitation purity are gotten on a basis of a shade part which is in an angle range exceeding 15.degree..

Abstract: An improved optical filter for use in an optical measurement instrument has a corrective optical glass filter with a negative deviation in the range of 470 nm added to the optical filter to offset a positive deviation in the range of 470 nm in an amber or blue glass filter used in the optical filter. The improved optical filter in interposed between a photoelectric element in the optical measurement instrument and the source of electromagnetic radiation. The photoelectric device converts the electromagnetic radiation to an electrical signal which is processed and displayed. In one embodiment of the invention the optical filter has a spectral response matching that of the average human eye and in a further embodiment the optical filter has an approximate equal response over a spectral range from ultraviolet to infrared.

Abstract: A device for separating a beam of white light (14,56 ) into a plurality of elementary beams of particular color, integrated in a chromatic analyzer for the printing of color photographs, comprisingan optical sensor (15-17)a plurality of photosensitive sensors (24-26), each sensor making it possible:to collect the light (28,30,31) reflected by an optical system (21-23),then to convert the light signal so received into an electrical signal,and finally to amplify it (35-37);a unit (38,39) for processing the amplified electrical signals,wherein the optical system consists of a plurality of dichroic filters (21-23) of complementary color which are parallel and which are inclined relative to the optical axis (B) of the emerging beam (18), each filter making it possible to reflect the quantity of light corresponding to the color of this filter and to transmit the light in the other colors.The invention is used on installations for the printing of photographic proofs.

Abstract: A color recognition system which illuminates a test surface through the use of a source light and fiber optic cables. The light transmitted to the test surface is reflected into a light pipe and then transmitted through fiber optic cables to a first plurality of color filtered photo detectors. The photo detectors produce quantitative color component values for the tested surface. Light is also transmitted directly from the source light through fiber optic cables to a second plurality of color filtered photo detectors. The second plurality of photo detectors produce quantitative color component values for the light source. The values produced from the first plurality of photo detectors are then adjusted with respect to the values produced from the second plurality of photo detectors.

Abstract: The stack reflectance is predicted from an on-line, wavelength dependent measurement of the sheet reflectance and the on-line measurement of the sheet opacity at a wavelength interval. The stack reflectance Rst is then used to predict and/or control stack color, preferably by using the parameter K/S=(1-Rst.sup.2)/2 Rst where K is the dye absorption coefficient and S is the dye scattering coefficient.

Abstract: An optical thickness measuring apparatus comprises a light source, a spectral device which separates light produced by the light source into its spectral components, and a photodetector for detecting the light which has been separated by the spectral device into its spectral components and which has been scatter-reflected by a material being subjected to thickness measurement, said photodetector receiving only scatter-reflected light. An operation processing device calculates either one of variables a* or b* of an L*a*b* colorimetric system or either one of variable u* or v* of an L*u*v* colorimetric system on the basis of information about the light which has been scatter-reflected by the material. The information is received from the photodetector. A thickness calculating device calculates the thickness of the material from the value of the variable calculated by the operation processing device.

Abstract: An image sensing apparatus of the type employing resolving and sensing means is provided with sensing means of selected size and geometry to allow approximation of arbitrary filter response. The sensing means of selected size and geometry may be incorporated into compact, self contained image resolving and sensing apparatus having a transparent substrate for resolving an incident image by refraction, diffraction or other suitable mechanism. The sensing means may be located directly on a surface of the transparent substrate. Logic and select circuitry may be integrally and simultaneously formed with the sensing means. The size and geometry of the sensing means may enable approximation to color inhibition and other effects to allow approximation of the spectral response of the human eye.

Abstract: A method for generating the characteristics of a set of colors involves selecting at least two, and typically more reference colors. Each of the selected reference colors is described by a set of color characteristic data indicating the reflectance of each color at each of a set of predetermined wavelengths; and descriptions of the intermediate color samples are generated by computer the relative proportions of each base color which characterizes each intermediate color and calculating a reflectance value at each wavelength for the color to be generated proportionate to the reflectance values for each base color at the corresponding wavelength. A set of color samples is created as a result of the method for generating the characteristics of the colors and arranged in a geometry indicative of the method.

Abstract: A spectral sensitivity correcting device in a photoelectric tristimulus colorimeter which comprises three light receiving systems for the measurement of tristimulus values. Signals indicative of respective outputs from two of the light receiving systems multiplied by predetermined correction coefficients are added to or subtracted from an output from the remaining light receiving system so that spectral sensitivity characteristics of the remaining light receiving system can approach predetermined spectral sensitivity characteristics.

Abstract: A portable colorimeter for characterizing the optical properties of a colored surface and in particular a colored surface containing metallic or pearlescent particles, which employs three multiangular spectrophotometric measurements to derive color constants for the surface. The colorimeter is a compact integrated unit housing irradiation, detection, control, analysis and display means and employs three illumination angles, preferably -30.degree., 0.degree., and 65.degree., and one detection angle, preferably 45.degree., all measured from the sample normal. The method includes determining the tristimulus values of the color of the sample surface from low resolution spectral reflectance data preferably using twelve detector elements.

Abstract: A light measuring device wherein a correct measured value can be obtained even if incident light varies in time or a luminance or brightness of an object for measurement is insufficient. The device comprises a branched optical fiber of a random specification having therein three mutually independent light transmission paths for introducing light from a common input end to three output ends. The input end of the optical fiber is located at a slightly defocused position of an objective lens while the output ends are individually opposed to three light receiving elements having different spectral sensitivities. Three components of light are simultaneously converted into electric signals and then into digital values by circuit means each including a double integration analog to digital converter. When a luminance is insufficient at a light receiving element, the gain of the associated analog to digital converter can be adjusted so as to assure appropriate measurement of light.

Abstract: The invention relates to a method and to apparatus for influencing the colour appearance of a coloured area made up of at least three chromatic separation colours in a printing process, on the basis of densitometric or colorimetric measurements, in which the inking is influenced as a matter of priority in at most two chromatic separation colours as a function of the coloured proportion of a sum vector which is determined starting from density value differences or colorimetric difference values in a colour space and broken down into a grey proportion which only affects brightness and a coloured proporation relating to at most two chromatic separation colours. In this way an improved and in particular faster influence on a colour appearance of the coloured area is achieved in a printing process.

Abstract: A colorimetric circuit comprising three detectors for detecting red, green and blue components respectively, a memory for storing the outputs of the detectors sampled at the same instant in logarithmically compressed form, and a control circuit for reading out the contents of the memory in sequence, thereby it being made possible to improve the accuracy of colorimetry.

Abstract: An apparatus for determining and displaying selected characteristics of a film formed on the surface of a glass ribbon includes a scanning head mounted on a track for movement above the filmed surface of the glass ribbon. The scanning head has a source of light pulses generated from a tungsten lamp and chopper, filtered to simulate daylight and focused on the filmed surface. An integrating sphere is also mounted on the scanning head and has an entrance port formed in a wall thereof for collecting a portion of the light being reflected from the surface. Optically filtered detectors mounted in detector ports formed in the wall of the sphere generate output signals representing the "Y" and "Z" components of the collected light on the CIE X,Y,Z, tristimulus scale.

Abstract: Apparatus for determining displacement of an object comprises a light source (1) for propagating polychromatic light along a path to a detector (7). Radiation modulation means such as a filter (5) is provided in predetermined fixed location with respect to the source (1) and the path of the light is adjusted in response to a displacement of the object such as to vary the distributed spectral content of the light reaching the detector (7). The detector comprises first and second photoresponsive elements (10, 11), of differing responsivity with respect to wavelength, and a microprocessor (14) receiving signals from the photoresponsive elements. The microprocessor calculates the color of the light incident on the detector (7) as represented by two or more parameters on the chromaticity (CIE) diagram, and interprets the color of the light incident on the detector (7) in terms of the displacement of the object.

Abstract: A half mirror and two dichroic mirrors having different characteristics are provided on an optical path of measurement light from an object, and four sensing devices are provided on optical paths of reflected or transmitted light from these mirrors. Calculations are performed on the outputs of the four sensing devices, and the resultant values are compared with parameters stored in a microcomputer to thereby effect color distinction.

Abstract: A photoelectric colorimeter which comprises a photoelectric conversion section including an optical filter to analyze light coming from a test piece and a reference calibrating sample into primary color elements, and a photosensor to convert each of said primary color elements into an electric signal; and a data processing section including a calibration constant calculating device for calculating a calibration constant for each of a plurality of reference calibrating samples on the basis of a calibration point of each of the reference calibrating samples and an information inputted from said photoelectric conversion section, a chromaticity point calculation device for calculating a chromaticity point of the test piece and that of each reference calibrating sample, a memory device for memorizing the calibration constant and calibration point of each of the reference calibrating samples, a device for estimating a new calibration constant suitable for the chromaticity point of the test piece between the respect

Abstract: A method of determining the color difference between two similar colors including the steps of determining the tristimulus values for a reference color with which another color is to be compared, providing a planar chromaticity diagram for the values other than brightness in which the values for the reference colors are at the origin and the abscissa and ordinates of the diagram, determining the hue of the reference color and plotting in said diagram an equi-hue line, determining the tristimulus values for the other color to be compared to the reference color and plotting the values other than brightness on the diagram, plotting an equi-saturation line on the diagram perpendicular to the equi-hue line and extending through the origin, plotting lines parallel to the equi-hue and equi-saturation lines through the position of the plotted values for the other color and extending across the equi-hue and equi-saturation lines, so that the difference in the tristimulus values for the other color from the reference c

Abstract: An improved process for matching the color characteristics of a paint containing film forming binder, a liquid carrier, colored pigments and flake pigments to the color characteristics of a surface layer that contains flake pigments; the improvement comprises the following:adding to the paint a dispersion comprising a liquid carrier, a dispersing agent and transparent or semitransparent extender pigments or rigid or semirigid organic particles, particularly preferred are, hollow glass spheres, in an amount sufficient to match the color characteristics of the surface layer.

Abstract: There is provided a color image data processing method for reproducing a color image by use of micro color points of a plurality of colors. The processings for every region to obtain the areas of the color points are performed in parallel irrespective of which region in a plurality of regions on the chromaticity chart the color which should be reproduced belongs to, and among the respective processing results, the color points whose areas were determined to be positive values are used, thereby reproducing a color image.

Abstract: In electronic reproduction technology, a recognition circuit for hues and colors in colored surfaces is provided. Before the actual hue recognition, the hue to be recognized is selected and its prescribed or measured color values of the RGB color space are transformed by a first color transformation into chrominance values of the chrominance/luminance color space, whereby the transformation coefficients are defined such that the transformed color locus of the hue to be recognized lies on a rotated X'Y' color coordinate system in the chrominance plane. During the actual hue recognition, the colored surface is opto-electronically scanned and the measured color values acquired are transformed into chrominance values by a second color transformation with the transformation coefficients defined in the first color transformation.

Abstract: A method for measuring the color difference betweeen a sample dye and a standard dye by testing the color properties of both dyes, which comprises determining, in advance, the relation of the color difference of dyeings (between the standard dye and the dyes of the same family) to the color difference of dye solution (between a standard dye and the dyes of the same family) using the standard dye and two or more, preferably several, representative samples arbitrarily selected from plural lots of dyes, then calculating the color difference of dye solution between the standard dye and a sample dye, and predicting the color difference of dyeings from the calculated color difference of dye solution by referring to the relation obtained.

Abstract: A method for measuring the color difference between a sample dye and a standard dye by testing the color properties of both dyes, which comprises measuring the distribution curve of absorbance of individual components of the dye; determining the relationship between the color difference of dye solution and the color difference of dyeings with respect to the standard dye and representative samples arbitrarily selected plural lots of dyes; and predicting the color difference of dyeings from the color difference of solution between the standard dye and the sample dye.

Abstract: A color sensing device comprising four photo-electric transducers formed on a semiconductor substrate, an interference filter provided on the light receiving face of each transducer, a colored filter for selecting a specified transmission band of the interference filter, and three electrodes for delivering electric signals from the transducers individually, one of the electrodes being provided for two of the transducers in common. The transducers each have the area of its light receiving face so determined as to exhibit spectral sensitivity characteristics matching the color matching function of the CIE (Commission Internationale de l'Eclairage) XYZ colorimetric system.

Abstract: A color analyser measuring the light intensities of at least three different colors within the spectrum of the incident light, and relating these measurements to values programmmed before. Those color components of the incident light that have to be influenced in order to conform to the preprogrammed relations are indicated by means of a color star, consisting of three rows of light sources (23, 24, 25) of appropriate colors. While influencing the color of the light with correction filters the operator views the change simultaneously at the color star. It is indicated in such a way that the light sources of the color star are extinguished as soon as the preprogrammed relations between the colors are satisfied, notwithstanding the absolute value of light intensity. An automatic exposure time meter is built in, also controlling an electronic timer (32).

Abstract: This specification discloses a method and means for color detection and modification wherein the recognition of color is based on the definition of a three-dimensional color sub-space within a three-dimensional color universe. Chromaticity values are digitized and modeled as a function of brightness or luminance. Three eight-bit words (each having 256 values) are stored for each pixel of a digitized color picture. The first value is an approximation of luminance, while the second and third values represent variations of chromaticity or chrominance. Over sixteen million combinations of color values are available for each of over one million pixels in a 1024.times.1024 pixel array image. Pattern recognition techniques are used to determine if a given color value lies within the three-dimensional color sub-space. Additional means and method are disclosed to modify or manipulate the color defined by the color sub-space.

Abstract: An improved method for instrumentally characterizing the optical properties of a surface containing metallic particles such as a paint containing metallic flakes by using multiangular spectrophotometric or colormetric measurements to derive color constants for the paint, wherein the improvement comprises using three multiangular measurements, preferably 15.degree., 45.degree. and 110.degree. as measured from the specular angle.

Abstract: An apparatus including a white light and first, second, and third filters through which the white light is transmitted is utilized to sequentially irradiate a solar cell. The light impinging upon the solar cell from the first, second, and third filters has first, second, and third "tristimulus" distributions. The resulting first, second, and third electrical output quantities produced by the solar cell are measured and utilized to compute normalized spectral response coefficients by normalizing each of the electrical output quantities with respect to the sum of the three. First, second, and third response differences are obtained by subtracting the first, second, and third response coefficients from first, second and third response coefficients previously obtained from a reference solar cell.

Abstract: An apparatus and a method for the recognition of colors on a colored image illuminated with a light source of a known spectrum composition, wherein the intensities of three primary colors are measured opto-electronically as color components, which represent the spatial co-ordinates of the color locations in a color space. Prior to color recognition the color components of at least one characteristic test point in each color or color region, which is to be recognized, are measured and noted. The test color components represent the corresponding test color locations in the color space. An identification symbol is assigned to each color component triplet of the test points and noted too.

Abstract: A trichromatic colorimeter for obtaining the CIE chromaticity coordinates for an object to be measured. By utilizing a logarithmic compression type light measuring circuit, a higher accuracy and measuring range are obtainable in comparison to prior art linear light measuring type colorimeters.