• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.191-194
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• 2012

Rendering maps is an essential feature of the user interface component of a location based service (LBS) system. However, a developer may not too much worry about implementing the rendering maps part of his or her system because there are quite a few publicly available libraries that provide all kinds of functions of manipulating maps. Google Maps, Yahoo Map, Naver Map, Daum Map, and so on are example sites that provide those libraries. Rendering drawings is to indoor LBS as rendering maps is to LBS. However, there is no such thing as Google Maps that provides libraries for rendering drawings. This paper introduces a few web services and a library that is useful in developing user interfaces of indoor LBS systems.

• Journal of Korea Multimedia Society
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• v.14 no.8
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• pp.1082-1093
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• 2011

Traditional rendering of cartoon character cannot revive the feeling of concept drawings properly. In this paper, we propose capture technology to get toon shading model from the concept drawings and with this technique, we provide a new novel system to render 3D cartoon character. Benefits of this system is to cartoonize the 3D character according to saliency to emphasize the form of 3D character and further support the sketch-based user interface for artists to edit shading by post-production. For this, we generate texture automatically by RGB color sorting algorithm to analyze color distribution and rates of selected region. In the cartoon rendering process, we use saliency as a measure to determine visual importance of each area of 3d mesh and we provide a novel cartoon rendering algorithm based on the saliency of 3D mesh. For the fine adjustments of shading style, we propose a user interface that allow the artists to freely add and delete shading to a 3D model. Finally, this paper shows the usefulness of the proposed system through user evaluation.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.12
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• pp.665-682
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• 2007

Line drawing is a widely used style in non-photorealistic rendering because it generates expressive descriptions of object shapes with a set of strokes. Although various techniques for line drawing of 3D objects have been developed, line drawing of 2D images has attracted little attention despite interesting applications, such as image stylization. This paper presents a robust and effective technique for generating line drawings from 2D images. The algorithm consists of three parts; filtering, linking, and stylization. In the filtering process, it constructs a likelihood function that estimates possible positions of lines in an image. In the linking process, line strokes are extracted from the likelihood function using clustering and graph search algorithms. In the stylization process, it generates various kinds of line drawings by applying curve fitting and texture mapping to the extracted line strokes. Experimental results demonstrate that the proposed technique can be applied to the various kinds of line drawings from 2D images with detail control.

• Journal of the Korea Society of Computer and Information
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• v.16 no.8
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• pp.147-155
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• 2011

Map rendering, positioning, database managements are key elements of location based services. Google map and GPS (Global Positioning System) have become a very popular solution for map rendering and positioning, respectively. They are very effective and yet free of charge. However, they cannot be used for an indoor location based service system. We cannot render a building drawing with Google map, we cannot determine a moving object's position when it is indoor. This paper introduces our web services of rendering drawings, indoor positioning, and multimedia contents up-loading and playing so that any programmers can use them in developing indoor location based service systems. In order to experimentally show the efficiency of our web services, we have built a location based contents displaying system for museum visitors with them.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.2
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• pp.110-125
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• 2010

We present a novel scheme for generating line drawings from 2D images, aiming to facilitate effective visual communication. In contrast to conventional edge detectors, our technique imitates the human line drawing process to generate lines effectively and intuitively. Our technique consists of three parts: line extraction, line rendering, and user guidance. In line extraction, we extract lines by estimating a likelihood function to effectively find the genuine shape boundaries. In line rendering, we consider the feature scale and the blurriness of lines with which the detail and the focus-level of lines are controlled. We also employ stroke textures to provide a variety of illustration styles. User guidance is allowed to modify the shapes and positions of lines interactively, where immediate response is provided by GPU implementation of most line extraction operations. Experimental results demonstrate that our technique generates various kinds of line drawings from 2D images enabled by the control over detail, focus, and style.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.102-109
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• 2009

In this paper, we present an algorithm which generates the impossible drawings after the manner of M.C. Escher. A class of the impossible drawings, focused on this paper, depicts the non-realistic configuration such that an ascent (or a descent) looks like keeping on permanently with a height-deceptive loop. We analyze the fact that the ascending direction in the non-realistic illustrations comes not from the physical heights of the objects but from the artist's intended forwarding direction about the loop, which does not have any physical sense of depths. The basic idea to support such impossible drawings is to use a loop of layered depth images (LDIs), where several LDIs are arranged along with the forwarding direction of the loop while having the physically constant heights. The height-deception between two adjacent objects comes from the layer values in the LDIs. In this paper, we propose a NPR system which can manipulate a shape of the loop and layer values of the LDIs and demonstrate several impossible drawings results generated by using our system.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.128-136
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• 2006

The stippling techniques, which represent objects with numerous points using pen and ink. The previous stippling techniques for Non-Photorsealistc Rendering(NPR) use single-colored points to represent the tone of gray image ur the material of surface. This paper presents a new stippling technique with various colored points based on the analysis of color information. By using the color information of the input image on HSV model, we define the color weight function that allows to determine automatically the number and size of points. The color jittering based on Munsell's color model can generate stippling drawings using various colored points to represent the image. Our color stippling method is expected to be used in many areas such as animation, digital art, video processing and CG tool.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.6
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• pp.344-353
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• 2006

In this paper, we present a new algorithm which imitate real pencil strokes. The purpose of research on NPR(Non-Photorealistic Rendering) is simulating automatically manmade artistic expressions such as pen-and-ink illustrations, watercolor paintings, pencil sketches and pastel drawings with computers. Recently, there has been a great deal of research works on NPR. One of them is researching in pencil illustration methods for NPR, and a lot of researchers have investigated into the LIC(Linear Integral Convolution) techniques which would change the initial images into the output images by directional vector field images for generating effects of pencil. However, the LIC techniques can not be applied to real-time drawing tools because they are post processing techniques. This paper presents a real-time pencil strokes algorithm which is based on an observation of how pencils(from 6B to 6H) draw lines. Although this algorithm using some pencil variables and noise generation is simple, it is fast and also can draw real-time pencil strokes similar to real manmade pencil strokes in a GUI drawing tool.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3296-3314
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• 2012

We present a novel approach for the simulation of color pencil effects using line integral convolution (LIC) to produce pencil drawings from images. Our key idea is to use a bilateral convolution filter to simulate the various effects of pencil strokes. Our filter resolves the drawbacks of the existing convolution-based schemes, and presents an intuitive control to mimic the properties of pencil strokes. We also present a scheme that determines stroke directions from the shapes to be drawn. Smooth tangent flows are used for the pixels close to feature lines, and partially parallel flows inside regions. The background is rendered using a flow of fixed direction. Using different styles of stroke directions increases the realism of the resulting images. This approach produces convincing pencil drawing effects from photographs.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.1063-1066
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• 2011

자동차 내비게이션을 비롯한 각종 위치기반서비스가 일상생활에 큰 도움을 준다는 단언에 대하여 반론을 제기하는 사람은 없을 것이다. 고층 건물과 지하 도시가 개발됨에 따라 사람들이 옥내에서 생활하는 시간이 늘어나게 되고 따라서 미구에 옥내위치기반 서비스에 대한 요구가 옥외서비스에 대한 요구보다 더 늘어날 것으로 예상된다. 또한 스마트 폰이 널리 보급되어 있음으로 옥내위치기반서비스가 제공되는 플랫폼으로는 스마트 폰이 제격이다. 옥내위치기반서비스의 사용자 인터페이스에는 당연히 도면이 보여야한다. 이에 본 논문은 도면 출력 안드로이드 애플리케이션을 개발한다.