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:
May. 04, 2004
Filed:
Feb. 05, 2001
Hiroyuki Shibaki, Tokyo-to, JP;
Hiromi Okubo, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An apparatus and method to convert input image data having a first multivalue to image data having a second multivalue which is less than the first multivalue by using a multi error diffusion technique. An image processing apparatus includes a threshold generating device for generating a plurality of variable thresholds at least based on a characteristic of a target pixel data, wherein a number of the variable thresholds is less than a number of the second multivalue by one. A quantization device is provided to quantize the input image data of the target pixel into the image data having the second multivalue based on the variable thresholds. The variable thresholds are varied in a manner such that predetermined quantized data quantized by the quantization device does not create noticeable banding substantially in a middle density range and does not create noticeable dropout substantially in a high density range.