• 한국의학물리학회지:의학물리
• /
• 제19권3호
• /
• pp.143-149
• /
• 2008

본 연구의 목적은 디지털 방사선 흉부영상의 개선을 위한 영상처리방법을 제안하고 임상적 유용성을 평가하는 것이다. 흉부영상의 edge를 보존하면서 산란성 노이즈 제거를 위한 비선형의 반복 필터가 고안되었다. 영상의 다이나믹 레인지 (dynamic_range)의 조절이 이루어 졌으며, 해부학적 영역과 주변픽셀과의 호환성을 바탕으로 적응적 영상증강이 이루어졌다. 종격동 영역에서의 영상증강과 더불어, 폐 영역에서의 혈관조직, 기관지, 폐 조직 등이 적절하게 증강되었다. 3명의 판독의에 의한 임상평가가 이루어 졌으며, PA 영상에서는 11개, 그리고 Lateral 영상에서는 9개의 해부학적 영역이 면밀하게 관찰되었다. 각각 100장의 영상들이 ITU (International Telecommunication Union) recommendation 500에 따라 평가되어졌으며, 그 결과는 good과 adequate중간인 3.4의 평균치를 보였다. 이는 제안한 영상처리의 임상적 유용성이 최소한 양호함 이상의 가치가 있음을 의미한다. 유용한 해부학적 정보의 손실을 방지하기 위해, 영상표시장치와 인간의 인지계를 고려하면서 영상개선이 이루어졌다. 디지털 방사선기기의 등장으로 진단의 정확성을 향상시키기 위한 지속적인 영상 개선연구가 필요하다.

• Journal of Biosystems Engineering
• /
• 제26권1호
• /
• pp.21-28
• /
• 2001

Major deficiencies of current automation scheme including various robots for bioproduction include the lack of task adaptability and real time processing, low job performance for diverse tasks, and the lack of robustness of take results, high system cost, failure of the credit from the operator, and so on. This paper proposed a scheme that could solve the current limitation of task abilities of conventional computer controlled automatic system. The proposed scheme is the man-machine hybrid automation via tele-operation which can handle various bioproduction processes. And it was classified into two categories. One category was the efficient task sharing between operator and CCM(computer controlled machine). The other was the efficient interface between operator and CCM. To realize the proposed concept, task of the object identification and extraction of 3D coordinate of an object was selected. 3D coordinate information was obtained from camera calibration using camera as a measurement device. Two stereo images were obtained by moving a camera certain distance in horizontal direction normal to focal axis and by acquiring two images at different locations. Transformation matrix for camera calibration was obtained via least square error approach using specified 6 known pairs of data points in 2D image and 3D world space. 3D world coordinate was obtained from two sets of image pixel coordinates of both camera images with calibrated transformation matrix. As an interface system between operator and CCM, a touch pad screen mounted on the monitor and remotely captured imaging system were used. Object indication was done by the operator’s finger touch to the captured image using the touch pad screen. A certain size of local image processing area was specified after the touch was made. And image processing was performed with the specified local area to extract desired features of the object. An MS Windows based interface software was developed using Visual C++6.0. The software was developed with four modules such as remote image acquisiton module, task command module, local image processing module and 3D coordinate extraction module. Proposed scheme shoed the feasibility of real time processing, robust and precise object identification, and adaptability of various job and environments though selected sample tasks.

• 지능정보연구
• /
• 제13권1호
• /
• pp.1-14
• /
• 2007

휴대전화의 배경화면을 위한 캐릭터 이미지의 수요가 모바일 컨텐츠 시장에서 빠르게 성장함에도 불구하고 지능형 검색 도구의 부재로 인해 사용자들은 원하는 이미지를 검색하는 데 많은 어려움을 겪고 있다. 이 문제를 해결하기 위한 방법으로 이미지 검색을 위해 가장 널리 사용되는 내용기반 이미지 검색(Content-Based Image Retrieval; CBIR)이 사용될 수 있겠으나 PC-기반 시스템과는 달리 초기 질의 요구를 만족시킬 수 없는 모바일 응용 소프트웨어의 제약 사항의 극복이 필요하다. 본 연구에서는 적합성 피드백과정에서 얻어진 선호도 정보를 이용하는 협업필터링(Collaborative Filtering; CF) 기법을 사용하여 내용기반 이미지 검색의 초기 질의로 사용될 수 있는 후보이미지의 리스트를 자동 생성하는 IQS-AutoGen이라고 하는 새로운 방법을 제안한다. IQS-AutoGen은 CBIR로부터 피드백된 이미지들에 대한 적합성 정보를 이용하여 목표 사용자와 선호도가 유사한 이웃(neighbor)을 확인하고 이웃들이 선호하는 이미지들의 리스트를 제공하는 CF 프로세스를 통해 CBIR을 위한 초기 질의 집합(Initial Query Set : IQS)을 자동으로 생성한다. 따라서 모바일 사용자는 IQS에 있는 이미지들 중의 하나를 선택하여 CBIR 세션을 위한 질의 이미지로 사용할 수 있게 된다. PC-기반 프로토타입 시스템을 사용하여 실험한 결과로부터 제안한 방법이 모바일 인터넷 환경에서 CBIR의 초기질의 요구를 성공적으로 만족시킬 뿐만 아니라 현재의 검색 방법보다 우수한 성능을 보여주고 있음을 알 수 있다.

• Journal of Computing Science and Engineering
• /
• 제2권1호
• /
• pp.98-108
• /
• 2008

Terrain reconstruction from images is an ill-posed, yet commonly desired Structure from Motion task when compositing visual effects into live-action photography. These surfaces are required for choreography of a scene, casting physically accurate shadows of CG elements, and occlusions. We present a novel framework for generating the geometry of landscapes from extremely noisy point cloud datasets obtained via limited resolution techniques, particularly optical flow based vision algorithms applied to live-action video plates. Our contribution is a new statistical approach to remove erroneous tracks ('outliers') by employing a unique combination of well established techniques-including Gaussian Mixture Models (GMMs) for robust parameter estimation and Radial Basis Functions (REFs) for scattered data interpolation-to exploit the natural constraints of this problem. Our algorithm offsets the tremendously laborious task of modeling these landscapes by hand, automatically generating a visually consistent, camera position dependent, thin-shell surface mesh within seconds for a typical tracking shot.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
• /
• pp.231-234
• /
• 2001

In this paper, we present a robust watermarking technique based on a DCT-domain watermarking approach and an order statistic(OS) filter. The proposed technique inserts one watermark into each of four coefficients within a 2 ${\times}$ 2 block which is scanned on DCT coefficients in the zig-zag ordering from the medium frequency range. The detection algorithm uses an adaptive trimmed mean operator as a local estimator of the embedded watermark to obtain the desired robustness in the presence of additive Gaussian noise and JPEG compression attacks. The performance is analyzed through statistical analysis and numerical experiments. It is shown that the robustness properties against additive noise and JPEG compression attacks are more enhanced than the previous techniques.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.408-410
• /
• 2003

In this paper, an improved gradient direction assisted linking algorithm is proposed. This algorithm begins with initial seeds satisfying some local criteria. Then it will search along the direction provided by the initial point. A window will be generated in the gradient direction of the current point. Instead of the conventional method which only considers the value of the local salient structure, an improved mathematical model is proposed to describe the desired linear features. This model not only considers the value of the salient structure but also the direction of it. Furthermore, the linking problem under this model can be efficiently solved by dynamic programming method. This algorithm is tested for linear features detection in IKONOS images. The result demonstrates this algorithm is quite promising.

• 한국정밀공학회지
• /
• 제16권2호통권95호
• /
• pp.68-73
• /
• 1999

Generally, most of machining processes are done according to the dimention of the draft made by CAD. However, there are many cases that a sample is given without the draft because of the simplicity of the shape in the machining of 2D objects. To cut the same shape as the given sample, this paper proposes the method to extract the geometric information about a large sample using the robot vision and to draw the demensional draft for the machining. Because the resolution of one frame in the vision system is too low, it is necessary to set up a camera according to the desired resolution and to capture the image moving along the contour. And the overall outline can be compounded of the sequentially captured images. In the experiment, we compared the product after the cutting with the original sample and found that the size of two objects was coincided within the allowed error bound.

• 한국산업정보학회논문지
• /
• 제19권1호
• /
• pp.69-75
• /
• 2014

오디오 스테가노그래피는 새로운 비밀통신 기술로서 발전한 은닉메시지를 기록하는 과학이며 예술이다. 그리고 오디오 스테가노그래피는 이진화 된 메시지를 이미지의 8번째 LSB 층에 숨기는 과정과 유사하다. 효과적인 스테가노그래픽 기법은 비밀자료를 많이 숨기고, 감지할 수 없게 하는 것이다. 이 논문에서는 외부적 공격으로부터 비밀 메시지를 안전하게 숨기기 위해 재배열 순서키와 수정된 LSB 기법에 의한 방법을 제안한다.

• 한국경영과학회지
• /
• 제29권4호
• /
• pp.11-40
• /
• 2004

Organizations have attempted to develop Knowledge Management Systems for achieving competitive advantage by effectively managing organizational knowledge. However, if Knowledge Management Systems are not user-oriented, organizations may not attain desired goals. That is, it must be utilized and accepted by organizational members to be successful systems. This study proposes an extended Technology Acceptance Model and empirically validates it. For that purpose, a research model is set UP that consists of antecedent variables, perception moderators, and intention to use the system. Empirical data analysis found significant relationships among research variables, as suggested in research hypotheses. The results of the analysis indicated that perceived usefulness, ease of use, job relevance and information quality should be considered as important factors in designing Knowledge Management Systems. In addition, perceived value, incentive, affect, self-efficacy, and image were found to influence the perception of users in the usage situation.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
• /
• pp.566-571
• /
• 1994

This paper presents in image-based visual servo control scheme for tracking a workpiece with a hand-eye coordinated robotic system using the fuzzy-neural-network. The goal is to control the relative position and orientation between the end-effector and a moving workpiece using a single camera mounted on the end-effector of robot manipulator. We developed a fuzzy-neural-network that consists of a network-model fuzzy system and supervised learning rules. Fuzzy-neural-network is applied to approximate the nonlinear mapping which transforms the features and theire change into the desired camera motion. In addition a control strategy for real-time relative motion control based on this approximation is presented. Computer simulation results are illustrated to show the effectiveness of the fuzzy-neural-network method for visual servoing of robot manipulator.