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:
Jul. 27, 1993
Filed:
Jan. 31, 1991
Joel D Gengler, Boulder, CO (US);
Brad D Reak, Loveland, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A digital image blending/comparison circuit which lets a user draw several planar images and then sum them together with a scalable 'blend' function or subtract them and display the difference image. An image frame buffer is subdivided to store multiple images provided by the user, and the resulting multiple images are combined as a single image within a display window on a pixel by pixel basis during a blending mode or subtracted within a display window on a pixel by pixel basis in a comparison mode. During the blending mode, the invention sums the pixel color data on a per-pixel basis, where the pixel data is scaled as a separate operation on color map entries. However, during the comparison mode, the invention subtracts the pixel color data on a per-pixel basis and scales the difference image signal so that it is perceptible on the display. Control information is fed to the circuit of the invention on pixel boundaries from the frame buffer, and the circuit of the invention responds to combine or compare the images in accordance with the preferences of the user. As a result, each display pixel may selectively show a single image, a combined image or a difference image from the associated window. The invention also allows for separate processing of data within each window by defining each pixel with respect to its window boundaries.