• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.52-55
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• 2009

With the recent development of virtual reality, it has been actively investigated to develop user interfaces for immersive interaction. Immersive user interfaces improve the efficiency and the capability of information processing in the virtual environment providing various services, and provide effective interaction in the field of ubiquitous and mobile computing. In this paper, we propose an virtual reality platform "My Workspace" which renders an 3D virtual workspace by using an immersive user interface. We develop an interface that integrates an optical see-through head-mounted display, a Wii remote controller, and a helmet with infrared LEDs. It estimates the user's gaze direction in terms of horizontal and vertical angles based on the model of head movements. My Workspace expands the current 2D workspace based on monitors into the layered 3D workspace, and renders a part of 3D virtual workspace corresponding to the gaze direction. The user can arrange various tasks on the virtual workspace and switch each task by moving his head. In this paper, we will also verify the performance of the immersive user interface as well as its usefulness with the usability test.

• Korean Journal of Head & Neck Oncology
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• v.34 no.2
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• pp.29-34
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• 2018

Background/Objectives: The aim of this study was to investigate the diagnostic value of i-scan in the differential diagnosis of oral cavity leukoplakia based on visualization of abnormal vascular features. Materials & Methods: Thirty- one patients with oral cavity leukoplakia were enrolled in the study. Images of their oral cavity obtained using conventional white light endoscopy and an i-scan-enhanced endoscopy (Pentax DEFINA EPK-3000 Video Processors, with Pentax VNLJ10) were reviewed. The microvascular features of the lesions and vascular changes were analyzed and the results were compared with the histopathologic diagnosis. Results: Among the 31 oral cavity leukoplakia patients, 8 (25.8%) patients revealed hyperkeratosis, 10 (31.2%) low-grade dysplasia, 5 (16.2%) high-grade dysplasia and 8 (25.8%) invasive squamous cell carcinoma on histopathologic examination. Using i-scan-enhanced endoscopy, we could found abnormal vascular change with neoplastic neoangiogenesis in most high-grade dysplasia or invasive cancer in oral cavity. (high-grade dysplasia: 4/5 [80.0%], and invasive squamous cell carcinoma: 7/8 [87.5%]). Conclusion: i-scan-enhanced endoscopy could be a useful optical technique for the diagnosis of oral cavity leukoplakia. Our results suggest that i-scan may be a promising diagnostic tool in the early detection of suspected oral mucosal lesion.

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.75-82
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• 2017

We present a new type of receiver-transmitter optical system that can be adapted to the sensor head of a displacement-measuring interferometer. The interferometer is utilized to control positioning error and repetition accuracy of a wafer, down to the order of 1 nm, in a semiconductor manufacturing process. Currently, according to the tendency of scale-up of wafers, an interferometer is demanded to measure a wider range of displacement. To solve this technical problem, we suggest a new type of receiver-transmitter optical system consisting of a GRIN lens-Collimating lens-Afocal lens system, compared to conventional receiver-transmitter using a single collimating lens. By adapting this new technological optical structure, we can improve coupling efficiency up to about 100 times that of a single conventional collimating lens.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.265-272
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• 2009

In this paper, a simple optical method that uses an infrared(IR) cut filter is proposed to minimize variation of eye image by external infrared(IR) sources in a video based head mounted eye tracking system that is used in the field of sports. For this, the IR cut filter is attached to a head mount of the eye tracking system, and the camera with an IR LED is located between the IR cut filter and eye. In this structure, external IR is blocked by the IR cut filter, and the IR intensity on the eye can be controlled by the IR LED. Therefore, the illumination condition of the camera to capture the eye can be stable without being affected by external IR illuminations. To verify the proposed idea, variation of the eye image and intensity of the IR with/without the IR cut filter is measured under various illumination conditions. The measured data show that the IR cut filter method can block external IR effectively, and complex pupil detection algorithms can be replaced by a simple binarized method.

• Korean Journal of Optics and Photonics
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• v.8 no.2
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• pp.161-164
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• 1997

A new hybrid, heterodyne, fiber-optic electric field sensor scheme is presented. In this scheme, a dual polarization, dual frequency, stabilized He-Ne laser is used for the light source of the interferometer, Probe beam is delivered to the sensor head using polarization maintaining fiber. In the sensor head, $LiTaO_3$ electro-optic crystal is used for sensing element. Phase retardation is induced on the dual frquency, dual polarization probe beam due to applied electric field across the crystal. Induced phase retardation is demodulated by in-phase and quadrature demodulation technique. In this way, we can obtain optimum sensitivity for electric field measurement regardless a quasi-static phase difference between two polarization components.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.771-776
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• 2002

Optimal shape of the NFR suspension is studied and developed to improve the dynamic performance and reduce the vibration of the suspension system including a optical head slider. Since accurate position control and stability of the slider motion are highly required in NFR due to the narrower track width and the heavier slider than HDD slider with the low flying height, the dynamic characteristics of the suspension are very important to the mechanical performance of the system. The first natural frequencies in flexural and lateral motion of the suspension are critical factors affecting the dynamics and stability of the flying head, so that the dynamic parameters should be designed properly to avoid an excessive vibration or a crash of the slider on the disk. This paper optimizes the shape of the suspension based on homogenization method in NASTRAN and develops a new suspension shape for NFR system. The suspension is tested on experiment to verify the improvement of the dynamic characteristics.

• International journal of advanced smart convergence
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• v.6 no.1
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• pp.18-25
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• 2017

Recently, VR HMD (virtual reality head mounted display) has been utilized for virtual training, entertainment, vision therapy, and optometry. In particular, virtual reality contents are increasingly used for vision therapy and optometry. Accordingly, high-quality virtual reality contents such as a natural vision of life is required. Therefore, it is necessary to study the content production according to the optical characteristics of the VR HMD. The purpose of this paper is to suggest a proper FOV (field of view) of contents according to the distortion rate. We produced virtual reality contents and obtained distorted images by virtual camera. The distortion rate is calculated by using the distorted image. It is proved that the optimal FOV of the VR content with the minimum distortion is $90{\sim}100^{\circ}$. The results of this study are expected to be applied to the production of high quality contents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.133-138
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• 2001

We studied the optical properties of poly(3-hexylthiophene) for applying to the emitting material of organic electro luminescent device. The infrared spectrum and NMR of synthesized polymer gave good evidence for the conjugation of 3-hexylthiophene monomer unit. We confirmed that poly(3-hexylthiophene) contains the HT(head-to-tail)-HT(head-to-Tail) linkage larger than 65% based on NMR analysis. FTIR and raman spectroscopy show that poly(3-hexylthiophene) has two main vibration levels which have an energy about 0.18eV and 0.36eV. Electronic absorption spectra shifted to the shorter wavelength with increasing temperature, which is related to a conformational transition of the polymer. Photoluminescence spectrum generated at low temperature(10K) is separated at 669nm, 733nm and 812nm that it's because of phonon energy generated from the lattice vibration.

• International Journal of Advanced Culture Technology
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• v.6 no.3
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• pp.201-210
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• 2018

We constructed 3-D images by HMD (Head Mount Display) type and polarization technique through which a training instrument of binocular function based on clinical vision therapy was developed and investigated its demand. To design the instrument that performs Test- Diagnosis - (Prescription) - Training - Treatment we provided a customized training method for the trainers using optical IT instruments of binocular test. Through the contents and the instruments of the vision therapy technology developed in this work we can replace the current vision test instruments to those costing 60% lower price in eye clinics and eye glasses shops. By replacing the existing vision test instruments it is possible to create a new market of the vision therapy in vision training instruments.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1778-1783
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• 2008

A compact and two-dimensional atomic force microscope (AFM) using an orthogonal sample scanner, a calibrated homodyne laser interferometer and a commercial AFM head was developed for use in the nanometrology field. The x and y position of the sample with respect to the tip are acquired by using the laser interferometer in the open-loop state, when each z data point of the AFM head is taken. The sample scanner which has a motion amplifying mechanism was designed to move a sample up to $100{\times}100{\mu}m^2$ in orthogonal way, which means less crosstalk between axes. Moreover, the rotational errors between axes are measured to ensure the accuracy of the calibrated AFM within the full scanning range. The conventional homodyne laser interferometer was used to measure the x and y displacements of the sample and compensated via an X-ray interferometer to reduce the nonlinearity of the optical interferometer. The repeatability of the calibrated AFM was measured to sub-nm within a few hundred nm scanning range.