Apparatus and method for forming an image by processing input image data while suppressing banding and dropout
US6731817B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2001 |
| Grant date | May 4, 2004 |
| Priority date | — |
| Expiry date | Nov 14, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.