Multi-color and artistic dithering

We present a method for hiding images in synthetic videos and reveal them by temporal averaging. The main challenge is to develop a visual masking method that hides the input image both spatially and temporally. Our masking approach consists of temporal and spatial pixel by pixel variations of the frequency band coefficients representing the image to be hidden. These variations ensure that the target image remains invisible both in the spatial and the temporal domains. In addition, by applying a temporal masking function derived from a dither matrix, we allow the video to carry a visible message that is different from the hidden image. The image hidden in the video can be revealed by software averaging, or with a camera, by long exposure photography. The presented work may find applications in the secure transmission of digital information.

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“…We thus propose to replace the spatial noise with meaningful patterns. For this purpose, we make use of artistic dither matrices [37].…”

Section: Temporal Dither Masking Functionmentioning

confidence: 99%

“…Artistic dithering enables ordering these threshold levels so that for most levels turned-on pixels depict a meaningful shape [37]. We adapt artistic dithering to provide visual meaning to tempocode videos.…”

Section: Temporal Dither Masking Functionmentioning

confidence: 99%

Revealing information by averaging

2017

Self Cite

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“…This is also true for artistic screening systems which use characters for shading [Ostromoukhov and Hersh 1999]. Combining upper and lowercase characters disturbs shading for the following reasons:…”

Section: Shading Modementioning

confidence: 99%

Improving readability of contextualized text explanations

Chigona¹,

Strothotte²

2003

Proceedings of the 2nd International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa

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DUAL-USE OF IMAGE SPACE (DUIS) is an interactive techniquefor presenting text corresponding to images within the image space. From a technical point of view, the pixels in the image space are used both as text which can be read as well as for shading. This approach raises a number of interesting new readability problems: First, in order to simulate shading, the weight and the width of the character glyphs are manipulated. We have noted that readers find reading text with weight and width variations not only difficult but also irritating. Second, the shape of the silhouettes of the objects, by their irregular nature, are not ideal for text layout.In this paper we present techniques for addressing the DUIS readability problems. The techniques are divided into three categories as follows: First, shading and reading functionalities have been separated by creating two text presentation modes, shading mode and reading mode. In reading mode, it is no longer necessary to vary the weight and width of the character glyphs. Second, we have introduced the concept of multiple column presentation to address the problems of interruptions in reading. Finally, distortions of the objects are also used to improve readability.

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“…[8][9][10][11][12][13][14][15][16] Usually, these works divide the ink set into smaller subsets and make the color separation simpler. When there are multiple choices between different ink subsets, they might select the solution that optimizes one or more print attributes.…”

Section: Introductionmentioning

confidence: 99%

Color Reproduction of Metallic-Ink Images

Babaei¹,

Hersch²

2016

jist

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Abstract. We study the color reproduction of full-color metallic-ink images. Full-color metallic-ink images are prints whose contributing colorants are exclusively made of colored metallic inks. Due to the presence of metallic particles, metallic inks show a metal-like luster. These particles are opaque and hide the underlying ink or substrate. In order to obtain predictable halftone colors, we need a juxtaposed halftoning method to create halftone dots of different colors side by side without overlapping. Juxtaposed halftoning invalidates many assumptions generally made for the color-reproduction workflow. For printing metallic-ink images, one needs a color-separation system creating surface coverages for the eight metallic inks that correspond to the eight Neugebauer primaries. For this purpose, we introduce a simple and fast method for N-color separation that relies either on Demichel's or on a variant of Kueppers' ink-to-colorant separations. Thanks to a unique set of ink-to-colorant formulas, pseudo-CMY ink values are separated into amounts of printable colorants. We also describe color-separation procedures that are able to optimize different properties of the resulting metallic-ink images. INTRODUCTIONA common element present in all printing applications is the color-reproduction workflow. A color-reproduction workflow converts an input image into the printer's command language. 1 Most existing reproduction workflows follow the steps shown in Figure 1. Briefly, input colors are first converted from a source color space, such as sRGB, into a device-independent color space such as CIELAB. 2 By performing gamut mapping, 3 the input colors are mapped into the colors of the usually narrower print gamut. Then, the color separation is carried out by converting the gamut-mapped printable colors into amounts of printer inks. The separated ink layers are then halftoned and printed.We can use a spectral prediction model for color separation and gamut mapping. The forward prediction model expresses the forward characterization. It determines the printer's color response to input control values, e.g. the amount of inks to be printed. By varying the amount of inks in the forward model, we can determine the color gamut of a printer. The spectral prediction model is also required in inverse mode for the color separation in order to deduce the amounts of inks that are needed to print a specific color.

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Multi-color and artistic dithering

Cited by 44 publications

References 10 publications

Revealing information by averaging

Revealing information by averaging

Improving readability of contextualized text explanations

Color Reproduction of Metallic-Ink Images

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