Abstract:
A colorimeter for reading color bars of printed sheets or the like includes a longitudinally extending base including a paper stop along which a sheet to be tested for color may be positioned. An autonomously operating colorimeter head is moved along the base in a direction parallel to the edge of the sheet by means of an electric motor mounted on the base and driving an helical thread lead screw engaging an X-axis carriage supporting the head. The head is moved by operation of the lead screw in a direction parallel to the edge of the sheet, referred to as the direction of the X-axis. The head includes an electric motor and a Y-axis transport supporting an optics unit. The optics unit is moved within the head in a direction parallel to a Y-axis, extending perpendicularly to the X-axis. The optics unit is preferably a spectrophotometer including a rotating wheel provided with a plurality of individual filters, spaced apart along the periphery of the wheel. The individual filters each pass light of a predefined wavelength onto a single photodetector and the signal derived from the photodetector is integrated over a period of time to provide an output signal representative of the intensity of a particular wavelength.
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 system includes a portable spectrophotometer connectable to a general-purpose computer. The portable unit includes a microprocessor with a read-only program memory storing machine executable instructions to implement data processing for color measurement purposes and input/output functions including key reading and data transfer functions and display functions. A random-access data memory is used to temporarily store process data for later transfer to the general-purpose computer. An editor program and a compiler program in the general-purpose computer may be used to generate a program for the microprocessor using high-level, generalized commands. After such a program has been written and compiled in the general-purpose computer, it is transferred to a command buffer area in the random-access data memory of the microprocessor. The microprocessor, in its program memory, includes a command interpreter including a predefined sequence of machine executable instructions for each generalized command. When executed, the command interpreter reads a generalized command from the data memory and, if necessary, updates relevant data pointers and executes the predefined sequence of machine executable functions in the program memory corresponding to the generalized command being processed. A user, using the general-purpose computer, may specify any desired sequence of measurement operations by specifying functions to be performed by the microprocessor, including the display of prompts to the operator of the portable spectrophotometer to instruct the operator to perform various specified operations.
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:
An apparatus for measuring a diamond color comprises a light source composed of a lamp and an integrating sphere for diffusing light therein emitted from the lamp; a diamond holder including diamond supporting head means and suction base means, thereby positioning the table facet of the diamond in the integrating sphere for allowing the diffused light from the light source to fall on the table facet of the diamond; a monochromator for separating a beam of light as it emerges from the diamond through the table facet side into a spectrum; a photodetector for detecting the light from the monochromator; variable slit means disposed in at least one of the monochromator and the photodetector for adjusting the size of the beam of light to a diameter of the diamond; a measurement unit for controlling at least the monochromator to obtain a spectrum of the light which has passed through the diamond; and an arithmetic unit for deriving tristimulus values X, Y and Z from the spectrum of the light from the diamond; which is able to measure the colors of brilliant-cut diamonds easily and objectively.
Abstract:
The invention relates to the measurement of the shade of a particle. The particle is illuminated with light of variable intensity and viewed against a background level of illumination. A measurement is made of the ratio of time for which the intensity of light from the particle exceeds the intensity of the background to obtain a measurement of the shade of the particle.
Abstract:
A novel apparatus for the measurement of color of a sample which comprises an illumination means to illuminate the sample, an electro-optical sensing head to receive the light from the illuminated sample and to output electronic signals and an electronic processing unit to process the signals. The light source may in the preferred embodiment be the sun or the sample itself and a reference optical path is used for reference which is the same optical path as the optical path from the light from the sample. The tristimulus values X, Y, Z and the chromaticity coordinates x, y of the sample with respect to the CIE standards for luminance and chromaticity values are produced for accurate color measurement.
Abstract:
A novel apparatus for the measurement of color of a sample which comprises an illumination means to illuminate the sample, an electro-optical sensing head to receive the light from the illuminated sample and to output electronic signals and an electronic processing unit adapted to process the signals. The system uses, in the preferred embodiment, a moving spatial filter to modulate a spectrum and a masking means to selectively mask the light from the modulated spectrum. A reference optical path and reference light signals are produced for subsequent processing with the light from the sample, corrected for any errors produced and processed in an analogue electronic unit to produce the tristimulus values X, Y, Z and the chromaticity coordinates x, y of the sample with respect to CIE standards for luminance and chromaticity values.
Abstract:
Disclosed are a colorimeter and a reflectivity measuring method based on a multichannel spectrum. The colorimeter includes a main unit and a calibration box, wherein the main unit includes an integrating sphere, a light source and a main sensor, a detection hole is formed in one side of a top of the integrating sphere, a light-through hole is formed in a side of the integrating sphere, and a measuring port is formed in a bottom of the integrating sphere, the light source is arranged outside the light-through hole, and the main sensor is arranged outside the detection hole; the calibration box includes a housing and a white board arranged at a top of the housing, the white board is correspondingly matched with the measuring port, and the calibration box is connected with the main unit; the sensor is a multichannel spectral sensor.