The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform

J.p. Allebach - One of the best experts on this subject based on the ideXlab platform.

  • Joint halftoning and watermarking
    IEEE Transactions on Signal Processing, 2003
    Co-Authors: D. Kacker, J.p. Allebach
    Abstract:

    A framework to jointly halfTone and watermark a grayscale Images is presented. The framework needs the definition of three components: a human visual system (HVS)-based error metric between the Continuous-Tone Image and a halfTone, a watermarking scheme with a corresponding watermark detection measure, and a search strategy to traverse the space of halfTones. We employ the HVS-based error metric used in the direct binary search (DBS) halftoning algorithm, and we use a block-based spread spectrum watermarking scheme and the toggle and swap search strategy of DBS. The halfTone is printed on a desktop printer and scanned using a flatbed scanner. The watermark is detected from the scanned Image and a number of post-processed versions of the scanned Image, including one restored in Adobe PhotoShop. The results show that the watermark is extremely resilient to printing, scanning, and post-processing; for a given baseline Image quality, joint optimization is better than watermarking and halftoning independently. For this particular algorithm, the original Continuous-Tone Image is required to detect the watermark.

  • A dual interpretation for direct binary search and its implications for Tone reproduction and texture quality
    IEEE Transactions on Image Processing, 2000
    Co-Authors: D.j. Lieberman, J.p. Allebach
    Abstract:

    The direct binary search (DBS) algorithm employs a search heuristic to minimize the mean-squared perceptually filtered error between the halfTone and Continuous-Tone original Images. Based on an efficient method for evaluating the effect on the mean squared error of trial changes to the halfTone Image, we show that DBS also minimizes in a pointwise sense the absolute error under the same visual model, but at twice the viewing distance associated with the mean-squared error metric. This dual interpretation sheds light on the convergence properties of the algorithm, and clearly explains the Tone bias that has long been observed with halftoning algorithms of this type. It also demonstrates how Tone bias and texture quality are linked via the scale parameter, the product of printer resolution and viewing distance. Finally, we show how the Tone bias can be eliminated by Tone-correcting the Continuous-Tone Image prior to halftoning it.

Jan P. Allebach - One of the best experts on this subject based on the ideXlab platform.

  • Joint design of plane-dependent FM screens sets using DBS algorithm
    Color and Imaging Conference, 2019
    Co-Authors: Yi Yang, Jan P. Allebach
    Abstract:

    Color Halftoning is a technique for generating a halfTone Image by using a limited number of colorants to simulate a Continuous-Tone Image as perceived by a human viewer. This paper describes an algorithm to jointly design three screens for Cyan, Magenta and Yellow colorants using the Direct Binary Search algorithm. The results show that high-quality color halfTone Images can be obtained using the screens sets, and the computational complexity will be greatly reduced.

  • block interlaced pinwheel error diffusion
    Journal of Electronic Imaging, 2005
    Co-Authors: Pingshan Li, Jan P. Allebach
    Abstract:

    Error diffusion is a popular halftoning algorithm that in its most widely used form, is inherently serial. As a serial algorithm, error diffusion offers limited opportunity for large-scale parallelism. In some implementations, it may also result in excessive bus traffic between the on-chip processor and the off-chip memory used to store the modified Continuous-Tone Image and the halfTone Image. We introduce a new error diffusion algorithm in which the Image is processed in two groups of interlaced blocks. Within each group, the blocks may be processed entirely independently. In the first group, the error diffusion proceeds along an outward spiral from the center of the block. Errors along the boundaries of blocks in the first group are diffused into neighboring blocks in the second group, within which the error diffusion spirals inward. A Tone-dependent error diffusion training framework is used to eliminate artifacts associated with the spiral scan paths. We demonstrate Image quality that is close to that achieved by conventional line-by-line error diffusion.

  • Color Imaging: Processing, Hardcopy, and Applications - Compressible error diffusion
    electronic imaging, 2003
    Co-Authors: Jan P. Allebach
    Abstract:

    This paper presents a combined halftoning and compression approach, which achieves high quality halfTones and compression ratios comparable to those of JBIG with much simpler encoding and decoding schemes. In the proposed algorithm, we halfTone the input Continuous-Tone Image with constraints in a controlled manner, so that we can decrease the entropy of the resulting halfTones while maintaining a high level of visual Image quality.

  • New results on reconstruction of Continuous-Tone from halfTone
    [Proceedings] ICASSP-92: 1992 IEEE International Conference on Acoustics Speech and Signal Processing, 1992
    Co-Authors: M. Analoui, Jan P. Allebach
    Abstract:

    Two iterative methods are used to reconstruct a Continuous-Tone Image from its halfTone: successive approximation and projection onto convex sets. The halfTone Image is assumed to be generated by thresholding with an unknown screen function which is estimated from the halfTone Image in the first stage of the reconstruction process. The screen function is an integral part of both iterative reconstruction methods. The other key element is a constraint on the bandwidth of the reconstructed Image. Relaxing this constraint during the course of the iterations not only reduces the RMS error after each iteration but also achieves a relatively sharp full-band reconstruction at the end.

D. Kacker - One of the best experts on this subject based on the ideXlab platform.

  • Joint halftoning and watermarking
    IEEE Transactions on Signal Processing, 2003
    Co-Authors: D. Kacker, J.p. Allebach
    Abstract:

    A framework to jointly halfTone and watermark a grayscale Images is presented. The framework needs the definition of three components: a human visual system (HVS)-based error metric between the Continuous-Tone Image and a halfTone, a watermarking scheme with a corresponding watermark detection measure, and a search strategy to traverse the space of halfTones. We employ the HVS-based error metric used in the direct binary search (DBS) halftoning algorithm, and we use a block-based spread spectrum watermarking scheme and the toggle and swap search strategy of DBS. The halfTone is printed on a desktop printer and scanned using a flatbed scanner. The watermark is detected from the scanned Image and a number of post-processed versions of the scanned Image, including one restored in Adobe PhotoShop. The results show that the watermark is extremely resilient to printing, scanning, and post-processing; for a given baseline Image quality, joint optimization is better than watermarking and halftoning independently. For this particular algorithm, the original Continuous-Tone Image is required to detect the watermark.

Toshiharu Sugie - One of the best experts on this subject based on the ideXlab platform.

  • Inverse halftoning using super‐resolution Image processing
    Ieej Transactions on Electrical and Electronic Engineering, 2011
    Co-Authors: Yuki Minami, Shun-ichi Azuma, Toshiharu Sugie
    Abstract:

    This paper focuses on the inverse halftoning problem, that is, the problem of reconstructing Continuous-Tone Images from halfTone Images of white and black pixels. In general, the problem does not have a unique solution, since halftoning is a many-to-one map from Continuous-Tone Images to binary ones. To this problem, we provide a simple and useful inverse halftoning method, composed of two steps. The first step is to generate several grayscale Images from the original halfTone Image and low-pass filters. The next step is to reconstruct a Continuous-Tone Image from the multiple grayscale Images by using super-resolution Image processing. This method allows us to obtain good Continuous-Tone Images which are comparable to the results of the existing methods. The validity of the proposed method is demonstrated by several experiments. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

  • An inverse halftoning algorithm based on super-resolution Image reconstruction
    Proceedings of SICE Annual Conference 2010, 2010
    Co-Authors: Yuki Minami, Shun-ichi Azuma, Toshiharu Sugie
    Abstract:

    Inverse halftoning is to reconstruct Continuous-Tone Images from binary ones composed of white and black pixels. This paper presents a simple and useful inverse halftoning method, which is a two-step algorithm. The first step is to generate several grayscale Images from the original halfTone Image and lowpass filters. The next step is to reconstruct a Continuous-Tone Image from the multiple grayscale Images by using the super-resolution Image reconstruction. The effectiveness of the proposed method is demonstrated by several experiments.

Enis A. Cetin - One of the best experts on this subject based on the ideXlab platform.

  • Restoration of error-diffused Images using POCS
    1999 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258), 1999
    Co-Authors: Gozde Bozkurt, Enis A. Cetin
    Abstract:

    Halftoning is a process that deliberately injects noise into the original Image in order to obtain visually pleasing output Images with a smaller number of bits per pixel for displaying or printing purposes. In this paper, a novel inverse halftoning method is proposed to restore a Continuous Tone Image from the given halfTone Image. A set theoretic formulation is used where three sets are defined using the prior information about the problem. A new space domain projection is introduced assuming the halftoning is performed with error diffusion, and the error diffusion filter kernel is known. The space domain, frequency domain, and space-scale domain projections are used alternately to obtain a feasible solution for the inverse halftoning problem which does not have a unique solution.

  • Set theoretic inverse halftoning method for grayscale and color Images
    Visual Communications and Image Processing '99, 1998
    Co-Authors: Gozde Bozkurt, Enis A. Cetin
    Abstract:

    Inverse halftoning is the problem of recovering a Continuous- Tone Image from a given halfToned Image. In this paper, a new inverse halftoning method which uses a set theoretic formulation is introduced. The new method exploits the prior information at hand, and uses space-domain projections, frequency-domain projections, and space-scale domain projections to obtain a feasible reconstruction of the Continuous-Tone Image. The proposed method is also extended for the inverse halftoning of color error-diffused Images.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.