• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.12
• /
• pp.1087-1092
• /
• 2010

A micro 3D-PTV system has been constructed using a single camera system. Two viewing holes were created behind the object lens of the microscopic system to construct a stereoscopic viewing image. A hybrid recursive PTV algorithm was used. A concept of epipolar line was adopted to eliminate many spurious candidates. Three-dimensional velocity vector fields were obtained by calculating the three-dimensional displacements of particles that were identified as being identical. The system consists of a laser light source (Ar-ion, 500 mW), one high-definition camera ($1028{\times}1024$ pixels, 500 fps), a circular plate with two viewing holes, and a host computer. The performance of the developed algorithm was tested using artificial images. The characteristic of the vector recovery ratio was investigated for the particle numbers. A micro backward-facing step channel ($H{\times}h{\times}W:\;36{\mu}m{\times}70{\mu}m{\times}3000{\mu}m$) was measured using the developed measurement system. The results were in good qualitative agreement with other results.

• Journal of Internet Computing and Services
• /
• v.11 no.6
• /
• pp.21-29
• /
• 2010

In this paper, we propose the system which detects the speaker, who is speaking currently, among a number of users. A proposed speaker detection system based on stereo vision and audio is mainly composed of the followings: a position estimation of speaker candidates using stereo camara and microphone, a current speaker detection, and a speaker information acquisition based on a mobile device. We use the haar-like features and the adaboost algorithm to detect the faces of speaker candidates with stereo camera, and the position of speaker candidates is estimated by a triangulation method. Next, the Time Delay Of Arrival (TDOA) is estimated by the Cross Power Spectrum Phase (CPSP) analysis to find the direction of source with two microphone. Finally we acquire the information of the speaker including his position, voice, and face by comparing the information of the stereo camera with that of two microphone. Furthermore, the proposed system includes a TCP client/server connection method for mobile service.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.8
• /
• pp.35-46
• /
• 2009

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.4 s.193
• /
• pp.44-56
• /
• 2007

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.07a
• /
• pp.197-197
• /
• 2004

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.8
• /
• pp.758-769
• /
• 1991

We have investigaed the radio data system which is used for the VHF/FM streo broadcasting system. The RDS system has the I6 important service features which is given by the digital multiplexed modulation method above the FM stereo baseband spectrum. The related cicuit system and general-purpose micro-controller have been applicated for the demodulation and processing of transmitted digital information at the rate of 1187.5bps, and we have developed the receiver system which performs the primary 5 features. The develpoed system has the complete compatibility with the conventional FM-car stereo receiver, we have analyzed the received RDS signal via the hardware implementation.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.10
• /
• pp.93-99
• /
• 2010

A nano-stereolithography is the direct patterning process with a nanoscale resolution using twophoton absorption induced by a femtosecond laser. However, in the majority of the works, the fabrication of 3D microstructures have been done only onto transparent glass due to the use of an oil immersion objective lens for achieving a high resolution. In this work, the coaxial illumination and the auto-focusing system are proposed for the direct patterning of nano-precision patterns on an opaque substrate such as a silicon wafer and a metal substrate. Through this work, 3D polymer structures and metallic patterns are fabricated on a silicon wafer using the developed process.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.2
• /
• pp.68-77
• /
• 2005

The purpose of a spatial audio system is to give a listener an impression as if he were present in a recorded environment when its sound is reproduced. For this purpose a dummy head microphone is generally used. Because of its human-like shape, dummy head microphone can reproduce spatial images through headphone reproduction. However, its shape and size are restriction to public use and it is difficult to convert the output signal of dummy head microphone into a multi-channel signal for multi-channel environment. So, in this paper, we propose a multi-channel 3D microphone technology. The multi-channel 3D microphone acquire a spatial audio using five microphones around a horizontal plane of a rigid sphere and through post processing, it can reproduce various reproduction signals for headphone, stereo, stereo dipole, 4ch and 5ch reproduction environments. Because of complex computation, we implemented H/W based post processing system. To verily the Performance of the multi-channel 3D microphone, localization experiments were Performed. The result shows that a front/back confusion, which is the one of common limitations of conventional dummy head technology, can be reduced dramatically.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.339-342
• /
• 2000

본 논문에서는 DSP와 RISC 마이크로 콘트롤러의 결합으로 구성된 이중 코어 DSP를 이용하여 휴대장치에 적합한 저전력 MPEC-2 계층-III 복호화기의 구조를 제안하고 실시간 시스템을 구현하였다. 제안된 시스템은 디지털 오디오 데이터 처리부와 시스템 제어 정보처리부로 나누어 병렬처리가 가능한 구조이다. 디지털 오디오데이터 처리부에서는 DSP의 강력한 산술연산기능으로 MPEG 복호화 알고리듬을 수행하며 시스템 제어부에서는 마이크로 콘트롤러의 장점인 저가, 저전력의 제어 기능으로 사용자 인터페이스 및 파일 관리, 비트스트림 제어를 담당하도록 구성된다. 입력부에서는 Multi Meadia Card(MMC)를 지원하고, PC와 호환 가능하도록 파일 관리 시스템으로 운용되며 직렬 통신의 데이터 전송과 16비트 해상도 및 최대 48kHz 표본화주파수로 스테레오 출력이 가능하다. 구현된 시스템은 이중 코어를 이용하여 DSP의 연산량 및 동작속도의 감소로 인한 저가, 저전력의 효과로 인해 휴대장치에 적합하다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.7 s.238
• /
• pp.998-1004
• /
• 2005

A nano-stereolithography (NSL) process has been developed for fabrication of 3D shell structures which can be applied to various nano/micro-fluidic devices. By the process, a complicated 3D shell structure on a scale of several microns can be fabricated using lamination of layers with a resolution of 150 nm in size, so it does not require the use of my sacrificial layer or any supporting structure. A layer was fabricated by means of solidifying liquid-state monomers using two-photon absorption (TPA) induced using a femtosecond laser processing. When the polymerization process is finished, unsolidified liquid state resins can be removed easily by dropping several droplets of ethanol fur developing the fabricated structure. Through this work, some 3D shell structures, which can be applied to various applications such as nano/micro-fluidic devices and MEMS system, were fabricated using the developed process.