The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 09, 2008
Filed:
Jun. 04, 2004
Ying-wei Lin, Penfield, NY (US);
Shen-ge Wang, Fairport, NY (US);
Beilei Xu, Penfield, NY (US);
Xerox Corporation, Norwalk, CT (US);
Abstract
A system and method for classifying an image block of a printed image into contone, halftone, or error diffusion classes, includes scanning the printed image; selecting an n by n block of pixels from the scanned image in a luminance channel; calculating an array of DCT coefficients of the pixel block, wherein the calculated DCT coefficients are representative of spatial frequency and spatial orientation of the pixel block; comparing the array of DCT coefficients with an array of predetermined values, wherein the array of predetermined values are indicative of contone, halftone and error diffusion classes; and determining the image classification of the pixel block based on the comparison of the DCT coefficients with the array of predetermined values. If the image is determined to be halftone, then the method further evaluates the DCT coefficients to determine the frequency of the halftone screen.