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:
Jan. 23, 2001
Filed:
Mar. 24, 1998
Qian Lin, Santa Clara, CA (US);
Brent M. Bradburn, Boise, ID (US);
Brian E. Hoffmann, Ranica BG, IT;
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An Adaptive Image Resolution Enhancement Technology (IRET) process and apparatus is described to improve halftone imaging by changing ordered halftone screen resolution according to the content of the image and managing these changes based on image content. The Adaptive IRET halftoning technique maximizes the artifact reducing properties of coarser ordered screens, while minimizing the loss of rendered detail in image areas having high spatial frequency. IRET may utilize a mixture of any ordered halftone screen (e.g. clustered-dot dither, line screen, etc.) to generate halftone dots with a number of levels, and any dispersed halftone screen to generate additional levels for the ordered halftone dots. For some printing technologies, it is preferable to minimize printing artifacts by generating coarser halftone screens, rather than finer halftone screens. Coarser screening, however, means that details in the image, text, and line art will not be rendered well. Adaptive IRET uses an activity index to change its ordered halftone screen resolution according to the content of the image. To render a page with a mixture of text, line art, area fill, and photograph, it is preferable to render the “busy” areas, such as text, line art, and edge regions in a photograph, with a higher resolution screen. On the other hand, smooth areas, such as area fill and non-edge regions in a photograph, are better rendered with a lower resolution screen.