• Korean Journal of Optics and Photonics
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• v.7 no.2
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• pp.112-119
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• 1996

TM polarized photon tunneling time and the position where TM photons appear after two-dimensional tunneling in a frustrated total internal reflection (FTIR) structure are calculated. This is done by converting the FTIR tunneling problem of TM photons to an electron tunneling problem with a position-dependent effective mass for a heterostructure potential barrier. Derived results are compared with TE photon cases.

• 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.

• Journal of Adhesion and Interface
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• v.13 no.2
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• pp.73-84
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• 2012

The transfer mechanism of optical information at the interface of air and glass (the air-glass IF) has been investigated by thoroughly fulfilling the theoretical and experimental analyses regarding the FTIR (Frustrated Total Internal Reflection) and moisture effects on the fingerprint onto a glass cup with water. As for the fingerprint onto a glass cup with water its image was observed to be very vivid, which turned out to be due to the difference between the two light intensities reflected on the air-glass IF and the wet fingerprint ridge by manipulating the optical theories such as Fresnel relation, Snell's law, FTIR, GT (general transmission) and so on. In addition, the experimental inspection for FTIR and moisture effects on the fingerprint image also evidenced the fact that the vivid fingerprint image originated from the moisture effect rather than the FTIR phenomenon.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.553-560
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• 2007

본 논문에서는 양손의 터치를 인식하여 실시간 상호작용이 가능한 테이블 탑 디스플레이 시스템 및 구현 알고리즘에 대해 기술한다. 제안하는 시스템은 FTIR(Frustrated Total Internal Reflection) 메커니즘을 기반으로 제작되었으며 multi-touch, multi-user 방식의 손 제스처 입력이 가능하다. 시스템은 크게 영상 투영을 위한 빔-프로젝터, 적외선 LED를 부착한 아크릴 스크린, Diffuser 그리고 영상을 획득하기 위한 적외선 카메라로 구성되어 있다. 시스템 제어에 필요한 제스처 명령어 종류는 상호작용 테이블에서의 입력과 출력의 자유도를 분석하고 편리함, 의사소통, 항상성, 완벽함의 정도를 고려하여 규정하였다. 규정된 제스처는 사용자가 상호작용을 위해 스크린에 접촉한 손가락의 개수, 위치, 그리고 움직임 변화를 기준으로 세분화된다. 적외선 카메라를 통해 입력받은 영상은 잡음제거 및 손가락 영역 탐색을 위해 간단한 모폴로지 기법이 적용된 후 인식과정에 들어간다. 인식 과정에서는 입력 받은 제스처 명령어들을 미리 정의해놓은 손 제스처 모델과 비교하여 인식을 행한다. 세부적으로는 먼저 스크린에 접촉된 손가락의 개수를 파악하고 그 영역을 결정하며 그 후 그 영역들의 중심점을 추출하여 그들의 각도 및 유클리디언 거리를 계산한다. 그리고 나서 멀티터치 포인트의 위치 변화값을 미리 정의해둔 모델의 정보와 비교를 한다. 본 논문에서 제안하는 시스템의 효율성은 Google-earth를 제어하는 것을 통해 입증될 수 있다.

• International Journal of Advanced Culture Technology
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• v.1 no.1
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• pp.15-18
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• 2013

This paper describes new gestures on the Multi-touch table. The 2 new gestures with 3 fingers are used for minimizing of all windows that is already open and converting Aero mode. We also implement a FTIR (Frustrated Total Internal Reflection) Multi-touch table that consists of sheet of acrylic, infrared LEDs, camera and rear projector. The operation of proposed gestures is verified on the implemented Multi-touch table.

• 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 the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.13-18
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• 2010

Most of the research in the multi-touch area is based on the FTIR(Frustrated Total Internal Re리ection), which is just implemented by using the previous approach. Moreover, there are not the software solutions to improve a performance in the multi touch-blobs detection or the user gesture recognition. Therefore, we implement a multi-touch table-top display that is based on the DI(Diffused Illumination), the improved touch-points detection and user gesture recognition. The proposed method supports a simultaneous transformation multi-touch command for objects in the running application. Also, the system latency time is reduced by the proposed ore-testing method in the multi touch-blobs detection processing. Implemented device is simulated by programming the Flash AS3 application in the TUIO(Tangible User Interface Object) environment that is based on the OSC(Open Sound Control) protocol. As a result, Our system shows the 37% system latency reduction, and is successful in the multi-touch gestures recognition.

• Journal of the Optical Society of Korea
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• v.8 no.1
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• pp.34-52
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• 2004

Over the past decade the experimental technique of THz time domain spectroscopy (㎔- TDS) has proved to be a versatile method for investigating a wide range of phenomena in the ㎔ or far infrared spectral region from 100 ㎓ to 5 ㎔. This paper reviews some recent results of the Ultrafast ㎔ Research Group at Oklahoma State University using ㎔-TDS as a characterization tool. The experimental technique is described along with recent results on ㎔ beam propagation and how ㎔ beam profiles arise from propagation of pulse fronts along caustics. To illustrate how spatio-temporal electric field measurements can determine material properties over a wide spectral range, propagation of ㎔ pulses through systems exhibiting frustrated total internal reflection (FTIR) are reviewed. Finally two potential metrology applications of ㎔-TDS are discussed, thin film characterization and non-destructive evaluation of ceramics. Although ㎔-TDS has been confined to the research laboratory, the focus on application may stimulate the adoption of ㎔- TDS for industrial or metrology applications.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.19-21
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• 2008

본 논문에서는 테이블 형이 아닌 스탠드형 테이블 탑 디스플레이에 대한 연구를 다루고 있다. 스크린에 대한 터치를 인식으로 입력을 받아들이므로 TouchFace III 라고 명명하고 있으며, 기존에 개발되었던 두 대의 테이블 탑 디스플레이와는 형태에서 차별을 두고 있다. TouchFace III 시스템은 FTIR(Frustrated Total Internal Reflection : 내부 전반사 장애 현상) 방식이 아닌 TouchLight방식과 HoloWall방식을 조합하여 시스템을 구성하였다. 그래서 스크린에서의 직접적인 손터치 뿐만 아니라, 스크린에 반사되는 손형상에 대한 제스처까지도 인식할 수 있도록 연구중에 있다. 이는 협업을 강조하는 테이블 탑 디스플레이의 컨셉에 어울리며 한 디바이스를 이용하여 동시에 여러사용자가 디바이스를 조작하는 것을 가능하게 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.163-165
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• 2008

본 논문은 공간적인 제약을 벗어난 협업을 위하여 사용자가 서로의 모습을 확인할 수 있고, 직접적인 터치에 공간적인 터치(손 형상 및 제스처 인식)를 통하여 보다 자유롭고 직관적인 시스템 제어를 추구 하는 테이블 탑 디스플레이를 제안한다. 테이블 탑 디스플레이는 FTIR(Frustrated Total Internal Reflection : 내부 전반사 장애 현상) 방식이 아닌 TouchLight방식과 HoloWall방식을 조합하여 손 형상 및 제스처 인식을 할 수 있도록 설계하였다.