• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.1-12
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• 2011

Large-sized multi-touch screen is usually made using infrared rays. That is because it has technical constraints or cost problems to make the screen with the other ways using such as existing resistive overlays, capacitive overlay, or acoustic wave. Using infrared rays to make multi-touch screen is easy, but is likely to have technical limits to be implemented. To make up for these technical problems, two other methods were suggested through Surface project, which is a next generation user-interface concept of Microsoft. One is Frustrated Total Internal Reflection (FTIR) which uses infrared cameras, the other is Diffuse Illumination (DI). FTIR and DI are easy to be implemented in large screens and are not influenced by the number of touch points. Although FTIR method has an advantage in detecting touch-points, it also has lots of disadvantages such as screen size limit, quality of the materials, the module for infrared LED arrays, and high consuming power. On the other hand, DI method has difficulty in detecting touch-points because of it's structural problems but makes it possible to solve the problem of FTIR. In this thesis, we study the algorithms for effectively correcting the distort phenomenon of optical lens, and image processing algorithms in order to solve the touch detecting problem of the original DI method. Moreover, we suggest calibration algorithms for improving the accuracy of multi-touch, and a new tracking technique for accurate movement and gesture of the touch device. To verify our approaches, we implemented a table-based multi touch screen.

• Journal of Adhesion and Interface
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• v.14 no.2
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• pp.57-67
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• 2013

The incompletion of TIR (Total Internal Reflection) in FTIR (Frustrated Total Internal Reflection) touch screen has been investigated as follows. Assuming a 3 layer thin film of medium1 ($n_1$)-medium2 ($n_2$)-medium3 ($n_3$) with refraction indices of $n_1=n_3{\neq}n_2$, it was theoretically proven that FTIR or OT (ordinary transmission) phenomena might happen through medium2 from medium1 to medium3 relying on relative difference in $n_1(=n_3)$ and $n_2$, and that the formulae for FTIR and OT could be transformed into each other depending on the number state (imaginary or real) of the light wave phase. In parallel to the theoretical analysis, the incompletion of TIR in acrylate due to external contacts was also elucidated from the experimental and phenomenological viewpoints. On the basis of this considerate work, we explained how to improve the touching performance for better FTIR touch screen.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.85-94
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• 2012

In this paper, we develop the new gestures of screen control with fingers on the FTIR multi touch table. It also describes recognition of mobile devices on the table using infrared camera. The FTIR multi touch table was incovenient to the existiog Bluetooth connection, because it is not provided with an HID(Human Input Device) interface. The proposed data transmission method using mobile device is to relieve the inconvenience of the data transfer and proceed more effectively. The new gestures and data transmission method is verified by FTIR multi touch table that is implemented for testing.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.25-29
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• 2010

In this paper, we implement a multi-touch system using FIDR. The implementation consists of hardware manufacture and development of image processing system. In the hardware system, touch screen, infrared LED placements and infrared camera are made. The image processing procedure is to extract each pointer's coordinates from image data and includes binary-coding, noise-elimination, labeling and calculation of mass center. From the implementation, we are able to make a multi-touch system with considerably lower cost than the existing ones.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.80-83
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• 2009

본 논문에서는 AR 보드 게임을 위한 FTIR 방식의 멀티 터치 스크린 시스템을 제안한다. 기존 보드 게임은 카드의 정보나 위치등 다양한 정보를 보여주면서 사용자와의 상호작용에 있어서 버튼과 같은 단순한 형태의 입력을 요구한다. 이러한 낮은 상호작용을 보완하기 위해서 다양한 형태의 패턴 등을 입력할 수 있는 멀티 터치 스크린 시스템을 적용한 텐저블 사용자 인터페이스를 제공하여 사용자로 하여금 더 많은 상호작용과 높은 몰입감을 제공하고자 한다. 본 논문에서 제안하는 시스템은 다음과 같이 구성된다. 먼저, 텐저블 사용자 인터페이스를 위해서 Jefferson Y. Han이 제안한 시스템과 유사한 형태의 FTIR 방식의 멀티 터치 스크린을 테이블 탑 형태로 제작한다. 또한, 스크린 위의 카드를 인식하기 위해서 특정한 모양의 패턴을 적용한 적외선 반사지를 카드에 입힌 후, DI 방식을 사용하여 카드의 고유한 정보를 인식할 수 있도록 하였다. 마지막으로 사용자에게 인터페이스의 확장뿐만 아니라 시각적으로 높은 몰입감을 제공하기 위해 Bimber가 제안한 Virtual Showcase를 적용하였다. 이러한 시스템을 통해 사용자는 이전의 단조로운 형태의 게임에서 벗어나 훨씬 다양하고 높은 몰입감을 즐길 수 있게 되었다.