Method and apparatus for printer/scanner calibration
First Claim
1. A method for calibrating a printer and/or a scanner so that information can be printed at a desired location with respect to a sheet, the method comprising:
- storing a first set of markings as a first image in digital form;
printing, using a printer to be calibrated, the first image on a sheet to form a printed sheet;
scanning the printed sheet to generate a second image stored in digital form;
comparing the first image and the second image, or an image derived from the second image, to determine a first transformation which maps the first set of markings in the second image, or the image derived from the second image, onto the first set of markings on the first image;
storing parameters of the first transformation for subsequent use by applying the first transformation to information to be printed at the desired location;
storing a second set of markings as a third image in digital form;
printing the first set of markings on a sheet on which the second set of markings are printed at a known location to form a composite printed sheet;
comparing the second image and the third image to determine a second transformation which maps the second set of markings in the second image onto the second set of markings on the third image;
applying the second transformation to the second image;
subtracting the third image from the second image to generate a fourth image;
comparing the first image and the fourth image to determine the first transformation.
1 Assignment
0 Petitions
Accused Products
Abstract
A method is described for calibrating a printer and/or a scanner so that information can be printed at a desired location with respect to a sheet, the method comprising: storing a first set of markings as a first image in digital form; printing, using a printer to be calibrated, the first image on a sheet to form a printed sheet; scanning the printed sheet to generate a second image stored in digital form; comparing the first image and the second image, or an image derived from the second image, to determine a first transformation which maps the first set of markings in the second image, or the image derived from the second image, onto the first set of markings on the first image; storing parameters of the first transformation for subsequent use by applying the first transformation to information to be printed at the desired location. Using this method the bias transformations associated with a printer and/or a scanner can be accurately measured and stored for future use in printing. The method finds particular application in a system for enabling the filling in of preprinted forms.
50 Citations
9 Claims
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1. A method for calibrating a printer and/or a scanner so that information can be printed at a desired location with respect to a sheet, the method comprising:
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storing a first set of markings as a first image in digital form; printing, using a printer to be calibrated, the first image on a sheet to form a printed sheet; scanning the printed sheet to generate a second image stored in digital form; comparing the first image and the second image, or an image derived from the second image, to determine a first transformation which maps the first set of markings in the second image, or the image derived from the second image, onto the first set of markings on the first image; storing parameters of the first transformation for subsequent use by applying the first transformation to information to be printed at the desired location; storing a second set of markings as a third image in digital form; printing the first set of markings on a sheet on which the second set of markings are printed at a known location to form a composite printed sheet; comparing the second image and the third image to determine a second transformation which maps the second set of markings in the second image onto the second set of markings on the third image; applying the second transformation to the second image; subtracting the third image from the second image to generate a fourth image; comparing the first image and the fourth image to determine the first transformation. - View Dependent Claims (2, 3, 4)
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5. A data processing system for calibration of a printer, said system comprising:
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means for storing a first set of markings as a first image in digital form; means for printing on said printer to be calibrated the first image on a sheet to form a printed sheet; means for scanning the printed sheet to generate a second image stored in digital form; means for comparing the first image and the second image, or an image derived from the second image, to determine a first transformation which maps the first set of markings in the second image, or the image derived from the second image, onto the first set of markings on the first image; means for storing parameters of the first transformation for subsequent use by applying the first transformation to information to be printed at the desired location; means for storing a second set of markings as a third image in digital form; means for printing the first set of markings on a sheet on which the second set of markings are printed at a known location to form a composite printed sheet; means for comparing the second image and the third image to determine a second transformation which maps the second set of markings in the second image onto the second set of markings on the third image; means for applying the second transformation to the second image; means for subtracting the third image from the second image to generate a fourth image; means for comparing the first image and the fourth image to determine the first transformation. - View Dependent Claims (6, 7, 8, 9)
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Specification