Abstract: The present invention relates generally to a printing system, and more specifically to an ordering of color-forming layers in a direct thermal printing medium. The present invention provides a direct thermal print medium with an ordering of the color layers that improves the perceived image sharpness and color uniformity of prints.

Abstract: The present invention relates generally to a printing system, and more specifically to an ordering of color-forming layers in a direct thermal printing medium. The present invention provides a direct thermal print medium with an ordering of the color layers that improves the perceived image sharpness and color uniformity of prints.

Abstract: A method of predicting warps for image registration includes receiving warp data for a first band pair in an N-band system. The method includes fitting a warp model to the warp data to produce an offset profile for the first band pair, predicting a respective offset profile for at least one other band pair in the N-band system, and using the predicted respective offset profile to generate a warp for the at least one other band pair. The method also includes registering images of the at least one other band pair using the warp for the at least one other band pair. In another aspect, a method of predicting warps for image registration includes receiving warp data for m band pairs in an N-band system, wherein m?(N?1) and m>2, to register images.

Abstract: A method of registering images includes identifying a block size for a warp estimation on a block by block basis to improve registration of a first image to a master image, and performing the warp estimation on a block by block basis to produce warp data, wherein the warp data includes a warp vector for each block and its associated uncertainty. The method also includes performing a warp model fit on the warp data to produce reduced noise warp data, and applying the reduced noise warp data to the first image for improved registration of the first image to the master image.

Abstract: A method of predicting warps for image registration includes receiving warp data for a first band pair in an N-band system. The method includes fitting a warp model to the warp data to produce an offset profile for the first band pair, predicting a respective offset profile for at least one other band pair in the N-band system, and using the predicted respective offset profile to generate a warp for the at least one other band pair. The method also includes registering images of the at least one other band pair using the warp for the at least one other band pair. In another aspect, a method of predicting warps for image registration includes receiving warp data for m band pairs in an N-band system, wherein m?(N?1) and m>2, to register images.

Abstract: The present application is directed to systems and methods for print alignment by a continuous feed printer. A sensor of a printer detects a first line of a pattern on a non-printing side of a printing medium, the pattern comprising two non-parallel lines separated by a predetermined distance at a predetermined position of the printing medium. The printer advances the printing medium a first distance, and the sensor detects a second line of the pattern. The printer identifies a horizontal offset of the printing medium from an expected location of the predetermined position proportional to the difference between the first distance and the predetermined distance.

Abstract: The present application is directed to systems and methods for print alignment by a continuous feed printer. A sensor of a printer detects a first line of a pattern on a non-printing side of a printing medium, the pattern comprising two non-parallel lines separated by a predetermined distance at a predetermined position of the printing medium. The printer advances the printing medium a first distance, and the sensor detects a second line of the pattern. The printer identifies a horizontal offset of the printing medium from an expected location of the predetermined position proportional to the difference between the first distance and the predetermined distance.

Abstract: The present application is directed to systems and methods for print alignment by a continuous feed printer. A sensor of a printer detects a first line of a pattern on a non-printing side of a printing medium, the pattern comprising two non-parallel lines separated by a predetermined distance at a predetermined position of the printing medium. The printer advances the printing medium a first distance, and the sensor detects a second line of the pattern. The printer identifies a horizontal offset of the printing medium from an expected location of the predetermined position proportional to the difference between the first distance and the predetermined distance.

Abstract: Techniques are disclosed for stitching images printed by a multi-head printer in a manner that is relatively insensitive to misregistration of the image segments. When a pair of overlapping print heads print a pair of adjacent image segments which meet in a stitching region, printing at each location in the stitching region is accomplished by both print heads with a weighting that depends on the location being printed within the stitching region. In one embodiment, for example, the output of each print head is weighted by a linear function of horizontal pixel position. Techniques are also disclosed for selecting screening patterns for use when stitching is performed with variable-dot printers. Such screening patterns are selected to minimize variations in density that may arise as the result of cross-web and/or down-web misregistration.

Abstract: Techniques are disclosed for correcting the exposure of a digital image. An exposure predictor may be generated based on a set of images for which ground truth data are known. After identifying an optimal set of features, the exposure of the digital image may be corrected by extracting values of the selected optimal features from the image, using the predictor to predict a desired exposure correction for the image, and correcting the exposure of the image by the predicted desired amount. Exposure correction is based on a model that relates intensity of light in the world to the RGB digits of the digital image. The model comprises a gamma function that models the response of a typical monitor and a S-shaped curve that compresses the large dynamic range of the world to the small dynamic range of the RGB digit space.

Abstract: Thermal history control is performed in a thermal printer in which a single thermal print head prints sequentially on multiple color-forming layers in a single pass. Each pixel-printing interval may be divided into segments, each of which may be used to print a different color. The manner in which the input energy to be provided to each print head element is selected may be varied for each of the segments. Different energy computation functions may be used to compute the energy to be provided to the print head in each of the segments based on the predicted print head element temperature at the beginning of the segment, the color to be printed, and the energy that was supplied when printing other colors during the time period between the beginning of the segment of the current pixel-printing interval and the end of the equivalent segment of the previous pixel-printing interval.

Abstract: The input energies provided to a print head of a thermal printer are adjusted based on the temperature of a platen in the thermal printer. The platen temperature may be measured by a sensor or predicted by a platen temperature model. Such a model may derive the predicted platen temperature from an observed temperature of a heat sink in the thermal printer. A thermal history control algorithm may use the platen temperature, whether actual or predicted, to compensate for the platen temperature by adjusting the input energies.

Abstract: Techniques are disclosed for stitching images printed by a multi-head printer in a manner that is relatively insensitive to misregistration of the image segments. When a pair of overlapping print heads print a pair of adjacent image segments which meet in a stitching region, printing at each location in the stitching region is accomplished by both print heads with a weighting that depends on the location being printed within the stitching region. In one embodiment, for example, the output of each print head is weighted by a linear function of horizontal pixel position. Techniques are also disclosed for selecting screening patterns for use when stitching is performed with variable-dot printers. Such screening patterns are selected to minimize variations in density that may arise as the result of cross-web and/or down-web misregistration.

Abstract: The input energies provided to a print head of a thermal printer are adjusted based on the temperature of a platen in the thermal printer. The platen temperature may be measured by a sensor or predicted by a platen temperature model. Such a model may derive the predicted platen temperature from an observed temperature of a heat sink in the thermal printer. A thermal history control algorithm may use the platen temperature, whether actual or predicted, to compensate for the platen temperature by adjusting the input energies.

Abstract: Techniques are disclosed for stitching images printed by a multi-head printer in a manner that is relatively insensitive to misregistration of the image segments. When a pair of overlapping print heads print a pair of adjacent image segments which meet in a stitching region, printing at each location in the stitching region is accomplished by both print heads with a weighting that depends on the location being printed within the stitching region. In one embodiment, for example, the output of each print head is weighted by a linear function of horizontal pixel position. Techniques are also disclosed for selecting screening patterns for use when stitching is performed with variable-dot printers. Such screening patterns are selected to minimize variations in density that may arise as the result of cross-web and/or down-web misregistration.

Abstract: Thermal history control is performed in a thermal printer in which a single thermal print head prints sequentially on multiple color-forming layers in a single pass. Each pixel-printing interval may be divided into segments, each of which may be used to print a different color. The manner in which the input energy to be provided to each print head element is selected may be varied for each of the segments. Different energy computation functions may be used to compute the energy to be provided to the print head in each of the segments based on the predicted print head element temperature at the beginning of the segment, the color to be printed, and the energy that was supplied when printing other colors during the time period between the beginning of the segment of the current pixel-printing interval and the end of the equivalent segment of the previous pixel-printing interval.

Abstract: Techniques are disclosed for stitching images printed by a multi-head printer in a manner that is relatively insensitive to misregistration of the image segments. When a pair of overlapping print heads print a pair of adjacent image segments which meet in a stitching region, printing at each location in the stitching region is accomplished by both print heads with a weighting that depends on the location being printed within the stitching region. In one embodiment, for example, the output of each print head is weighted by a linear function of horizontal pixel position. Techniques are also disclosed for selecting screening patterns for use when stitching is performed with variable-dot printers. Such screening patterns are selected to minimize variations in density that may arise as the result of cross-web and/or down-web misregistration.

Abstract: Techniques are disclosed for selectively dithering only a subset of a digital image. One or more ranges of digits are selected for dithering. Only those pixels having digits within the selected range(s) in the digital image are dithered. The image is printed after being selectively dithered. Digits may be selected for dithering if they have values within the range(s) of one or more non-monotonic regions of a printer transfer function. Dithering may be performed on the subset of the digital image by applying a nonlinear transformation is applied to the image and adding a dither pattern to the transformed image. The result is quantized, and the inverse of the nonlinear transformation is applied to the quantized image to produce a dithered image. The nonlinear transformation is constructed such that the effects of the dither pattern appear only in that subset of the image having digits in the selected range(s).

Abstract: Techniques are disclosed for correcting the exposure of a digital image. An exposure predictor may be generated based on a set of images for which ground truth data are known. After identifying an optimal set of features, the exposure of the digital image may be corrected by extracting values of the selected optimal features from the image, using the predictor to predict a desired exposure correction for the image, and correcting the exposure of the image by the predicted desired amount. Exposure correction is based on a model that relates intensity of light in the world to the RGB digits of the digital image. The model comprises a gamma function that models the response of a typical monitor and a S-shaped curve that compresses the large dynamic range of the world to the small dynamic range of the RGB digit space.

Abstract: Techniques are disclosed for correcting the exposure of a digital image. An exposure predictor may be generated based on a set of images for which ground truth data are known. After identifying an optimal set of features, the exposure of the digital image may be corrected by extracting values of the selected optimal features from the image, using the predictor to predict a desired exposure correction for the image, and correcting the exposure of the image by the predicted desired amount. Exposure correction is based on a model that relates intensity of light in the world to the RGB digits of the digital image. The model comprises a gamma function that models the response of a typical monitor and a S-shaped curve that compresses the large dynamic range of the world to the small dynamic range of the RGB digit space.