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. 11, 2003
Filed:
Apr. 07, 1999
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
When maximum density of an output image is lowered by a gamma correction, the number of tones is reduced and the tonality of the output image declines. In order to solve this problem, a pattern generator ( ) is caused to generate a toned pattern and the gain of a D/A converter of a PWM circuit ( ) is controlled so as to output a test pattern having a density ranging from maximum pulse width Pff(50%) to maximum pulse width Pff(100%) for each color component (step S ). Image information that has been read (step S ) from the test pattern is converted to density information (step S ), and Pff is set (step S ) from the relationship between Pff and image density based upon coordinate information provided by the test pattern.