摘要:
What is disclosed is a method for maintaining consistent color output across printers even when the inline sensors have differences in accuracy due to various technical and environmental factors. A spectrophotometer is used to measure the color quality of printed references. Adjustments are then iteratively made until reference charts of desired color quality are obtained. The printed reference allows one to achieve relatively high system performance by removing sensor inaccuracies. Using the printed reference measured by the inline sensor control systems of each machine are calibrated. At customer sites and at suitable intervals, a reference document can be read using the inline sensor on a reference machine and any differences from expected values can be calibrated out. The present method is also applicable to other color management functions such as memory color and automatic profile generations using inline/offline sensors and can be used for determining reference values while calibrating control systems of printers over a wide range of applications.
摘要:
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.
摘要:
An image transfer apparatus with a scanner and a spectrophotometric sensor interacting logically with the scanner. When the scanner scans a medium containing a color image, the spectrophotometric sensor interacts with the scanner to aid in the automatic selection of a scanner color correction corresponding to the medium being scanned.
摘要:
The present disclosure is directed to a system and method to render spatially uniform memory colors when images printed with CMYK primaries are not rendered uniformly due to output device quality errors. The disclosed method uses an array of sensors to scan a test image. Colors of interest are printed at the desired location first and then adjusted (iterated) to achieve a desired output quality. Iterations are carried out on the image on desired memory colors at the spatial resolution available in the measurement system. Colors of pixels are modified based on position where the pixels will be rendered, thereby compensating for any position/process related differences. Also disclosed is a process for incorporating modified memory colors before rendering, and the extension of memory color concepts to adjust colors for the uniform blocks (not edges), with uniformity defined by user definable thresholds.
摘要:
This disclosure provides methods, apparatus and systems for generating a profile for a printing device. Specifically, the profile is generated by selecting a GCR profile from a plurality of GCR profiles and mapping a plurality of nodes to a device dependent color space as a function of the selected GCR profiles.
摘要:
Identifying the substrate type of a target substrate before patterning by a marking engine produces an opportunity to adjust the marking engine. The adjustments can enable the marking engine to produce higher quality work. The target substrate's substrate type can be automatically identified by obtaining its characteristics and submitting them to a classifier. A spectrophotometer can measure a substrates reflectance spectrum, which is a good characteristic for use in classifying. Classifiers can be based on known distance or correlation measures.
摘要:
A marking engine forms one or more toned patches and/or images on a photoreceptor transfer device such as a photoreceptor belt or drum, either within or outside a main image area. A sensor illuminates the tones patches and/or images on the photoreceptor transfer device using wavelengths outside the photo response range of the photoreceptor transfer device, thereby allowing reflectance values for each toned patch and/or image to be measured without generating ghost images on the photoreceptor transfer device. The sensor supports collection of measured reflectance values from single-color, mixed-color; and multi-separation image-on-image toned patches and/or images directly from the photoreceptor transfer device at rates as high as one or more times per revolution of the photoreceptor transfer device. The measured reflectance values may be used to generate and/or update color stabilization tone reproduction curves.
摘要:
Multiple input patches are received on an output media, which patches are characterized by print density representing a document processing system's response to different input grayscale values over a potential response space. Values associated with the print density of each input grayscale value are measured. Reference Engine Response Curves are determined from the measured print density values and input gray scale values. A variance data representative of a difference between each measured print density value and a respective reference Engine Response Curve is determined. The variance data is transformed into individual components. Based at least on one selected individual component, a set of calibration compensating Tone Reproduction Curves is determined. The determined calibration compensating Tone Reproduction Curves are applied to input grayscale values.
摘要:
To determine the spectra of objects that have different degrees of fluorescence, a plurality of reference databases are provided, each reference database being suited to a different degree of fluorescence. A most appropriate one of the reference databases is selected based on a predicted degree of fluorescence of an object for which a reflectance spectrum is to be determined. The prediction of the degree of fluorescence may be based on user input, or may be predicted by using a priori information, such as a priori knowledge of media types.
摘要:
A spectral filter includes a two-dimensional array of Fabry-Perot cavity structures, a controller, and a sampling circuit used to switch the Fabry-Perot cavity. The filter receives an incoming image, the sampling circuit switches the cavity to generate a filter image, and the filtered image is detected by the photodetectors to convert a filtered image into digital data. The controller coordinates all the image capture functions of the spectral filter.