22,836 research outputs found

    Efficient Coding of Shape and Transparency for Video Objects

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    A robust motion estimation and segmentation approach to represent moving images with layers

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    The paper provides a robust representation of moving images based on layers. To that goal, we have designed efficient motion estimation and segmentation techniques by affine model fitting suitable for the construction of layers. Layered representations, originally introduced by Wang and Adelson (see IEEE Transactions on Image Processing, vol.3, no.5, p.625-38, 1994) are important in several applications. In particular they are very appropriate for object tracking, object manipulation and content-based scalability which are among the main functionalities of the future MPEG-4 standard. In addition a variety of examples are provided that give a deep insight into the performance bounds of the representation of moving images using layers.Peer ReviewedPostprint (published version

    Coding Transparency in Object-Based Video

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    Detection of dirt impairments from archived film sequences : survey and evaluations

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    Film dirt is the most commonly encountered artifact in archive restoration applications. Since dirt usually appears as a temporally impulsive event, motion-compensated interframe processing is widely applied for its detection. However, motion-compensated prediction requires a high degree of complexity and can be unreliable when motion estimation fails. Consequently, many techniques using spatial or spatiotemporal filtering without motion were also been proposed as alternatives. A comprehensive survey and evaluation of existing methods is presented, in which both qualitative and quantitative performances are compared in terms of accuracy, robustness, and complexity. After analyzing these algorithms and identifying their limitations, we conclude with guidance in choosing from these algorithms and promising directions for future research

    Optimized mobile thin clients through a MPEG-4 BiFS semantic remote display framework

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    According to the thin client computing principle, the user interface is physically separated from the application logic. In practice only a viewer component is executed on the client device, rendering the display updates received from the distant application server and capturing the user interaction. Existing remote display frameworks are not optimized to encode the complex scenes of modern applications, which are composed of objects with very diverse graphical characteristics. In order to tackle this challenge, we propose to transfer to the client, in addition to the binary encoded objects, semantic information about the characteristics of each object. Through this semantic knowledge, the client is enabled to react autonomously on user input and does not have to wait for the display update from the server. Resulting in a reduction of the interaction latency and a mitigation of the bursty remote display traffic pattern, the presented framework is of particular interest in a wireless context, where the bandwidth is limited and expensive. In this paper, we describe a generic architecture of a semantic remote display framework. Furthermore, we have developed a prototype using the MPEG-4 Binary Format for Scenes to convey the semantic information to the client. We experimentally compare the bandwidth consumption of MPEG-4 BiFS with existing, non-semantic, remote display frameworks. In a text editing scenario, we realize an average reduction of 23% of the data peaks that are observed in remote display protocol traffic

    Digital Image Access & Retrieval

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    The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio

    Context based Coding of Quantized Alpha Planes for Video Objects

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    Understanding Visual Feedback in Large-Display Touchless Interactions: An Exploratory Study

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    Touchless interactions synthesize input and output from physically disconnected motor and display spaces without any haptic feedback. In the absence of any haptic feedback, touchless interactions primarily rely on visual cues, but properties of visual feedback remain unexplored. This paper systematically investigates how large-display touchless interactions are affected by (1) types of visual feedback—discrete, partial, and continuous; (2) alternative forms of touchless cursors; (3) approaches to visualize target-selection; and (4) persistent visual cues to support out-of-range and drag-and-drop gestures. Results suggest that continuous was more effective than partial visual feedback; users disliked opaque cursors, and efficiency did not increase when cursors were larger than display artifacts’ size. Semantic visual feedback located at the display border improved users’ efficiency to return within the display range; however, the path of movement echoed in drag-and-drop operations decreased efficiency. Our findings contribute key ingredients to design suitable visual feedback for large-display touchless environments.This work was partially supported by an IUPUI Research Support Funds Grant (RSFG)

    Utility of a scanning densitometer in analyzing remotely sensed imagery

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    The utility of a scanning densitometer for analyzing imagery in the NASA Lewis Research Center's regional remote sensing program was evaluated. Uses studied include: (1) quick-look screening of imagery by means of density slicing, magnification, color coding, and edge enhancement; (2) preliminary category classification of both low- and high-resolution data bases; and (3) quantitative measurement of the extent of features within selected areas. The densitometer was capable of providing fast, convenient, and relatively inexpensive preliminary analysis of aerial and satellite photography and scanner imagery involving land cover, water quality, strip mining, and energy conservation
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