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비디오 시퀸스에서 움직임 객체 분할과 VOP 추출을 위한 강력한 알고리즘
김준기,이호석,Kim, Jun-Ki,Lee, Ho-Suk 한국정보과학회 2002 정보과학회 컴퓨팅의 실제 논문지 Vol.16 No.2
비디오 객체 분할은 MPEG-4와 같은 객체기반 비디오 코딩을 위한 중요한 구성 요소이다. 본논문은 비디오 시퀸스에서 움직임 객체 분할을 위한 새로운 알고리즘과 VOP(Video Object Plane)추출 방법을 소개한다. 본 논문의 핵심은 시간적으로 변하는 움직임 객체 에지와 공간적 객체 에지 검출 결과를 효율적으로 조합하여 정확한 객체 경계를 추출하는 것이다. 이후 추출된 에지를 통하여 VOP를 생성한다. 본 알고리즘은 첫 번째 프레임을 기준영상으로 설정한 후 두 개의 연속된 프레임 사이의 움직임 픽셀 차이 값으로부터 시작된다. 차이영상을 추출한 후 차이영상에 Canny 에지 연산과 수리형태 녹임 연산(erosion)을 적용하고, 다음 프레임의 영상에 Canny 에지 연산과 수리형태 녹임 연산을 적용하여 두 프레임 사이의 에지 비교를 통하여 정확한 움직임 객체 경계를 추출한다. 이 과정에서 수리형태학 녹임 연산은 잘못된 객체 에지의 검출을 방지하는 작용을 한다. 두 영상 사이의 정확한 움직임 객체 에지(moving object edge)는 에지 크기를 조절하여 생성한다. 본 알고리즘은 픽셀 범위까지 고려한 정화한 객체의 경계를 얻음으로서 매우 쉬운 구현과 빠른 객체 추출을 보였다. Video object segmentation is an important component for object-based video coding scheme such as MPEG-4. In this paper, a robust algorithm for segmentation of moving objects in video sequences and VOP(Video Object Planes) extraction is presented. The points of this paper are detection, of an accurate object boundary by associating moving object edge with spatial object edge and generation of VOP. The algorithm begins with the difference between two successive frames. And after extracting difference image, the accurate moving object edge is produced by using the Canny algorithm and morphological operation. To enhance extracting performance, we app]y the morphological operation to extract more accurate VOP. To be specific, we apply morphological erosion operation to detect only accurate object edges. And moving object edges between two images are generated by adjusting the size of the edges. This paper presents a robust algorithm implementation for fast moving object detection by extracting accurate object boundaries in video sequences.
Baseline JPEG의 color sampling 및 MCU 블록 처리과정
김준기(Jun-Ki Kim),이호석(Ho Suk Lee) 한국정보과학회 1999 한국정보과학회 학술발표논문집 Vol.26 No.1B
본 논문은 Baseline JPEG(Joint Photographic Experts Group)에서 이미지 영상을 화면에 출력하기 위한 샘플링(sampling) 처리과정과 MCU(Minimum Coded Units) 블록의 처리과정을 기술한다. JPEG은 널리 알려져 있는 컬러 정지영상의 압축 표준이다. JEPG 표준에는 여러가지 압축 방법이 있다. 일반적으로 DCT 기반, 순차적 처리, 허프만 코딩을 사용하는 JPEG을 Baseline JPEG 이라고 한다. 모든 JPEG은 Baseline JPEG을 지원해야 한다. JPEG의 응용분야에는 디지털 방식의 전자 정지영상 카메라나 영상 데이터베이스와 같은 저장, 정지화 전송장치나 영상회의 등의 전송, 컬러 프린터등의 인쇄등이 있다. 그러나 많은 응용과 함께 널리 사용됨에도 불구하고 세부적인 처리과정에 대해서는 언급되어 있지 않다. 본 논문에서는 JPEG의 디코딩 과정에서 가장 중요한 부분인 샘플링 처리과정과 MCU 블록 처리과정을 기술한다.
한국농어촌공사 지사 조직의 효율성 및 성과평가의 비교 분석
김준기(Kim Jun ki),김성섭(Kim Seong sup),서상택(Seo Sang taek) 한국농식품정책학회 2017 농업경영정책연구 Vol.44 No.3
This study analyzed the technical efficiency of Korea Rural Community Corporation (KRC) branch offices from 2013 to 2015 and compared the efficiency with the performance evaluation of the same offices. For the study, input oriented Data Envelopment Analysis (DEA) approach was adopted because KRC is a public corporation depending on government budget allocation with output variable uncontrollable. Input variables included labor force and total cost and output variables included gross margin and area under control. The results showed that average technical efficiency of the branch offices ranged from sixty one percent to sixty eight percent during the period, which implied that the brach offices could increase technical efficiency by reallocating both inputs. In addition, the rankings between performance evaluation result and technical efficiency were not identical among branch offices. This meant that the performance evaluation system was not appropriate for increasing management efficiency. We suggested the mixed use of both measures to increase a mid- and longterm management efficiency and reach a short-term management goal.
소아와 성인에서 태선양 비강진의 임상 및 병리조직학적 차이에 대한 고찰
김준기 ( Jun Ki Kim ),이지연 ( Ji Yeoun Lee ),윤태영 ( Tae Young Yoon ) 대한피부과학회 2015 대한피부과학회지 Vol.53 No.9
Background: Pityriasis lichenoides, an inflammatory skin condition of unknown etiology affecting both children and adults encompasses a clinical spectrum between pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC). Although reported to follow a more self-limiting course in children compared with adults, there are a few studies comparing pityriasis lichenoides in both age groups in Korea. Objective: The aim of this study was to evaluate the clinicopathological features, overall efficacy of treatments, and disease outcomes in children and adults diagnosed with pityriasis lichenoides. Methods: This was a retrospective study of pityriasis lichenoides at our center between January 2003 and December 2013. Clinical manifestations and histopathological features of 54 patients with pityriasis lichenoides were analyzed. We also evaluated the clinical course in children and adults according to Gelmetti’s classification. Results: In this study, 36 patients were children (mean age 11.6 years, range 3∼18 years) and 18 patients were adults (mean age 34.7 years, range 19∼55 years). Lesions on the face were observed more commonly in children (n=18, 50%) compared with adults (n=1, 5.5%). Of the clinical features, vesiculation, crust and pigmentary changes were significantly more common in children than in adults. After treatment, 12 children (33.3%) and 10 adults (55.6%) went into complete remission. Histopathological features were not significantly different between children and adults. They just showed the difference between PLEVA and PLC. Dyskeratosis, epidermal necrosis, intraepidermal red blood cell (RBC) trapping, and RBC extravasation in the dermis were more prominent in PLEVA than in PLC. By Gelmetti’s classification, disease duration was longer in children with the peripheral type (38.5 months) than in children with the diffuse and central types. In adults, the diffuse type lasted longer (24.5 months) than the central and peripheral types. Conclusion: This study suggests that, compared with adults, pityriasis lichenoides in children is more likely to follow an unremitting course, with more facial/acral involvement and pigmentary changes and a poorer response to conventional treatment modalities. Applying the Gelmetti``s classification, disease duration was longer in children with the peripheral type than other types. However, in adults, the duration was longer with the diffuse type. (Korean J Dermatol 2015;53(9):693∼699)