보안공학연구논문지 (Journal of Security Engineering), 제 8권 제 3호 2011년 6월 Design of Multi-camera Based Acts Monitoring System for Effective Remote Monitoring Control Ji-Hoon Lim 1), Seoksoo Kim 2) Abstract With the appearance of Pan/Tilt camera that can adjust upward & downward and right & left, fixed cameras used at the existing monitoring system are being replaced. Although the Pan/Tilt camera improves the performance of monitoring, it requires much higher cost. Therefore, there must be an alternative that produces optimum effects while utilizing the existing infrastructure. This paper designed multi-camera based acts monitoring system which enables observer to control monitoring system effectively. What was monitored will be analysed through acts when a moving object appears within the scope of many fixed cameras. Acts refer to the eyes of moving object, the pattern of moving directions, etc. and progress the detection and trace of object with video data collected. Acts also provide adaptive switching interface that help observer control remote monitoring effectively through mobile terminal. Keywords : Multi-camera, Remote Monitoring Control, Switching Interface 1. Introduction The developed camera technology which has been grafted onto various devices, allowed anyone to collect and use video data easily [1]. Video data, containing real and accurate information, is being used greatly by monitoring system. Monitoring systems are widely used at the fields, like public institutions, banks, corporates and laboratories, where security is crucial. However, as criminals at common home are increasing currently, such small field also needs monitoring system. Most monitoring systems are using fixed camera, having limited monitoring scope. So, the systems install many fixed cameras at risky area or use Pan/Tilt camera that can adjust upward & downward and right & left. Installing many cameras is inconvenient in that observer should look at many monitors separately while using Pan/Tilt camera costs a great deal. For those problems, this paper designed a monitoring system having adaptive switching interface that makes observer monitor easily, while it utilizes existing multi-camera infra Received(March 25, 2011), Review request(march 28, 2011), Review Result(1st: April 15, 2011, 2nd: April 30, 2011) Accepted(June 30, 2011) 1 306-791 Department of Multimedia Engineering, Hannam University email: siz1004@paran.com 2 (Corresponding Author) 306-791 Department of Multimedia Engineering, Hannam University, Professor email: sskim0123@naver.com * This paper has been supported by the 2011 Hannam University Research Fund. 405
Design of Multi-camera Based Acts Monitoring System for Effective Remote Monitoring Control composed of fixed cameras. The system hereof also can address, through smart phone application, the inconvenience arising from small screen based remote control monitoring. 2. Related works 2.1 Multi-camera Multi-camera is an environment in which many cameras are used. It can collect many eyed images and cover wide area. Precedent researches were mainly focused on the system to detect, recognize and trace moving objects at indoor/outdoor environment [2], and camera calibration technique for multi-camera s consistent color [3-4]. 2.2 Remote control monitoring [Fig. 1] Structure of Multi-camera Smart phone, one of mobile terminals, supports sensors, cameras, GPS and others. Through the rapid development of hardware, lots of applications are being used. This paper utilized remote control system as an smart phone application for remote control monitoring. However, the small screen of smart phone is not sufficient for effective monitoring and control. So, this paper s system provides switching interfaces proper for the situation by analyzing the acts of moving object within monitoring scope through image processing. 2.3 Object detecting and move tracing First of all, the object detecting divides background and view, and it can be broadly classified into difference image method [5] and Gaussian mixture model method [6]. Proposed monitoring system was designed based on difference image method and detects objects using the difference of brightness value of pixels at the same location from two images, which is obtained by below formula (1) and (2). After difference 406
보안공학연구논문지 (Journal of Security Engineering), 제 8권 제 3호 2011년 6월 image process like Figure 2, object can be detected more exactly through noise removal. (1) (2) [Fig. 2] Object detecting using Difference image For the tracing of detected object s moving, Kalman filter [7], which is widely used in many fields including computer vision, rocket and satellite, was used. Kalman filter removes the noise in data using existing measuring data and new measuring data and estimates new result. This paper traced and predicted object s moving by utilizing acts like object s eyes and moving directions as measuring data and, thereby, composed adaptive switching interface. 3. Acts monitoring system 3.1 System Structure Figure 3 shows the entire structure of the proposed monitoring system. The system firstly receives images from several fixed camera within monitoring system, and progresses pre-processing such as camera calibration, noise removal and light change-resistant image processing, then models background to separate background and moving object. Detected object shall be classified by identification, considering for the case of two or more objects, and be prepared for future monitoring as selected by observer. The system traces object by analyzing the object s eyes and moving directions detected in the scope of monitoring. Through them, the screen will be switched to that of the camera which facilitates effective monitoring. 407
Design of Multi-camera Based Acts Monitoring System for Effective Remote Monitoring Control 3.2 Analysis of moving object s acts [Fig. 3] Structure of Acts monitoring system Analyzing the acts of detected moving object is to predict its moving. It can be divided into eyes and directions. The moving is predicted as following Table 1. [Table 1] Prediction of moving Type eyes Moving directions Feature Predict using the direction where the face heads Predict using tiptoe as a tracing point After measuring the time a moving object looks certain direction, if the time exceeds a standard time period, the moving object is predicted to move in the relevant direction. When the moving direction is accompanied by the intervals and directions of tracing point, it can predict the time the moving object spends at relevant place, its speed and moving route. Such analysis of moving object s acts is used as an important data that makes the proposed acts monitoring system have adaptive switching interface. 3.3 Adaptive switching interface Figure 4 shows the process of adaptive switching interface which is based on object s acts analysis 408
보안공학연구논문지 (Journal of Security Engineering), 제 8권 제 3호 2011년 6월 conducted after object detecting. First figure is an assumed big indoor space where four cameras are installed at each corner, with overlapped monitoring areas. In case that it becomes difficult to monitor the precise moving of the object detected in No.1 camera s monitoring area due to certain moving, the camera screen at which observer looks will be switched to other camera screen so that observer is relieved from the burden to look at all the screen. Such adaptive switching interface is more useful in the remote control monitoring which uses mobile terminal. [Fig. 4] Switching interface in case of single object Figure 5 shows the switching interface when multi-objects are detected. In case that, during system process, an identifier is applied to detected objects and observer wishes to see the camera screen of object 2, he can select object 2 to switch the screen. [Fig. 5] Switching interface in case of multi-objects 409
Design of Multi-camera Based Acts Monitoring System for Effective Remote Monitoring Control 4. Conclusion Currently, with a sharp rise in crime, many people want to have home security system. However, there are only systems adequate for public institutions, banks, corporates and laboratories where such system is essential. In addition, those systems are very expensive. Fixed cameras in such system have limited monitoring scope, so they are being replaced with Pan/Tilt camera which can cover more wide area. This paper proposed and examined multi-camera based acts monitoring system as a solution to address the needs for personal home monitoring system and at the same time to cut down high cost with the help of existing infra. The proposed system has meaning in that user can control his home remotely and easily by the specialized interface installed in mobile terminal not in PC monitor. Future research should study the service to inform the occurrence of home invasion before user accesses the system, with judging the situation based on the proposed system. References [1] Petkovi, M., Jonker, W., "Integrated use of different content derivation techniques within a multimedia database management system", Journal of Visual Communication and Image Representation, vol. 15, pp. 303-329, 2004. [2] Black, J., Ellis, T., "Multi camera image tracking", Image and Vision Computing, vol. 24, pp. 1256-1267, 2006. [3] KaewTrakulPong, P., Bowden, R., "A real time adaptive visual surveillance system for tracking low resolution colour targets in dynamically changing scenes", Image and Vision Computing, vol. 21, issue 10, Elsevier Science Ltd, pp. 913-929, 2003. [4] Baker, P.T., Aloimonos, Y., "Calibration of a multicamera network", Computer Vision and Pattern Recognition Workshop 2003, CVPRW '03. Conference on, vol. 7, 2008. [5] Hyung-Il, C., Keun-Su, L., Yang-Weon, R., Gye-Young., "Extraction of Motion Information by Analyzing Difference Images", Proceedings of JTC-CSCC 95, pp. 189-192, 2005. [6] Stauffer, C., Grimson, W.E.L., "Adaptive Background Mixture Models for Real-Time Tracking", Computer Vision and Pattern Recognition, vol. 2, pp. 246-252, 1999. [7] Erik, C., Daniel, Z., Raul, R., "Kalman filter for vision tracking", technical report B 05-12, 2005. 410
보안공학연구논문지 (Journal of Security Engineering), 제 8권 제 3호 2011년 6월 Author Ji-Hoon Lim In 2010, he received the B.S. degree in Department of Multimedia from Hannam University, Daejeon, Korea. Now, he is working on the M.S. degree in Department of Multimedia from Hannam University. His research interests include Augmented Reality, Software Engineering, UX/UI, Context-Aware and Sensor network. Seoksoo Kim Received a B.S. degree in computer engineering from Kyungnam University, Korea, 1989, and M.S. degree in Information engineering from Sungkyun-kwan University, Korea, 1991 and Ph D. degree in Information engineering from Sungkyun-kwan University, Korea, 2002. In 2003 he joined the faculty of Hannam University, Korea where he is currently a professor in Department of Multimedia. His research interests include Multimedia Communication systems, Distance learning, Multimedia Authoring, Telemedicine, Multimedia Programming, Computer Networking. Information Security. He is a Member of KCA, KICS, KIMICS, KIPS, KMS, and DCS. 411
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