Abstract:
Apparatus and methods for wavelength-dependent detection are provided. A detector includes a hybrid filter having unpatterned and patterned filter layers and at least one light-detecting sensor that detects light in first and second wavelength bands from the patterned filter layer of the hybrid filter. The unpatterned filter layer passes light in two nonoverlapping wavelength bands relative to light in wavelength bands between or among the nonoverlapping wavelength bands. The patterned filter layer includes first and second regions configured respectively to pass light in the first and second wavelength bands of the nonoverlapping wavelength bands passed by the unpatterned filter layer.
Abstract:
A method and apparatus for color measurement using a physically distributed multiplicity of sensors. Broad band illumination is provided to irradiate a test pattern. The sensors are used to measure color characteristics of discrete areas of a region of the pattern that has an intended single color by providing the pattern and sensors arrayed in a substantially matching geometric configuration.
Abstract:
The invention provides an image processing apparatus including a region specifying unit for specifying a measurement-object region from an image; a measurement-region defining unit for defining at least one measurement region in the specified measurement-object region; and a characteristic-sample selecting unit for respectively selecting, from a plurality of characteristic samples that are registered in advance, at least one characteristic sample that is close to each measurement region.
Abstract:
An exemplary system to provide visible lighting of a selectable spectral characteristic (e.g. a selectable color combination of light) uses an optical integrating cavity or other diffuse mixing element to combine light of different colors from different color LEDs. Amplitude modulation of pulsed operation the light sources, e.g. pulse amplitude modulation added to a baseline forward bias current for each of the LEDs, controls the amount of each light color supplied to the diffuse mixing element and thus the amount included in the combined light output of the system. A color sensor may provide feedback as to a color characteristic of the combined light, for closed-loop control of one or more of the pulse amplitude modulations. Examples are also disclosed that utilize phosphor doping of one or more of the system's reflective elements, to add desired wavelengths of light to the combined output.
Abstract:
To generate a reference database for a particular sensor in a multiple LED spectrophotometric system with a reduced number of test measurements taken from training samples, a first set of reflectance reference measurements are generated from a test target on to a reference sensor from a plurality of different LED emissions. A first spectral reconstruction reference matrix is computed comprising an operational characterization of the reference sensor from the first set of reflectance reference measurements. A second set of reflectance reference measurements from the test target is generated from a second subject sensor whose operation is to be personalized by the objective reference database. The second set of reflectance reference measurements are less in number than the first set. A second reconstruction matrix is computed comprising an operational characterization of the subject sensor from the second set of measurements. The second reconstruction matrix is adjusted by relating the second set of reflectance measurements to a set of corresponding reflectance measurements of the reference sensor, whereby the adjusting of the second matrix comprises computing an optimal solution spectral reconstruction matrix for the second sensor. The reference database is generated from the optimal solution spectral reconstruction matrix.
Abstract:
An illumination arrangement intended for use in a spectrophotometer is constructed as a linear array of light emitting diodes (11), whereby many individual light emitting diode chips are tightly packed along a small, narrowly defined straight or circular line and at least partially cast into a resin, in which at least regionally a converter material is included for the conversion of the light emitted by the light emitting diodes into other wavelength ranges. The light emitting diodes (11) have different spectral characteristics. UV light emitting regions and non-UV light emitting regions as well as regions covered with colour filters and/or polarization filters are provided. The illumination arrangement can include white emitting regions and narrow band emitting regions constructed especially for colour density measurement, whereby the narrow band regions can also be realized as narrow band converters. Ortho-silicate illuminants (BOSE) are preferably used as converter materials. The light emitting diodes (11) are preferably individually or groupwise selectively controllable. The illumination arrangement in accordance with the invention is clearly superior to conventional illumination arrangements with respect to performance, precision and universality of application.
Abstract:
A hand-held colorimetric device (101) suitable for use by blind or colour-blind individuals to determine the colour of a surface-under-test (SUT), for example of a fabric, has an aperture (110) which, in use, is covered by the SUT (113) whose colour is to be determined. Six LEDs (115A, 115B, 116B, 117A and 117B) arranged in pairs (115A/115B, 116A/116 B, 117a/117B) emitting red/orange, green, and blue light illuminate the SUT and diffuse reflections therefrom containing red/orange, green, and blue spectrum sample values are used to determine the luminous reflectivity and chromaticity values for the colour of the SUT. The measured values are compared with colorimetric values of reference surfaces to determine the colour of the SUT. The colorimetric device may output the name of the colour aurally.
Abstract:
RGB filter set and color estimation performance for RGB LED color sensing is provided. A criteria function describing an error between desired color matching functions and a spectral response of an RGB filter set is constructed. RGB filter set response characteristics based on the criteria function are then determined. Finally, color estimation parameters for substantially optimal color estimation with the RGB filter set are determined based upon the determined RGB filter set response characteristics. Computer readable code for constructing a criteria function is provided. Computer readable code for determining RGB filter set response characteristics is also provided. Finally, computer readable code for determining color estimation parameters is provided.
Abstract:
A full width array spectrophotometer for full width scanning color analysis of color test targets, with one or two substantially linear elongated arrays of closely spaced multiple LED illumination sources of plural different color emissions in a multiply repeated pattern of at least three or four different colors transversely spanning a printer paper path and sequentially illuminated to illuminate a transverse band across a printed sheet moving in the paper path, and a corresponding elongated low cost light imaging bar with a parallel and correspondingly elongated array of multiple closely spaced different color sensitive (three or four rows of color-filtered) photodetectors, which imaging bar is positioned to detect and analyze light reflected from the transverse sequentially illuminated band.
Abstract:
A color measurement system includes a hand held color measurement instrument, which may be provided with a wireless interface to a computer. The color measurement system includes a scanning guide for holding the hand held color measurement instrument in proper alignment with a color target. The scanning guide includes a calibration reference to allow convenient calibration of the hand-held color measurement instrument. The hand-held color instrument includes an illumination ring to provide visual feedback to the user. The color of the illumination ring changes in order to display a color similar to that being read by the hand-held color measurement instrument. Color management profiling of the hand held color measurement instrument illumination ring improves the color rendition capability of the illumination ring.