X-rite Europe Gmbh

Gretag-macbeth Ag

Carl Zeiss Jena Gmbh

Adrian Von Orelli

Beat Frick

Peter Ehbets

Wilhelm Schebesta

Mark Wegmüller

Bruno Pfister

Eckard Vasold

Michael Lanker

Thomas Kunz

Mario Offermann

Eckhard Vasold

In a method for gauging a color measurement chart which includes at least one row of color measurement fields, a hand-held color measurement device is moved over the color measurement fields and gauges the color measurement fields. The measurement device is guided over the color measurement fields in two measurement runs. In a first run, first color measurement data is measured using a first type of illumination light (typically, white), covering a sufficient portion of the spectrum to enable the fields to be identified by means of the first color measurement data, and the fields are identified on the basis of the first color measurement data. In a second run, second color measurement data is measured using a second type of illumination light (typically, UV), and is then assigned to the color measurement fields on the basis of the fields identified in the first run.

Method and hand-held color measurement device for gauging a color measurement chart

A handheld color measurement device includes a housing in which an optoelectronic measurement unit is located which receives measurement light originating from a measurement object, converts it into corresponding electrical measurement signals and processes these measurement signals into preferably digital measurement data characterizing the color of the measurement object. It further includes passive components required for the realization of different application functions, such as measurement windows and reference standards, which can be selectively positioned into the measurement beam path of the measurement unit. The passive components are positioned in a first housing block () and the opto-electronic measurement unit as a whole in a second housing block (). The second housing block is adjustable into several defined application positions relative to the first housing block, in which application positions respectively one of the passive components is located in the measurement beam path of the opto-electronic measurement unit. This special division into two mutually relatively adjustable housing blocks allows an easy realization of a compact color measurement device suitable for many application functions, which is distinguished by a particular user friendliness.

Handheld colour measurement device

A spectrophotometer for integration purposes includes a measurement head with an illumination arrangement () including at least one fight source () for the illumination of a measurement object located in a measurement plane (M) under an angle of incidence of at least 45&#xb0;, with a pick-up arrangement for capturing the measurement light remitted by the measurement object under an angle of reflection of the essentially 0&#xb0; relative to the perpendicular of the measurement plane, a spectrometer arrangement () with an entry slot () for the spectral splitting of the measurement fight received through the entry slot and captured and with a photoelectric receiver arrangement () exposed to the spectrally split measurement light for conversion of the individual spectral portions of the measurement light into corresponding electrical signals.

Colour measurement device with associated measurement head

A color measurement device includes a color measurement channel () and a control (C), which forms color measurement values from the measurement signals of the color measurement channel and from stored white calibration data. It further includes correction means in order to calculate or correct the color measurement values depending on different distances (a) and/or angles (&#x3b1;) to the measurement object. Because of the special measurement value correction, the color measurement device is especially suited for contactless measurement applications with variable distances and angle orientations relative to the measurement object.

Colour measurement device and measurement process for the device

For the color measurement of samples printed on a substrate including a brightener, a raw spectral reflection factor of the sample is measured in a first measurement by illumination of the sample with light without UV portion. In a second measurement, a fluorescence spectrum of the sample is measured by illumination of the sample with only UV light. The measured fluorescence spectrum is recalculated as a corrected fluorescence spectrum by weighting with spectrally dependent correction factors and, finally, the measured raw spectral reflection factor and the corrected fluorescence spectrum are added to form a corrected spectral reflection factor from which the values characterizing the color of the sample are then calculated. The spectral correction factors are determined during the device manufacture for a certain set of light types and stored in the device.

Process for the colour measurement of printed samples including brighteners

For the colorimetric measurement of a two-dimensional original, the original is photoelectrically scanned pixel by pixel in a first step by way of a color-enabled photoelectric scanning device. A digital color representation of the original is produced from the thereby obtained scanning data. In a second step, suitable measuring positions are determined from the digital color representation of the original by way of a computer using image processing methods. In a third step, the color measuring head is automatically moved under the control of the computer to the so determined measuring positions and the original is colorimetrically measured at those measuring positions. The color data obtained thereby can be further processed, for example for the generation of apparatus profiles for the colorimetric control of output apparatus. The scanning device is preferably a high resolution flatbed or autofeed scanner or a digital camera. The color measuring head is preferably a spectral measuring head. By the comparatively high resolution pixel by pixel scanning of the original, the measuring positions can be very exactly determined without manual input and without time consuming multiple measurements. Furthermore, artifacts caused by dirt can be recognized and corrected.

Process and apparatus for the colorimetric measurement of a two-dimensional original

A spectrometer is provided having a carrier, a light input for measurement light disposed on the carrier, a diffraction grating disposed on the carrier for dispersing the measurement light received from the light input, an opto-electronic detector disposed on the carrier for receiving and detecting the measurement light dispersed by the diffraction grating, at least one optical component for imaging the measurement light on the detector through the diffraction grating, a base board fastened to said carrier for supporting the opto-electronic detector, wherein the opto-electronic detector is fastened at a predetermined position on the base board, and wherein the base board and the carrier include positioning members for relatively positioning the base board on the carrier in a predetermined position. Preferably, the detector is a detector chip excluding a housing and fastened in a predetermined position on the base board. Both, carrier and base board have cooperating positioning members for positioning the base board on the carrier. The base board is preferably an electronic circuit board being fastened to the carrier in such a manner so as to allow a thermal expansion, and wherein the position of the fastening point P relative to the position of the detector on the base board is chosen such that the thermal expansion of the base board substantially compensates the drift of the spectral light component relative to the detector for at least an intermediate wavelength of the measured spectrum, the drift being caused by the thermal expansion of the diffraction grating and the carrier. In addition, the materials of the carrier, the base board, and the diffraction grating are selected with respect to their thermal expansion coefficients such that the temperature drift of the spectrum is substantially compensated for the entire measured spectrum. For most applications, the spectrometer is also sufficiently temperature compensated when using plastic components and is easily and economically produced.

Spectrometer

A measuring device for emitted, remitted or transmitted light from a measuring object is provided having an optical detector for capturing light to be measured, said light being radiated from the measuring object; a spectrometer optically connected with the detector for dispersing the measuring light into its spectral components, said measuring light being captured by the detector, said spectrometer including a photo-electric converter for generating respective analog electrical signals from the spectral components of the measuring light; an analog/digital converter for converting the generated analog electrical signals into respective digital measurement data, said analog electrical signals being generated by the photo-electric converter; a digital computer for controlling the photo-electric converter and the analog/digital converter; a bidirectional interface for connecting the computer with an external computer; and a program for controlling the computer, said program for communicating between the computer and the external computer via the interface, wherein the external computer starts measuring processes and transfers the thus generated digital measurement data to the external computer via the interface. The interface is a USB or Fire Wire interface and the power supply to all electrical components of the measuring device is carried out through the interface. Therefore a power supply circuit is provided which is connected to the interface for generating the necessary supply voltage for each of the individual electrical components of the measuring device from the supply voltage being supplied by the external computer via the interface. The use of a USB or Fire Wire interface allows the processing of the measurement data to be transferred into the external computer, thus allowing a particularly cost efficient manufacturing of the device so that the device becomes available to a wide range of users.

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Zurich, Switzerland

Adrian Von Orelli