• Journal of the Korean Graphic Arts Communication Society
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• v.21 no.1
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• pp.1-10
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• 2003

Printing ink is faced various shear stress situation until it transfer to the printed substrate through the press. And in each shear stress condition the ink is needed to keep the appropriate viscosity according to the condition. The change of printing ink viscosity has been explained by well-known through the viscosity profile curve. But actually, the quality of printed paper depends on the ink behavior after transfer the substrates. Like this, to look into the behaviour of the ink on the printed substrate, it is needed the experiment of the ink structure recovering by rheology study. In this study, by controling the $CaCO_3$ content in the ink, after investigating the effect of the ink's structure recovery of the pigment concentration, we intend to predict the printing quality of the ink behvior on the substrate depending on pigment content.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1997.11a
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• pp.146-151
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• 1997

Recntly many devics print electronic images in a variety of ways. But the reproduced color, gamut mappung method and expanded nonlinear quantization are proposed. The color gamut mapping uses saturation mapping of HSI color space. Dithering operation for printing uses expanded nonlinear quantization which considers overlapping phenomena of neighboring printing dots. So the printed image is similar to the image of monitor and can produce high quality image in the low bit color devices.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.270-279
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• 1997

The conversion of printed maps into computerized databases is an enormous task. Thus the automation of the conversion process is essential. Efficient computer representation of printed maps and line drawings depends on codes assigned to characters, symbols, and vector representation of the graphics. In many cases, maps are constructed in a number of layers, where each layer is printed in a distinct color, and it represents a subset of the map information. In order to properly represent the character layer from color map images, an interactive clustering and character extraction technique is proposed. Character is usually separated from graphics by extracting and classifying connected components in the image. But this procedure fails, when characters touch or overlap lines-something that occurs often in land register maps. By vectorizing line segments, the touched characters and numbers are extracted. The algorithm proposed in this paper is intended to contribute towards the solution of the color image clustering and touched character problem.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.327-339
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• 2004

In this paper, we propose a new watermark algorithm for halftone images using iterative error minimizing method. In the proposed method, watermark bits are hidden at pseudo-random locations within a halftone image. To remove the distortions due to the inserted watermark bits and increase the invisibility of watermark, an iterative error minimizing technique is used. We define the halftoning error is defined as the difference between the original grayscale image and HVS-filtered printed halftone image. Then we iteratively find the pixel pattern with minimum halftoning error and displace the original pixel pattern with it. In order to be robust to geometrical modification like cropping or rotation, we insert the same watermark periodically into halftone images. Experiments using printed and scanned images show that the proposed method is a robust method to the geometrical modification and to hide the large amount of data within a halftone image without noticeable distortion.

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.26-31
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• 2012

We have proposed a metamaterial lens that enables sub-wavelength focusing, which is shorter than an operating wavelength. Our lens is a two dimensional array of a unit cell consisting of a metallic dual-plate printed on a dielectric substrate. The unique dual-plate structure provides negativeness both in permittivity and permeability, with no help from conventional additional structures, which are normally printed on the opposite of metallic patterns. Therefore, we can focus a source (or an image) in a tiny distance shorter than the free space wavelength (${\lambda}$) at the frequencies of interest. Furthermore, since the proposed geometry does not need separate supplementary structures to acquire negative permittivity or permeability, our lens is much simpler than conventional metamaterial lenses, which is a strong point in practical applications. We have validated sub-wavelength focusing ability in a 6 GHz frequency band through an experiment of near field scanning, which provided the width of about 0.19 ${\lambda}$ at a half maximum of a peak value of an measured image. The width of the focused image through the lens is more than 4 times shorter than that without the lens, which confirms the validity of our design approach.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.2
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• pp.31-44
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• 2010

Ever since the introduction of offset lithography, an operator have looked for ways to improve the process by reducing need for dampening solution. Lithography like off-set printing is processed using the repellent properties between water and oil, so all inks for lithography printing must work with dampening solution. The dampening solution may cause the emulsification of ink by the printing pressure in the printing nip. Emulsified ink changed viscosity, tack and causes problems such as bad transfer, uniform density and printed mottle. For a high quality web printing, we studied the effect of emulsified heat-set web inks on the printability, such as amount of ink transfer, printed density and uniformity. For this study, we were carried out by using IGT printability tester C1. For determination of ink properties using the spread meter and Thwing Albert Ink-o-meter, and using the densitometer and image analysis for printed quality determination. The experimental results of this study, we look forward to can be used as the basis for improve of the web print quality.

• Smart Media Journal
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• v.1 no.4
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• pp.59-71
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• 2012

Since mobile phones are used as common communication devices, their applications are increasingly important to human's life. Using smart-phones camera to collect daily life environment's information is one of targets for many applications such as text recognition, object recognition or context awareness. Studies have been conducted to provide important information through the recognition of texts, which are artificially or naturally included in images and movies acquired from mobile phones. In this study, a character segmentation method that improves character-recognition accuracy in images obtained from mobile phone cameras is proposed. The proposed method first classifies texts in a given image to printed letters and handwritten letters since segmentation approaches for them are different. For printed letters, rough segmentation process is conducted, then the segmented regions are integrated, deleted, and re-segmented. Segmentation for the handwritten letters is performed after skews are corrected and the characters are classified by integrating them. The experimental result shows our method achieves a successful performance for both printed and handwritten letters as 95.9% and 84.7%, respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.36.2-36.2
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• 2009

In this work, the high power CW Nd:YAG laser has been used for thermal treatment of inkjet printed Ag films-involving eliminating organic additives (dispersant, binder, and organic solvent) of Ag ink and annealing Ag nanoparticles. By optimizing laser parameters, such as laser power and defocusing value, the laser energy can totally be converted to heat energy, which is used to thermal treatment of inkjet printed Ag films. This results in controlling the microstructures and the resistivity of films. We investigated the thermal diffusion mechanisms during laser annealing and the resulting microstructures. The impact of high power laser annealing on microstructures and electrical characteristic of inkjet printed Ag films is compared to those of the films annealed by a conventional furnace annealing. Focused ion beam (FIB) channeling image shows that the laser annealed Ag films have large columnar grains and dense structure (void free), while furnace annealed films have tiny grains and exhibit void formation. Due to these microstructural characteristics of laser annealed films, it has better electrical property (low resistivity) compared to furnace annealed samples.

• The Journal of Korean Institute of Information Technology
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• v.15 no.12
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• pp.165-171
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• 2017

This paper proposes a method of support-generation using morphological image processing instead of geometric calculations. The geometric computational cost is dependent on the shape, but our method is independent on the shape. For obtaining the external support area for extrusion shape, we represents morphological operations between two sliced layer images and shows results of each operation stages. Internal support area is evaluated from erosion and opening operations with the sliced-layer image. In these support areas, the supporter image is generated using the designed support structures. Also, we made a DLP printer and the STL model included supporter-structure is printed by the DLP printer. We confirmed the necessity of support-generation method with the support structures individually dependent on materials by looking at the printed results.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.2
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• pp.1-13
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• 2008

Printed mottle of coated paper is one of the most common phenomenon and the most difficult problem in offset printing. Offset printing is processed mainly processed by the attractive properties between water and oil, so all inks for off-printing must work with dampening solution(water). It may cause the emulsion on the printing nip from the printing pressure. This study aimed to investigate the effect of emulsified inks on print mottle from emulsified cyan ink by force with each different IP A contents. We measured the print mottle by densitometer and image analysis method. The emulsified inks also give effect to now properties of inks and it caused more ink transfer rate, however, it caused low density of inks. Moreover the emulsified inks were spreaded to around of dots and cause the thinning density on the non-printing area like print mottle. The results showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. So we could find out the obvious effect of emulsified inks to print mottle.