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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Energy Calibration of Different Modes of a pn-CCD-camera on board the X-Ray Observatory XMM-Newton

Winroth, Gustaf January 2007 (has links)
<p>The X-ray Multi-mirror Mission, XMM-Newton was launched by the European Space Agency, ESA, in 1999. XMM-Newton carries six cameras, including a silicon pn-junction Charge Coupled Device, or pn-CCD camera. This camera has six operating modes, spatially as well as time resolved. The main objective of this project is to refine the Burst mode energy correction in order to align the measured energy spectra observed in the Burst mode with the spectra taken in the Full Frame mode. An observation of the line-rich supernova remnant called Cassiopeia A is used to evaluate the line positions in each mode such that the energy correction function used for the alignment can be modified accordingly. The analysis further treats the application of the correction on a source with a continuous spectrum, the Crab nebula. Discussion shows how to reduce eventual residuals in the Crab spectrum by modifying the correction function while keeping the alignment of the Cas-A spectra. The final product is an update of the corresponding published calibration file.</p>
2

Energy Calibration of Different Modes of a pn-CCD-camera on board the X-Ray Observatory XMM-Newton

Winroth, Gustaf January 2007 (has links)
The X-ray Multi-mirror Mission, XMM-Newton was launched by the European Space Agency, ESA, in 1999. XMM-Newton carries six cameras, including a silicon pn-junction Charge Coupled Device, or pn-CCD camera. This camera has six operating modes, spatially as well as time resolved. The main objective of this project is to refine the Burst mode energy correction in order to align the measured energy spectra observed in the Burst mode with the spectra taken in the Full Frame mode. An observation of the line-rich supernova remnant called Cassiopeia A is used to evaluate the line positions in each mode such that the energy correction function used for the alignment can be modified accordingly. The analysis further treats the application of the correction on a source with a continuous spectrum, the Crab nebula. Discussion shows how to reduce eventual residuals in the Crab spectrum by modifying the correction function while keeping the alignment of the Cas-A spectra. The final product is an update of the corresponding published calibration file.
3

A Hybrid Approach For Full Frame Loss Concealment Of Multiview Video

Bilen, Cagdas 01 August 2007 (has links) (PDF)
Multiview video is one of the emerging research areas especially among the video coding community. Transmission of multiview video over an error prone network is possible with efficient compression of these videos. But along with the studies for efficiently compressing the multiview video, new error concealment and error protection methods are also necessary to overcome the problems due to erroneous channel conditions in practical applications. In packet switching networks, packet losses may lead to block losses in a frame or the loss of an entire frame in an encoded video sequence. In recent years several algorithms are proposed to handle the loss of an entire frame efficiently. However methods for full frame losses in stereoscopic or multiview videos are limited in the literature. In this thesis a stereoscopic approach for full frame loss concealment of multiview video is proposed. In the proposed methods, the redundancy and disparity between the views and motion information between the previously decoded frames are used to estimate the lost frame. Even though multiview video can be composed of more than two views, at most three view are utilized for concealment. The performance of the proposed algorithms are tested against monoscopic methods and the conditions under which the proposed methods are superior are investigated. The proposed algorithms are applied to both stereoscopic and multiview video.
4

Error Concealment In 3d Video

Aydogmus, Sercan 01 December 2011 (has links) (PDF)
The advances in multimedia technologies increased the interest in utilizing three dimensional (3D) video applications in mobile devices. However, wireless transmission is significantly prone to errors. Typically, packets may be corrupted or lost due to transmission errors, causing blocking artifacts. Furthermore, because of compression and coding, the error propagates through the sequence and salient features of the video cannot be recovered until a key-frame or synchronization-frame is correctly received. Without the use of concealment and enhancement techniques, visible artifacts would inevitably and regularly appear in the decoded stream. In this thesis, error concealment techniques for full frame losses in depth plus video and stereo video structures are implemented and compared. Temporal and interview correlations are utilized to predict the lost frames while considering the memory usage and computational complexity.The concealment methods are implemented on jm17.2 decoder which is based on H.264/AVC specifications [1]. The simulation results are compared with the simple frame copy (FC) method for different sequences having different characteristics.

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