Abstract:
Disclosed is an apparatus for measuring on-line the color and color-related properties of a moving sheet. Contrast ratio reflectance measurements are made for providing opacity corrections substantially in real time for a full color spectrum. An optical color sensor in accordance with the invention includes a pair of synchrhonized spectrometers, the first spectrometer being aligned to view a region of the sheet backed with a highly reflective ('white') material and the second spectrometer being aligned to view a region of the sheet backed with a higly absorptive ('black') material. The use of two spectrometers permits substantially simultaneous 'black' and 'white' measurements for a full color spectrum. The optical color sensing system further includes two light sources, a flashlamp and a continuously energized tungsten filament lamp. Light beams from the two sources are combined to form a sheet-illuminating third beam approximating the D65 standard source. The intensity of the flashlamp is electronically controlled to maintain the balance of UV to visible light that characterizes the standard source. The color sensor further includes a sheet backing system including a rotatable standard wheel carrying a white standard tile. Provision is made to permit rotation of the standard wheel and to standardize the sensor off-sheet while maintaining isolation of the white standard tile from the paper mill environment.
Abstract:
A rendering apparatus includes: a radiant-energy calculating device for determining a spectral radiance for each infinitesimal area of an object by using a spectral radiance of a light source irradiating the object, a spectral reflectance in the infinitesimal area of the object, and a spectral reflectance factor in a wide area of the object; a color-specification-value calculating device for calculating color specification values of a colorimetric system on the basis of the spectral radiance obtained for each infinitesimal area; a transforming device for transforming the color specification values into image data for displaying an image of the object; and a display device for displaying the image of the object on the basis of the image data.
Abstract:
In an optical instrument for spectroscopically measuring color and gloss of a sample surface, a fiber optic probe is provided wherein light is transmitted from a light source to the probe through a fiber optic bundle. The fiber optic bundle is arranged to illuminate a surface positioned over an aperture in the probe. Light diffusely reflected from the sample surface is transmitted by a second fiber optic bundle to a spectrophotometer. A small fiber bundle is arranged in the probe to irradiate the surface of the sample at an angle of 60 degrees and a second small fiber bundle is arranged to receive light from the first mentioned small fiber bundle after being specularly reflected from the surface. The second fiber optic bundle transmits the received light to a photodetector in the spectrophotometer to provide an indication of the gloss of the sample surface.
Abstract:
In a real-time color comparator which performs color comparisons of sample objects to a reference color for the purpose of identification, sorting or matching two optical paths (15, 16) are positioned to collect the light from a reference object (12) and a sample object (11). The light outputs from the two paths are directed onto a spectral dispersive element in the form of a concave diffraction grating (20) that decomposes each light signal into its spectral constituents which are imaged on a dual photodetector array (30). The color signature from the reference and the color signature from the sample are compared.
Abstract:
Ein Handgerät zur Erfassung photometrischer Daten verfügt über einen Meßkopf (4) zur Beleuchtung einer Meßfläche und zur Erfassung des remittierten Lichtes. Das vom Meßkopf (4) aufgefangene Meßlicht wird mit Hilfe eines ein Beugungsgitter (55) enthaltenden Monochromators spektral zerlegt. Mit Hilfe eines Photodetektors (62) wird die Intensität des durch eine Austrittsblende (61) austretenden Lichtes erfaßt. Die spektrale Lage des Meßlichtes wird mit Hilfe eines Antriebsmotors (31), der eine mit der Halterung (60) des Beugungsgitters (55) verbundene Gitterwelle (30) dreht, eingestellt. Aus den erfaßten Spektren werden mit Hilfe eines Rechners (63) densitometrische und farbmetrische Größen errechnet, die ebenso wie die erfaßten Spektren auf einem Anzeigefeld (10) darstellbar sind.