Eastman-kodak Company

Light Source Computer Images, Inc.

Light Source Acquisition Company

Fresh Roast Systems, Inc.

Other

X-rite Gmbh

Edward M Granger

John F Hamilton, Jr

Robert L Cook

Philip Alan Torbet

Frederic H Metildi

Eric M Herrmann

Larry G Wash

Lawrence D Baca

Akin Dirik

Nelson Offner

Badhri Narayan

James E Roddy

Thomas W Dey

Philip F Marino

John Patrick Spence

Scott J Daly

Robert Dean Fiete

Donald E Vandenberg

John G Pitek

William D Humbel

Harvey E Rhody

Roger A Allington

Joel K Mason

Charles E Rinehart

Sara T Wellman

Peter A Jones

An efficient technique for calibrating a scanner relative to a particular colorant set having N primary colorants. Once the scanner is calibrated, the scanner's device-dependent tristimulus values for an arbitrary color are transformed to a device-independent representation of the arbitrary color in a computationally efficient manner. The technique exploits the fact that the color space defined by the primary colorants can be advantageously partitioned, with each partition being represented by a transformation matrix that accurately characterizes the transformation for that partition of the space. The partitioning is characterized by a set of M key colors (in a specific embodiment, M=2N), each of which defines a boundary between adjacent partitions.

Scanner calibration technique

Bulk material formed by a multiplicity of individual moving particles is heat-treated by directing a light beam into an observation volume of the material and generating light reflections off at least one particle in the observation volume. A characteristic of the light reflections which is indicative of a desired extent to which the material is to be heat-treated is identified and the material is subjected to a heated environment and thereby heat-treated. The light reflections are monitored for the characteristic, and subjecting the material to the heated environment is ended in response to detecting the characteristic of the light reflections.

Method of terminating roasting of bulk materials in real time on basis

A reflectometer for use with a roasting system includes a laser diode, a lens and a photodetector. The laser diode emits a laser beam having a wavelength corresponding to the maximum actinic response of the items being roasted. The laser beam is reflected off a mirror into a collecting volume of the items being roasted. The items being roasted then reflect light through the lens and to the photodetector. The system also includes a cross polarizer and a narrow-band filter between the lens and photodetector in order to filter undesirable reflected light. The collecting volume and the detector are within the searchlight cone defined by the lens and its focal point such that the reflected light from the collecting volume has a constant illumination.

Reflectometer for a roasting system

A desktop color measurement system that includes an instrument capable of making color measurements. The system includes a host computer and a digital color sensor (DCS) in communication with the host computer. The DCS includes optical elements for making spectral measurements, and control electronics for controlling the optical elements. In a specific embodiment, the DCS is dedicated to the mechanics of acquiring the raw data. The host computer, which may be a personal computer, performs all the calculations needed to convert raw measurement values into spectral data and other color representations such as tristimulus values and density. This also allows the system to function as a calorimeter and a densitometer as well as a spectrophotometer. The DCS control circuitry includes non-volatile writable storage for information obtained during a factory calibration procedure, which information allows the user to recalibrate the DCS in the field.

Color measurement system including a digital color sensor and a host

A technique for calibrating a scanner wherein once the scanner is calibrated, the scanner's device-dependent tristimulus values (e.g., RGB) for an arbitrary color are transformed to a device-independent representation (e.g., XYZ) of the arbitrary color in a computationally efficient manner. The scanner is characterized in a manner that a corrected device-independent representation of an arbitrary scanned color can be determined on the basis of a pair of chromaticity coordinates in a chromaticity space having (i) a pair of chromaticity coordinates that span hue and chroma (saturation), and (ii) a lightness coordinate that is a luminance correlate (monotonic function of luminance). A look-up table stores XYZ values and a lightness value. A set of XYZ values and a lightness value are retrieved from the table as addressed by a pair of chromaticity values corresponding to the scanned value. The XYZ values from the table are then scaled by the ratio of the scanned lightness value to the lightness value from the table to provide the XYZ values for the arbitrary color.

Scanner calibration and correction techniques using scaled lightness

A target output device such as a printer is characterized in a manner that primary colorant amounts can be determined on the basis of a pair of chromaticity coordinates in a chromaticity space having a pair of chromaticity coordinates that span hue and chroma (saturation) and a luminance correlate (monotonic function of luminance). Lightness (or darkness) of the colors is handled largely independently. This makes it possible to store the colorant information in a two-dimensional table indexed by chromaticity coordinates. The information in the table is for colors that are characterized by the highest luminance that the target printer is capable of rendering for a given chromaticity (hue and chroma).

Appearance-based technique for rendering colors on an output device

The present invention provides a method and apparatus for accurately matching colors. The color matching system includes a host computer and a color input device in communication with the host computer. Preferably the color input device is capable of obtaining spectral data, such as that obtained using a spectrophotometer. The host computer includes a color library, a color management system, a monitor, and a user interface. In one aspect of the invention, the user selects a target color, a color library to use for matching, a color distance tolerance, and a light source under which the colors are to be matched. The target color is compared to the colors in the library and the color or colors in the library that are within the specified color tolerance are reported. In a second aspect of the invention, the user selects a color and two illuminants. The color under each of the two illuminants is compared and the color distance between the two is reported. In a third aspect of the invention, a selected color is transformed to the color space of a designated printer and then back-transformed to the color space of the monitor and displayed. The displayed color represents a simulation of the selected color as it would appear if printed.

Apparatus and process for a digital swatchbook

A technique, including apparatus and accompanying methods, for use in a tile oriented digital screener for suppressing screener induced image artifacts through use of 'blue noise' based selection among a number of different halftone dot fonts. Specifically, in producing a screened halftone dot pattern for any density value, a two-dimensional seamless matrix of blue noise correlated uniformly distributed integer values is used to select one of a number of different halftone dot fonts that will be produced for any halftone density value. The amount of blue noise in the matrix is specifically tailored, both in amplitude and frequency response, to substantially suppress all low frequency image artifacts and place resulting screening errors at sufficiently high spatial frequencies so as to render these errors essentially invisible to a human observer. Across identical density values, these fonts illustratively contain symmetric edge variations, and substantially constant dot area and dot center locations. Through use of this technique, any noticeable increase in image granularity is also advantageously avoided.

Blue noise based technique for use in a halftone tile oriented screener

Apparatus and associated methods employed therein, for objectively providing an accurate appearance match between images produced by two imaging systems (e.g. a target image produced by one such system, e.g. a press sheet (140) generated by a printing press (130), which is to be matched by a replica image produced by another such system, e.g. a proof (120) generated by a color halftone proofing system(110)) and thereby calibrate the performance of one imaging system, e.g. the proofing system, to that of the other system, e.g. the printing press. Specifically, measurement data, such as illustratively densitometric N,R,G,B measurements, is obtained for the same portions of the press sheet and proof. This data is then transformed into a color space which encodes color information in a pre-defined manner that approximates color preferences inherent in human color interpretation. Thereafter, through use of a pre-determined model of the proofing system, incorporated into pre-defined matching principles which objectively and quantitatively define an accurate appearance match between the images produced by both systems, changes in operational settings for the proofing system, such as solid area densities and tint dot areas, are determined which will calibrate the response of the proofing system to that of the press. Consequently, tone and color rendition produced by the proofing system is modified to provide an accurate appearance match to that obtained, from a common image source, on the press, given the judgmental preferences of a human observer and the performance limitations of the proofing system.

Technique for use in conjunction with an imaging system for providing an

A new scene-based wavefront sensor is useful in a device as, for example, a telescope or camera that provides information of aberrations (e.g., out-of-focus condition) directly from light received from a scene in object space being scanned by movement of either the wavefront sensor or elements in the scene. The wavefront sensor includes an imaging system defining a predetermined pupil, a light opaque material having a surface and defining a probe hole (pinhole) therethrough, a linear image sensor array, a relay lens, and a pupil sensor array including a plurality of light sensors. The probe hole and image sensor array are disposed at a focal plane of the imaging system while the pupil sensor array is disposed at a focal plane of the pupil of the imaging system. As the wavefront sensor is moved to scan a predetermined scene in a direction normal to the orientation of the image sensor array, output signals of light intensity versus time detected by each of the sensors of the image and pupil sensor arrays are transmitted to a controller. The controller uses such output signals for determining if, for example, aberrations exist in the scanned scene and for generating control signals to a user device for correcting for such aberrations.

Scanning scene-based wavefront sensor having a linear image sensor array

A method for determining a radiation imaging system focus error, that employs a novel focus sensor. In a preferred embodiment, the novel focus sensor comprises two beamsplitters, a spacer, and three detectors comprising CCD arrays. The three detectors are constrained to satisfy radiation path length specifications, with respect to the beamsplitters and spacer. In the method, the focus sensor may be aligned in an unused portion of an imaging system radiation field. The detectors simultaneously image the same scene, sampling it at three different focus positions. The sampling action becomes a basis for generating a parabolic curve; a maximum of the parabolic curve is a measure of the imaging system focus error.

Method for determining an imaging system focus error

A flat bed scanner for accurate scanning of document information includes a means for moving an image-bearing member, such as a document, under a slot in a bottom of an enclosure. The enclosure has a diffusely-reflecting internal surface so as to define a light-integrating space within the enclosure. The slot and a window in the enclosure side provide access for light between the exterior and the interior of the enclosure. Means are provided for directing a scanning beam of light through the window and the slot to form a moving spot on a portion of the document. Detector means are provided for sensing the intensity of light diffusely reflected into the enclosed space from the spot. An electronic signal, related to the intensity of the reflected light, is produced to describe the scanned document information. To compensate for variation in the light path length due to an angular scanning motion, a beam path length compensation means is included. The compensation means includes a movable tapered-thickness optical plate which is positioned in the light path. As the plate is moved in a direction transverse to the light path direction, the beam encounters a varying plate cross-section such that the beam focal point changes proportionally. Movement of the plate is synchronized with the motion of the scanning beam.

Flat bed scanner

A color imagery compression/decompression mechanism employs a contrast sensitivity function model of the human visual system for color images, to derive normalization values for compressing chromatic components of the color imagery data. The CSF model is defined in terms of an ADT color space transform (15), the chromatic channels of which conform with the band-limited sensitivity of the visual system. The transform for obtaining the ADT components is executable by reduced complexity logic operators. Each of the ADT components is block transform coded using DCT transform coefficients (18) that are normalized (24) in accordance with a `weighted` (46, 45) CSF model (42) of the human visual system, which effectively performs a low pass filtering of the chromatic (DT) channels. This low pass filter-weighting of the normalization values in the compression, transmit end (10) of the system produces a set of normalized coefficients which effectively blur the image and reduce the entropy in the chromatic channels and may be implemented using a Gaussian function. In the decompression process at the receiver (14), a corresponding set of denormalization coefficients (32), which are generated in accordance with the same chromatic CSF model of the human visual system, are not weighted, so that the cascading of the normalization and denormalizing operators in the transmitter and receiver yields a product less than unity, simulating the entropy-reducing effect of subsampling.

Growing community of inventors

Rochester, NY, United States of America

Edward M Granger