نتایج جستجو برای: halftone
تعداد نتایج: 479 فیلتر نتایج به سال:
The error diffusion method generates worm artifacts, and weakens the edge of the halftone image when the continuous gray scale image is reproduced by a binary image. First, to enhance the edges, we propose the edge-enhancing filter by considering the quantization error information and gradient of the neighboring pixels. Furthermore, to remove worm artifacts often appearing in a halftone image, ...
In many printer and publishing applications, it is desirable to embed data in halftone images for copyright control and authentication purposes. While intentional attacks on printed matters may not be likely, unintentional attacks such as cropping and distortion due to dirt or human writing/marking are likely. In this paper, we proposed a novel halftone image watermarking method to embed a robu...
We present a multiresolutional algorithm that segments a compound document and uses the results of the segmentation for document enhancement in copier applications. The document is initially segmented into halftone and non-halftone areas. Based on this segmentation the location of the edges due to text, graphics, and images (and not due to halftone dots) are detected on halftone as well as on n...
This paper challenges the problem of estimating the original red–green–blue (RGB) image from a black-and-white (B&W) halftone image with homogeneously distributed dot patterns. To achieve this goal, training RGB images are converted into color-embedded gray images using the conventional reversible color to gray conversion method, and then converted into halftone images using error diffusion in ...
A new inverse halftoning algorithm based on reversible data hiding techniques for halftone images is proposed in this paper. The proposed scheme has the advantages of two commonly used methods, the lookup table (LUT) and Gaussian filtering methods. We embed a part of important LUT templates into a halftone image and restore the lossless image after these templates have been extracted. Then a hy...
A framework for clustered-dot color halftone watermarking is considered, wherein watermark patterns are embedded in individual colorant halftones prior to printing and embedded watermarks are detected from scans of the printed images after obtaining estimates of the individual halftone separations. The principal challenge in this methodology arises in the watermark detection phase. Typical thre...
The objective of this work is to reconstruct high quality gray-level images from bilevel halftone images. We develop optimal inverse halftoning methods for several commonly used halftone techniques, which include dispersed-dot ordered dither, clustered-dot ordered dither, and error diffusion. At first, the least-mean-square (LMS) adaptive filtering algorithm is applied in the training of invers...
In this paper, a novel wavelet-based approach to recover continuous tone images from halftone images is presented. Wavelet decomposition of the halftone image facilitates a series of spatial and frequency selective processing to preserve most of the original image contents while eliminating the halftone noise. Furthermore, optional non-linear ltering can be applied as a post-processing stage to...
In this paper, we propose a new halftone watermarking method named Data Hiding by Dual Conjugate Error Diffusion (DHDCED) based on Data Hiding by Conjugate Error Diffusion (DHCED). Unlike DHCED, The proposed method will embed a binary secret pattern into two or more error diffused halftone images by modifying each of them. When the two halftone images are overlaid, the secret pattern will be re...
A framework for clustered-dot color halftone watermarking is proposed. Watermark patterns are embedded in the color halftone on per-separation basis. For typical CMYK printing systems, common desktop RGB color scanners are unable to provide the individual colorant halftone separations, which confounds per-separation detection methods. Not only does the K colorant consistently appear in the scan...
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