• 한국가시화정보학회지
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• 제1권1호
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• pp.92-97
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• 2003

A new Stereoscopic PTV was developed using two CCD cameras, stereoscopic photogrammetry based on a 3D-PTV principle. Virtual images were produced for the benchmark test of the constructed Stereoscopic PTV technique. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on the Genetic Algorithm based 3D-PTV technique. The constructed Stereoscopic PTV technique was tested on the standard images of the impinged jet proposed by VSJ. The results obtained by the constructed system showed good agreements with the original data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1772-1777
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• 2004

The performances of the newly constructed Stereoscopic PTV and Stereoscopic PIV which had been completed based on a 3D-PTV principle are tested using the Standard Images. Virtual images were produced for the benchmark tests of the constructed two Stereoscopic techniques. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The Standard data of LES are on the impinged jet proposed by VSJ. It is shown that the results obtained by Stereoscopic PTV have better reliability than those by Stereoscopic PTV.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.11-14
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• 2002

A new high-definition stereoscopic PTV was constructed using two CCD cameras, stereoscopic photogrammetry based on a 30-PTV principle. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 30-PTV technique. The constructed Stereoscopic PTV technique was tested on the standard images of the Impinging jet proposed by VSJ. The results on the turbulent properties of the jet obtained by the constructed system showed a good agreement with the original LES data.

• 대한기계학회논문집B
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• 제30권3호
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• pp.215-221
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• 2006

A stereoscopic particle tracking velocimetry (SPTV) technique based on the 2-frame hybrid particle tracking velocimetry (PTV) method was developed. The expansion of 2D PTV to SPTV is facilitated by the fact that the PTV method tracks individual particle centroids. To evaluate the performance and measurement accuracy of the present SPTV technique, it was applied to flow images of rigid body translation and synthetic standard images of jet shear flow and impinging jet flow. The data processing routine and measurement uncertainty of the SPTV technique are compared with those of conventional stereoscopic particle image velecimet.y (SPBV). In addition, the centroid translation effect of 2D particle image velocimetry (PIV) is defined and its effect on SPIV measurements is discussed. Compared to the SPIV method, the SPTV technique has inherited merits of concise and precise velocity evaluation procedures and provides better spatial resolution and measurement accuracy.

• 대한방사선치료학회지
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• 제22권2호
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• pp.131-134
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• 2010

목 적: TOMO 치료는 일반 방사선 치료와 달리 상대적으로 긴 Beam time과 온도에 민감한 CT 검출기 등으로 치료실 내 적정온도($20{\sim}21^{\circ}$)를 유지하기 위하여 자체 Cooling system 이외에도 항온 항습기를 작동시키고 있다. 이로 인해 TOMO 치료실 내 온도가 저하되어 환자들의 체온 유지를 위해서 치료 부위에 이불 등을 덮어준다. 따라서 이러한 물질들이 조직 내 선량에 어떠한 변화를 주는지 알아보고자 한다. 대상 및 방법: 조직 내 선량변화를 비교하기 위하여 치즈팬텀(Cheese Phantom)을 사용하였고, CT-simulation 촬영 후 치즈팬텀의 중심점을 PTV (Planning Target Volume, 치료계획 표적 용적)로 설정하여 Daily dose 200 cGy, 3회의 치료계획을 세웠다. PTV, PTV+7 cm, PTV+14 cm, 총 세지점에서 Ion chamber를 사용하여 팬텀에 아무 물질도 덮지 않은 상태에서 선량을 측정하고, 치료 중 가장 많이 사용하는 이불을 포함한 빈번하게 사용하는 4가지 물질(방포 0.8 mm, 가운 1.4 mm, 담요 3.3 mm, 이불 13.7 mm)을 팬텀에 덮었을 때의 선량을 동일한 위치에서 각각 3회 측정하여 비교 분석하였다. 결 과: PTV, PTV+7 cm, PTV+14 cm 지점에서 아무물질도 덮지 않은 상태에서 측정한 결과와 4가지 물질(방포, 가운, 담요, 이불)을 덮은 상태에서 측정한 결과를 비교해본 결과, PTV에서 각각 -0.17%, -0.44%, -0.53%, -0.9% 변화하였고, PTV+7 cm에서 각각 -0.04%, +0.07%, +0.06%, +0.07% 변화하였고, PTV+14 cm에서 각각 0%, -0.06%, -0.02%, +0.6% 변화하였다. 결 론: 본 실험 결과 TOMO 치료 시 환자들의 체온 유지를 위하여 사용하는 물질에 의해 PTV에서는 물질의 두께에 비례하여 감소하는 것으로 나타났다. 그러나 PTV+7 cm 지점에서는 미세한 변화를 보였고, PTV+14 cm 지점에서 선량은 조금 증가하는 것으로 나타났다. 세지점 모두 그 차이가 치료 허용오차 범위인 ${\pm}3%$로 안에 들어오는 것으로 확인이 되어 치료효과에는 큰 영향을 미치지 않을 것으로 사료된다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.88-91
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• 2008

A Hybrid-Genetic-Algorithm based 3D-PTV has been constructed by introducing the conventional GA-3D-PTV. The measurement system consists of two-high-definition-cameras(1k ${\times}$ 1k), a Nd-Yag laser and a host computer. The system has been used to measure the wake of a cylinder. The Reynolds number is 1120. The structures of the wake have been quantified in detail than the results obtained ever before.

• 한국가시화정보학회지
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• 제8권4호
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• pp.26-30
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• 2010

A PTV algorithm was constructed using a linear transformation, in which the merits of the conventional PIV and PTV were adopted. In PIV calculations, the obtained velocity vectors are affected by the filtering effects by its calculation principle. PTV techniques are widely used for their excellences of measuring small scaled flows, such as nano and bio flows. However, PTVs produce vector errors due to interpolation process. To overcome these problems, a hybrid PTV algorithm was constructed by combining PTVs' and PIVs' benefits using a linear transformation. The Taylor-Green vortex flows were generated for the tests of vorticity calculations. The conventional gray-level cross-correlation PIV technique and 2-Frame PTV technique were tested for the same flows for comparisons with those obtained by the constructed hybrid algorithm. The excellence of the constructed hybrid algorithm was validated through an actual experiment on the cylinder wake.

• 한국수자원학회논문집
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• 제34권4호
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• pp.327-333
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• 2001

PTV는 비디오 카메라로 기록된 영상의 분석을 통하여 흐름속도를 측정한다. 이러한 PTV 방법을 이용하여 유사의 침강속도를 측정하였다. 실험을 통해 측정된 정지 유체내 유사의 침강속도를 기존문헌에 제시된 값과 비교 분석한 결과, 침강속도 측정에 PTV를 이용할 수 있음이 입증되었다. 따라서 PTV를 이용하면난류흐름 중의 침강속도 측정이 가능해져 난류흐름 중의 침강속도 특성 규명에 기여할 수 있을 것이다.

• 대한기계학회논문집B
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• 제22권6호
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• pp.874-887
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• 1998

A 2-frame PTV (particle tracking velocimetry) system using the concept of match probability between two consequent image frames has been developed to obtain instantaneous velocity fields. The overall 2-frame PTV system including image pre-processing, tracking algorithm and post-processing routine was implemented to apply to real flows. The developed 2-frame PTV system has several advantages such as high recovery ratio of velocity vectors, low error ratio and small computational time compared with the conventional 4-frame PTV and the FFT-based cross-correlation PIV technique. The 2-frame PTV system was applied to a turbulent channel flow over a rectangular block to check its reliability and usefulness. Total 96 sequential image frames have been captured and processed to get both mean and fluctuating velocity vector fields over the recirculating region. The mean velocity and turbulent intensity profiles were well agreed with hte LDV measurements in the separated region behind the block. Time-averaged reattachment length is about 6.3 times of the block height.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.511-512
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• 2002

A new stereoscopic PTV was developed using two CCD cameras, stereoscopic photogrammetry based on a 3D-PTV principle. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The constructed Stereoscopic W technique was tested on the standard images of the impinged jet proposed by VSJ. The results on the turbulent properties of the jet obtained by the constructed system showed a good agreement with the original LES data.