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:
Feb. 09, 1999
Filed:
Mar. 14, 1996
Munib A Wober, Haverhill, MA (US);
Ibrahim Hajjahmad, Sommerville, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A method for adjusting the luminance IM.sub.HI of pixels in a high resolution image includes first forming a low resolution image of the original by grouping pixels into superpixels such as 8.times.8 blocks. A low resolution luminance correction value .delta..sub.LO is determined for each superpixel by comparing the luminance of the superpixel to both a predetermined darkness threshold T.sub.D and a predetermined brightness threshold T.sub.B. The low resolution luminance correction value .delta..sub.LO is modified to yield .delta.'.sub.LO for each superpixel by forming islands of the superpixels and smoothing .delta..sub.LO between superpixels within each island. Finally, a high resolution luminance correction value .delta..sub.HI is calculated for each pixel of the original high resolution image by comparing the luminance IM.sub.HI of each pixel to both T.sub.D and T.sub.B, keeping in mind that .delta..sub.HI is generated through a series of mathematical computations as a function of both the pixel luminance IM.sub.HI and the low resolution luminance correction value .delta..sub.LO. Each pixel of the original image is adjusted by the corresponding high resolution luminance correction value .delta..sub.HI and a luminance adjusted image is produced.