Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Faculty of Engineering | en_US |
| dc.contributor.advisor | Chan, Chris Y. H. (EIE) | - |
| dc.creator | Chen, Xiao | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/8002 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | - |
| dc.rights | All rights reserved | en_US |
| dc.title | Eliminating harmonics in tiled screens | en_US |
| dcterms.abstract | Halftoning is a process of transforming a continuous tone image to a bi-level image. Conventional frequency modulation halftoning algorithms are generally classified into three categories include: screening, error diffusion and iterative methods. Among them, screening is of the lowest realization complexity as it is carried out by thresholding the pixel values in an image with a pre-defined threshold matrix called screen. In general, in order to increase the flexibility, a small screen of fixed size, which is referred to as tile screen, is developed in advance. Whenever necessary, a screen of desirable size is constructed on line to halftone a given image by tiling the developed tile screens.Conventional tiling methods can introduce blocking artifacts to a screening output if the spatial inter-correlation among adjacent tile screens in a constructed screen is not taken into account when developing the tile screens. These blocking artifacts appear as some abrupt transition across the boundary of two blocks in a screening output. Conventional tiling methods can also introduce some harmonic distortion to the screening output when the constructed screen is periodic. This work addresses these issues and proposes some solutions to remove the blocking artifacts and the harmonic distortion that are commonly found in the outputs of conventional screening algorithms. | en_US |
| dcterms.extent | x, 100 leaves : illustrations ; 30 cm | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2015 | en_US |
| dcterms.educationalLevel | All Master | en_US |
| dcterms.educationalLevel | M.Sc. | en_US |
| dcterms.LCSH | Photoengraving -- Halftone process. | en_US |
| dcterms.LCSH | Image processing -- Digital techniques. | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | restricted access | en_US |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b28110559.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 3.57 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/8002