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3차원 입체 변환을 위한 MPEG 압축 데이터에서의 영상 처리 기법
김만배 한국방송공학회 1998 한국방송공학회 학술대회 Vol.1 No.1
The conversion of monoscopic video to 3D stereoscopic video has been studied by some pioneering researchers. In spite of the commercial potential of the technology, two problems have bothered the progress of this research area: vertical motion parallax and high computational complexity. The former causes the low 3D perception, while the hardware complexity is required by the latter. The previous research has dealt with NtSC video, thus requiring complex processing steps, one of which is motion estimation. This paper proposes 3D stereoscopic conversion method of MPEG encoded data. Our proposed method has the advantage that motion estimation can be avoided by processing MPEG compressed data for the extraction of motion data as well as that camera and object motion in random directions can be handled.
차량 속도 측정의 실무적용을 위한 테이프스위치 센서 방식과 영상 프레임 분석방법의 비교연구
김만배,홍유식,현철승,유성준 대한전자공학회 2006 電子工學會論文誌-TC (Telecommunications) Vol.43 No.9
In Korea, the vehicle enforcement system(VES) detects speeding vehicle using two inductive loop detectors. And the speed reliability of theirs are evaluated through the analysis of image frame which is captured from video camera. This method is validated to evaluate VES on Korea Laboratory Accreditation Scheme(KOLAS) but it needs much time and expense for the analysis of image frame. Because the number of VES are increasing rapidly, the requirement of new evaluation method is necessary. On this paper, the tape switch sensor as a substitution of existing method was introduced and its application on the site are discussed. On the site test, we compared the tape switch sensor on the speed measurement of vehicle with the video image frame. As a result, we have founded that the tape switch sensor is evaluated to be feasible system on site in respect to measure the overspeed vehicle. 현재 국내 도로에 설치되어 있는 무인교통단속장비는 속도 측정을 위해 루프 검지기를 이용하고 있으며 동 검지기의 신뢰도 평가는 주로 비디오카메라 촬영을 통한 영상프레임분석 방법을 이용하여 왔다. 그러나 영상프레임분석 방법은 국가 공인검사방법으로 인정받고 있지만 무인교통단속장비의 검정 분석 대상이 증가하면 증가할수록 자료 분석에 소요되는 경제적 비용과 소요 시간이 큰 폭으로 늘어나 실무적 어려움을 갖게 되었다. 따라서 차량 속도 측정의 실무적용의 용이성을 확보하기 위해 기존의 영상 프레임 분석 방법을 대체 내지는 보완하여 속도를 실시간으로 분석할 수 있는 새로운 속도 측정 방법의 도입이 요구되고 있다. 본 연구에서는 영상 프레임 분석 방법을 대체하고 속도정확도를 실시간으로 분석할 수 있는 방안으로써 테이프 스위치 센서를 이용한 속도 측정 시스템을 통하여 동 시스템의 신뢰도 및 현장 적용 여부를 검토하였다. 본 연구에서 구성한 테이프 스위치 센서를 이용한 속도 측정 방식과 프레임분석에 의한 기존 방식과의 비교분석한 결과, 대체 사용하여도 무방한 것으로 평가되었다. 따라서 테이프스위치 센서를 이용한 속도측정 장치는 교통단속시스템의 실무적 검수검정을 단시간 내에 수행할 수 있는 장점이 있어 향후 속도측정용 시험 장비로써 현장 적용 가능성이 매우 높은 것으로 판단된다.
김만배,박창용 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5
An experimental study on heat transfer and pressure drop characteristics was performed at single phase flow in two Brazed plate heat exchangers (BPHEs) with different geometries. The corrugation density of one of the BPHE (Type II) was two times as high as that of the other BPHE (Type I). The hydraulic diameter of the type II BPHE was 2.13 mm, which was 38 % smaller than that of the type I BPHE. Also, the cross section shape of the flow channels for the type II BPHE was different from that for conventional BPHEs due to the unusual corrugation patterns and brazing points. The experimental conditions for temperatures were varied from 4.6 °C to 49.1 °C, and for mass flow rates were changed from 0.07 kg/s to 1.24 kg/s. The measured results showed that pressure drop in the type II BPHE was about 110 % higher than that in the type I BPHE. Nu of the type II was higher than that of the type I BPHE and the enhancement became larger with the increase of Re at the ranges above 800. New correlations for f F and Nu were proposed by this study and their prediction accuracy could be improved by considering the surface enlargement factor in the correlations. The performance evaluation of the two BPHEs was performed by (j/f F1/3 ) which represented the ratio of heat transfer and pressure drop performance. Also, a new parameter, the capacity compactness of PHE, was proposed and it presented the PHE capacity per unit volume and unit log mean temperature difference. The comparison showed that the two BPHEs had similar values of the (j/f F1/3 ), whereas they had significantly different values of the capacity compactness. The capacity compactness of the type II BPHE was 1.5 times higher than that for the type I BPHE.