Moire Factors And Visibility In Scanned And Printed Halftone Images

Shu, Joseph; Yeh, Chia Lung

doi:10.1117/12.7977037

Cited by 14 publications

(7 citation statements)

References 1 publication

(1 reference statement)

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“…4,5 The common methods used to quantize a scanned halftone are error diffusion ͑ED͒, simple thresholding, rehalftoning, or descreening and rescreening. Quantization reduction via conventional ED typically produces fragmented dots ͓Fig.…”

Section: Introductionmentioning

confidence: 99%

Rank-ordered error diffusion: method and applications

Loce

2007

J. Electron. Imaging

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We present a specialized form of error diffusion (ED) that addresses certain long-standing problems associated with operating on images possessing halftone structure and other local highcontrast structures. For instance, image-quality defects often occur when rendering a scanned halftone image to printable form via quantization reduction. Rendering the scanned halftone via conventional ED produces fragmented dots, which can appear grainy and be unstable in printed density. Rendering by thresholding or rehalftoning often produces moiré, and descreening blurs the image. Another difficulty arises in printers that utilize a binary image path, where an image is rasterized directly to halftone form. In that form it is difficult to perform basic image processing operations such as applying a digital tone reproduction curve. Rank-order error diffusion (ROED) has been developed to address these problems. ROED utilizes brightness ranking of pixels within a diffusion mask to diffuse quantization error at a pixel. This approach results in an imagestructure-adaptive quantization with useful properties. We describe the basic methodology of ROED as well as several applications in processing halftone images. © 2007 SPIE and IS&T.

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Section: Introductionmentioning

confidence: 99%

Rank-ordered error diffusion: method and applications

Loce

2007

J. Electron. Imaging

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“…A. Steinbach and K. Y. Wong extended Huang's model to include the effects of scan aperture size and shape, and the reproduction printing process in the frequency domain [4]. J. Shu, R. Springer, and C. Yeh analyzed moire formation factors and derived a formula to manipulate these factors to minimize moire visibility [1]. J. Shu achieved moire elimination and tone correction using a local tonal compensation technique [5].…”

Section: Introductionmentioning

confidence: 99%

“…Much research has been done on the analysis and reduction of moire patterns by the various approaches as follows: (1) high frequency scanning (2) low pass filtering, (3) manipulation of the factors producing moire patterns, and (4) post-scan image processing algorithms [1][2][3][4]. A. Rosenfeld and A. Kak showed that moire patterns are caused by aliased frequencies produced when sampling images containing periodic structure [2].…”

Section: Introductionmentioning

confidence: 99%

<title>Adaptive hierarchical-filtering technique for high-quality magazine image reproduction</title>

et al. 2000

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This paper describes a novel adaptive-hierarchical-filtering technique to achieve high-quality magazine image reproduction on computer peripherals such as color copier, or scanner plus printer.Commercial magazine images are halfoned images. Unacceptable noises and moire distortion may result when halftone images are copied (i.e., scanned and printed). In this paper, we analyze moire patterns formation characterized by the following factors: Moire patterns formation depends on the following factors:(1) halftone screen frequency, how many lines per inch (i.e., lpi) (2) scan frequency, how many dot per inch, (dpi) (3) screen angle which is the screen orientation against the scan direction, (4) scanner aperture (i.e., scanner characteristics), (5) halftoning and printing mechanisms, (6) viewing conditions. Error diffusion tends to randomize the moire patterns, and cluster-dot or line screen show more moire distortion.We developed a set of variable-length low-pass filters that have a nice inheritance of canceling aliased low frequency components (moire distortion). High pass filtering is also applied to sharpen image edges. A hierarchical filter classifier was developed to determine that an edge is either a global true edge (for sharpening enhancement) or a local halftone's micro-structural edge (for LPF for moire reduction). Depending on the classifier, adaptive LPF is applied to achieve the smooth transition between sharp edges and smooth halftone regions. Thus, we achieves overall high-quality output images.Experimental results have been shown the effectiveness of the presented technique that works well on wide combinations of above-mentioned 6 factors for high-quality magazine image reproduction.

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“…To discover the solution of moiré noise reduction on various image applications, much research has been done by various approaches such as high frequency scanning, low pass filtering, manipulation of the factors producing moiré patterns, post-scan image processing algorithms [12][13][14][15], and etc. A. Rosenfeld and A. Kak showed that moiré patterns are caused by aliased frequencies when sampled images contain periodic structure [13].…”

Section: Introductionmentioning

confidence: 99%

“…Ville et al [19] proposed a nonlinear resampling method for moiré suppression. Shu et al [12] analyzed moiré formation factors and derived a formula to manipulate these factors to minimize moiré visibility. J. Shu achieved moiré elimination and tone correction using a local tonal compensation technique [20].…”

Section: Introductionmentioning

confidence: 99%

Adaptive-Hierarchical-Filtering Technique for High-Quality Magazine Image Reproduction

Lin

Shu

2005

J VLSI Sign Process Syst Sign Image Video Technol

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This paper proposes a novel adaptive filtering technique to achieve high-quality image enhancement when the image possesses the artifact of moiré pattern during the reproduction by different computer peripherals such as color copiers, or scanners plus printers.Commercial magazine images are halftoned images. Unacceptable noises and moiré distortion may occur when halftone images are copied (i.e., scanned and printed). In this paper, we analyze the formation of moiré patterns in both the frequency and spatial domain. Basically moiré noise often appears due to the aliased frequency when a halftone image is scanned. Based on the analysis of the scanned halftone image, we develop an adaptive filter to suppress the moiré artifacts and produce the high-quality image reproduction. The adaptive filter consists of modules of anti-aliased filter and image enhance filter: the anti-aliased filter is applied to cancel aliased low frequency components (moiré distortion); the image enhance filter is applied to sharpen image edges. It depends on the information provided by an image classification module to decide either the anti-aliased or image enhance module should be applied. The classification module is developed based on a set of pyramid images to determine an edge is either a global true edge (for sharpening enhancement) or a local halftone's micro-structural edge (for moiré reduction). Depending on the information from the classification module, the adaptive filter technique then applies the anti-aliased filter to the halftone micro-structured edge or the enhanced filter to the image global edge correctly and efficiently, and therefore both the moiré reduction and image enhancement can be achieved simultaneously. Experimental results show the outstanding effectiveness of the presented technique for high-quality magazine image reproduction.

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Moire Factors And Visibility In Scanned And Printed Halftone Images

Cited by 14 publications

References 1 publication

Rank-ordered error diffusion: method and applications

Rank-ordered error diffusion: method and applications

<title>Adaptive hierarchical-filtering technique for high-quality magazine image reproduction</title>

Adaptive-Hierarchical-Filtering Technique for High-Quality Magazine Image Reproduction

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