Realtime object extraction and tracking with an active camera using image mosaics

[[abstract]]Moving object extraction plays a key role in applications such as object-based videoconference, surveillance, and so on. The dimculties of moving object segmentation lie in the fact that physical objects are normally not homogeneous with to low-level features and it's usually tough to segment them accnrately and efficiently. Object segmentation based on prestored background information has proved to be effective and efficient in several applications such as videophone, video conferencing, and surveillance, etc. The previous works, however, were mainly concentrated on object segmentation with a static camera and in a stationary background. In this paper, we propose a robust and fast segmentation algorithm and a reliable tracking strategy without knowing the shape of the object in advance. The proposed system can real-time extract the foreground from the background and track the moving object with an active (pan-tilt) camera such that the moving object always stays around the center of images.[[fileno]]2030144030033[[department]]電機工程學

Survey of Error Concealment techniques: Research directions and open issues

© 2015 IEEE. Error Concealment (EC) techniques use either spatial, temporal or a combination of both types of information to recover the data lost in transmitted video. In this paper, existing EC techniques are reviewed, which are divided into three categories, namely Intra-frame EC, Inter-frame EC, and Hybrid EC techniques. We first focus on the EC techniques developed for the H.264/AVC standard. The advantages and disadvantages of these EC techniques are summarized with respect to the features in H.264. Then, the EC algorithms are also analyzed. These EC algorithms have been recently adopted in the newly introduced H.265/HEVC standard. A performance comparison between the classic EC techniques developed for H.264 and H.265 is performed in terms of the average PSNR. Lastly, open issues in the EC domain are addressed for future research consideration

Introducing New Methodologies for Identifying Design Patterns for Internationalization and Localization

This paper describes a new methodology for deriving interaction design patterns from an analysis of ethnographic data. It suggests using inductive and deductive analysis processes to identify and articulate patterns that address the needs of culturally diverse users of interactive, collaborative systems. This might inform the internationalization and localization process of computer supported collaboration systems

UNDERSTANDING INSTRUCTORS\u27 SYNCHRONOUS ONLINE COURSE DESIGN ACTIVITY

I come to this dissertation with my experiences on synchronous courses as a student and an instructional designer. Through these direct experiences I have come to realize the benefits of synchronous online courses as a course delivery format, and observed the difficulties of designing and delivering synchronous online courses. I have come to recognize the limited support of synchronous online course design. Even though there is an increased interest and use of synchronous courses, existing studies on synchronous online courses are limited, and offer little practical support to instructors about synchronous course design. The purpose of this study is to understand synchronous course design activities in order to support instructor’s effort to develop their own synchronous courses. To achieve this purpose, this dissertation looks at how five instructors design their synchronous online course with two goals: first, to identify design constraints and second, to capture the design experience and knowledge embodied in the synchronous course design cases. With a multiple case study approach, I collected data though interview, course materials and website resources about course design environments from five instructors. I analyzed the data with constant comparative method and activity system analysis. As a result, this dissertation identified various design constraints that emerged in the overall synchronous online course design process. I identified 48 design constraints and categorized those into eight categories: adaptation of synchronous course formats; converting existing face-to-face courses; instructor (designer) characteristics; learner characteristics; technology; organizational rules; environmental and cultural factors; and physical learning environments. In addition, I wrote five design cases about participants’ synchronous course design experiences. Each synchronous course design case includes information about the designer, the design situation, related design strategies, design tensions, and identified solutions to specific tensions. Specifically, I describe how the design constraints interact with one another and how interactions lead to further design tensions, and instructors’ solutions to those tensions. I will present common characteristics of synchronous course design, and implications for both designing synchronous online courses and supporting synchronous online course design at universities

Sketch-Based Interfaces to Support Collaborative Conceptual Design Learning

In order to gain a better understanding of online collaborative conceptual design processes this paper investigates how student designers make use of Lyceum, a shared virtual synchronous environment when engaged in conceptual design. The software enables users to talk to each other and share sketches when they are remotely located. The paper describes a novel methodology for observing and analysing collaborative design processes by adapting the concepts of grounded theory. Rather than concentrating on narrow aspects of the final artefacts, emerging 'themes' are generated that provide a broader picture of collaborative design process and context descriptions. Findings on the themes of 'grounding – mutual understanding' and 'support creativity' complement findings from other research, while important themes associated with 'near-synchrony' have not been emphasised in other research. From the study, a series of design recommendations are made for the development of tools to support online computer-supported collaborative work in design using a shared virtual environment