Look-Up Table 기법을 이용한 하프톤 영상의 워터마킹 알고리즘

천인국 순천향대학교 부설 산업기술연구소 2004 순천향 산업기술연구소논문집 Vol.10 No.2

In this paper, we propose a new watermark algorithm for halftone images using LUT(Look-Up Table) method. In the proposed method, watermark bits are hidden at pseudo-random locations within a halftone image. To remove the distortions due to the inserted watermark bits and increase the invisibility of watermark, the best halftone pixel are chosen from LUT considering both of the contone value of the current pixel and its neighborhood pixels. The LUT halftoning will require no arithmetic operations other than memory access. The LUT is built from a sample set of images and halftones of these images. In order to be robust to geometrical modification like cropping or rotation, we insert the same watermark periodically into halftone images. Experiments using printed and scanned images show that the proposed method is a robust method to the geometrical modification and to hide the large amount of data within a halftone image without noticeable distortion.

제46차 대한핵의학회 추계학술대회 : 일반연제 ; C-11 Acetate 및 리스트모드 3D PET/CT를 이용한 심근 산소소모량의 측정

천인국,황경훈,김진수,신희원,최준봉,이재성,구찬모,이우철,윤민기,이민경,최원식 대한핵의학회 2007 핵의학 분자영상 Vol.41 No.5

웹기반에서의 지역화 학습을 위한 코스웨어 설계 및 구현

천인국,이명순 순천향대학교 부설 산업기술연구소 2002 순천향 산업기술연구소논문집 Vol.8 No.1

Nowadays in most school, teachters are trying vigorously about web-based instruction because Internet lines are constructed as computer and multimedia equipment are supplied. In the case of social studies, because students must find data about the local community. the person who has resources about the local community can be an effective teacher. but it could be impossible in real situation because of time, economical condition, Therefore in this research, deveoping regional learning courseware which enables to experience indirectly by various method makes it possible for students to understand more about their local communties and be proud of their local commnuties. As result students are more interested in local community learning and can lead their own studying by themself.

파티션 모델을 이용한 거리 영상 분할

천인국 순천향대학교 부설 산업기술연구소 1998 순천향 산업기술연구소논문집 Vol.3 No.3

본 연구에서는 거리 영상을 분할하기 위하여 Geman등이 주장한 파티션 모델을 적용하였다. 화소배열과 라벨 배열, 에너지 함수, 차이 측정 함수등을 정의하였으며 차이 측정 함수는 두 영역간의 평면 근사 오차를 이용한다. 거리 영상 분할 문제는 입력 영상이 주어졌을 때 가장 확률적으로 높은 라벨 상태를 찾는 것으로 정의된다. 특정한 라벨 상태의 확률은 깁스(Gibbs) 확률 분포로 정의되고 사후 최대 확률 상태는 전역 에너지 최소 상태에 해당한다. 에너지 상태는 차이 함수와 금지 패턴의 갯수로 이루어진다. 두 개의 라벨 사이의 낮은 차이값은 같은 라벨값이 되도록 유도되고 큰 차이값은 서로 다른 라벨을 장려한다. 매우 작은 영역은 반복적인 탐색 처리 과정에서 금지 상태로 정의된다. 라벨의 최종 상태는 제한 최적화의 일종으로 찾아진다. 실제 거리 영상에 대해서 실험한 결과가 제시된다.

마코프 랜덤 필드를 이용한 거리영상에서의 윤곽선 검출

천인국 순천향대학교 부설 산업기술연구소 1995 순천향 산업기술연구소논문집 Vol.1 No.1

This paper deals the boundary detection of range image. The edge detection problem is defined as an energy minimization problem using Markov Random Field and the minimum energy state is found using iterative method. Firstly range and its gradient image are smoothed preserving jump and roof edges respectively using line process concept one after another. Then jump and roof edges are extracted, combined, and refined using penalizing undesirable edge patterns. This method is shown to be robuster and more general than other edge detection methods.

Optimal Protocol and Clinical Usefulness of 123 I-MIBG Cardiac Scintigraphy for Differentiation of Parkinson’s Disease and Dementia with Lewy Body from Non-Parkinson’s Diseases

천인국 대한핵의학회 2023 핵의학 분자영상 Vol.57 No.3

Purpose 123I-metaiodobenzylguanidine (MIBG) cardiac scintigraphy was a useful imaging modality for the diagnosis ofParkinson’s disease, but its diagnostic performances were variably reported. This retrospective study compared the diagnosticperformances and investigated the optimal imaging protocol of 123I-MIBG cardiac scintigraphy at various imaging timepoints in patients suspected of Parkinson’s disease in clinical practice. Methods In patients suspected of Parkinson’s disease, clinical records, autonomic function tests, and 123I-MIBG cardiacscintigraphy were retrospectively reviewed. Semi-quantitative parameters such as heart-to-mediastinum ratio (HMR) andwashout rate (WR) were calculated and compared at 15 min, 1 h, 2 h, 3 h, and 4 h post-injection (p.i.). of 123I-MIBG cardiacscintigraphy. Group A consisted of Parkinson’s disease (PD), Parkinson’s disease dementia (PDD), and dementia withLewy body (DLB), and group B consisted of non-Parkinson’s diseases such as multiple system atrophy (MSA), progressivesupranuclear palsy (PSP), drug-induced parkinsonism (DIP), essential tremor (ET), Parkinson-plus syndrome (PPS), andunspecified secondary parkinsonism (NA). The diagnostic performances of HMR and WR were compared for differentiationof group A from group B, and their clinical usefulness and optimal imaging time points were explored. Results Seventy-eight patients were included in group A (67 PD, 7 PDD, 4 DLB), and 18 patients were included in groupB (5 MSA, 3 PSP, 2 DIP, 2 ET, 1 PPS, and 1 NA). Sensitivity, specificity, accuracy, positive predictive value (PPV), andnegative predictive value of HMR and WR were maximized at 4 h p.i., (82.1%, 85.7%, 82.6%, 97.0%, and 46.2%; cutoffthreshold < 1.717; area under curve 0.8086) and at the time interval between 1 and 4 h p.i. (65.4%, 85.7%, 68.5%, 96.2%,and 30.8%; cutoff threshold > 24.1%; area under curve 0.8246), respectively, and PPVs of both HMR and WR persistentlyshowed greater than 92.7% at earlier time points and shorter time intervals. Conclusion This study reassured that 4-h-delayed imaging is recommended for the best diagnostic performances in 123I-MIBGcardiac scintigraphy. Although it showed suboptimal diagnostic performances to differentiate PD, PDD, and DLB fromnon-Parkinson’s diseases, it can be useful as an auxiliary measure for the differential diagnosis in usual clinical practice.

인터넷 경매사이트 실시간 시각화 구현

천인국 순천향대학교 부설 산업기술연구소 2002 순천향 산업기술연구소논문집 Vol.8 No.1

Internet auctions are becoming popular, because people's interest in auction markets nad technological development have worked together to implement competitive contracts as a part of electronic comerce. First we introduce an overall theory and concepts for dealing with internet auctions, next we introduce the technique and system used for internet auctions, and finally we analyze the different types of auctions and auction site. A simple auction site is developed based on the contents of the system presented. We describe the techniques used by an auction site after the auction product has been registered. We focus on auction system development as embodied in the actual conditions of sample auctions.

고속도로 통행료 자동 징수 M-Commerce 시스템의 설계 및 시뮬레이션

천인국,김문희 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.1

The purpose of this paper is to design and simulate ETC(Electronic Toll Collection system) using USIM card inside a mobile phone. It can be considered as a M-Commerce system for a electronic toll collection. The present tollgate collection system causes a car congestion. This brings about an inconvenience to drivers, to a producer high-cost, and to a nation a environment pollution and a weaken competitive power. For these problems, a high-pass system was built recently, but that needs a high-cost to set up an equipment, and is restricted to a fixed place. In this paper, we propose a M-Commerce system using mobile phone for automatic ETC. The proposed system have advantages that it needs no additional cost for setting up an equipment because most people have a mobile phone, and it has a simple payment process, and it is convenient to use

모바일 기기에서의 3차원 얼굴 표정 구현

천인국 순천향대학교 부설 산업기술연구소 2004 순천향 산업기술연구소논문집 Vol.10 No.2

Recently three dimensional computer graphics on mobile devices is being considered very important because many mobile applications such as games require three dimensional computer graphics on mobile devices. In this paper, a face implementation on mobile devices using dimensional computer graphics was studied. The face on mobile devices can be as the iconic face of caller or game character. Firstly, mobile 3D graphics technology is surveyed and the advantages and disadvantages of each method are described. Secondly, the procedure to implement three dimensional face on mobile devices is described in detail. Using Mobile3D library and 3D Studio MAX, a sample artificial face is implemented and the limit of the current implementation is discussed. The face implementation can be used as a part of RCP(Robotic Cellular Phone).

Mean Shift를 이용한 교차로 교통량 측정 시스템 개발

천인국 한국ITS학회 2008 한국ITS학회논문지 Vol.7 No.3

비디오 카메라에서 입력된 동영상을 분석하여 교차로에서 교통량을 자동적으로 측정하는 시스템을 설계, 구현하였다. 입력 영상에서 배경과 전경을 분리하기 위하여 3가지 방법을 비교 분석하였으며 이중에서 좋은 결과를 보여주는 Li의 방법을 선택하였다. 전경 영상에서 연결 성분 분석을 이용하여 각각의 블로브들을 분리하였으며 분리된 블로브들은 블로브 추적기를 이용하여 프레임 별로 추적된다. 가장 기본적인 추적기는 블로브의 크기와 위치 정보들을 이용한다. 블로브들 간에 충돌이 있는 경우에는 블로브 안의 컬러 분포를 이용하는 mean shift 알고리즘이 사용되었다. 제안된 시스템은 실제 교차로 동영상을 이용하여 테스트되었으며 휴리스틱을 추가할 경우, 좋은 감지율과 오차율을 보였다. A vehicle counting system at intersection is designed and implemented using analyzing a video stream from a camera. To separate foreground image from background, we compare three different methods, among which Li's method is chosen. Blobs are extracted from the foreground image using connected component analysis and the blobs are tracked by a blob tracker, frame by frame. The primary tracker use only the size and location of blob in foreground image. If there is a collision between blobs, the mean-shift tracking algorithm based on color distribution of blob is used. The proposed system is tested using real video data at intersection. If some huristics is applied, the system shows a good detection rate and a low error rate.