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Depth Map Compression Based on Platelet Coding and Quadratic Curve FittingWang, Han 26 October 2012 (has links)
Due to the fast development in 3D technology during recent decades, many approaches in 3D representation technologies have been proposed worldwide. In order to get an accurate information to render a 3D representation, more data need to be recorded compared to normal video sequence. In this case, how to find an efficient way to transmit the 3D representation data becomes an important part in the whole 3D representation technology. Recent years, many coding schemes based on the principle of encoding the depth have been proposed. Compared to the traditional multiview coding schemes, those new proposed schemes can achieve higher compression efficiency. Due to the development of depth capturing technology, the accuracy and quality of the reconstructed depth image also get improved. In this thesis we propose an efficient depth data compression scheme for 3D images. Our proposed depth data compression scheme is platelet based coding using Lagrangian optimization, quadtree decomposition and quadratic curve fitting. We study and improve the original platelet based coding scheme and achieve a compression improvement of 1-2 dB compared to the original platelet based scheme. The experimental results illustrate the improvement provided by our scheme. The quality of the reconstructed results of our proposed curve fitting based platelet coding scheme are better than that of the original scheme.
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Dynamical Systems and Motion VisionHeel, Joachim 01 April 1988 (has links)
In this paper we show how the theory of dynamical systems can be employed to solve problems in motion vision. In particular we develop algorithms for the recovery of dense depth maps and motion parameters using state space observers or filters. Four different dynamical models of the imaging situation are investigated and corresponding filters/ observers derived. The most powerful of these algorithms recovers depth and motion of general nature using a brightness change constraint assumption. No feature-matching preprocessor is required.
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Hiding Depth Map in JPEG Image and MPEG-2 VideoWang, Wenyi 08 November 2011 (has links)
Digital watermarking of multimedia content has been proposed as a method for different
applications such as copyright protection, content authentication, transaction
tracking and data hiding.
In this thesis, we propose a lossless watermarking approach based on Discrete Cosine
Transform (DCT) for a new application of watermarking. A depth map obtained from
a stereoscopic image pair is embedded into one of the two images using a reversible
watermarking algorithm. Different from existing approaches which hide depth map
in spatial domain, the depth information is hidden in the quantized DCT domain of
the stereo image in our method. This modification makes the watermarking algorithm
compatible with JPEG and MPEG-2 compression.
After the investigation of the quantized DCT coefficients distribution of the compressed
image and video, The bit-shift operation is utilized to embed the depth map into its associated 2D image reversibly for the purpose of achieving high compression efficiency of the watermarked image and/or video and high visual quality of stereo image and/or video after the depth map is extracted.
We implement the proposed method to analyze its performance. The experimental results show that a very high payload of watermark (e.g. depth map) can be embedded into the JPEG compressed image and MPEG-2 video. The compression efficiency is only slightly reduced after the watermark embedding and the quality of the original image or video can be restored completely at the decoder side.
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Depth Map Compression Based on Platelet Coding and Quadratic Curve FittingWang, Han 26 October 2012 (has links)
Due to the fast development in 3D technology during recent decades, many approaches in 3D representation technologies have been proposed worldwide. In order to get an accurate information to render a 3D representation, more data need to be recorded compared to normal video sequence. In this case, how to find an efficient way to transmit the 3D representation data becomes an important part in the whole 3D representation technology. Recent years, many coding schemes based on the principle of encoding the depth have been proposed. Compared to the traditional multiview coding schemes, those new proposed schemes can achieve higher compression efficiency. Due to the development of depth capturing technology, the accuracy and quality of the reconstructed depth image also get improved. In this thesis we propose an efficient depth data compression scheme for 3D images. Our proposed depth data compression scheme is platelet based coding using Lagrangian optimization, quadtree decomposition and quadratic curve fitting. We study and improve the original platelet based coding scheme and achieve a compression improvement of 1-2 dB compared to the original platelet based scheme. The experimental results illustrate the improvement provided by our scheme. The quality of the reconstructed results of our proposed curve fitting based platelet coding scheme are better than that of the original scheme.
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Hiding Depth Map in JPEG Image and MPEG-2 VideoWang, Wenyi 08 November 2011 (has links)
Digital watermarking of multimedia content has been proposed as a method for different
applications such as copyright protection, content authentication, transaction
tracking and data hiding.
In this thesis, we propose a lossless watermarking approach based on Discrete Cosine
Transform (DCT) for a new application of watermarking. A depth map obtained from
a stereoscopic image pair is embedded into one of the two images using a reversible
watermarking algorithm. Different from existing approaches which hide depth map
in spatial domain, the depth information is hidden in the quantized DCT domain of
the stereo image in our method. This modification makes the watermarking algorithm
compatible with JPEG and MPEG-2 compression.
After the investigation of the quantized DCT coefficients distribution of the compressed
image and video, The bit-shift operation is utilized to embed the depth map into its associated 2D image reversibly for the purpose of achieving high compression efficiency of the watermarked image and/or video and high visual quality of stereo image and/or video after the depth map is extracted.
We implement the proposed method to analyze its performance. The experimental results show that a very high payload of watermark (e.g. depth map) can be embedded into the JPEG compressed image and MPEG-2 video. The compression efficiency is only slightly reduced after the watermark embedding and the quality of the original image or video can be restored completely at the decoder side.
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Hiding Depth Map in JPEG Image and MPEG-2 VideoWang, Wenyi 08 November 2011 (has links)
Digital watermarking of multimedia content has been proposed as a method for different
applications such as copyright protection, content authentication, transaction
tracking and data hiding.
In this thesis, we propose a lossless watermarking approach based on Discrete Cosine
Transform (DCT) for a new application of watermarking. A depth map obtained from
a stereoscopic image pair is embedded into one of the two images using a reversible
watermarking algorithm. Different from existing approaches which hide depth map
in spatial domain, the depth information is hidden in the quantized DCT domain of
the stereo image in our method. This modification makes the watermarking algorithm
compatible with JPEG and MPEG-2 compression.
After the investigation of the quantized DCT coefficients distribution of the compressed
image and video, The bit-shift operation is utilized to embed the depth map into its associated 2D image reversibly for the purpose of achieving high compression efficiency of the watermarked image and/or video and high visual quality of stereo image and/or video after the depth map is extracted.
We implement the proposed method to analyze its performance. The experimental results show that a very high payload of watermark (e.g. depth map) can be embedded into the JPEG compressed image and MPEG-2 video. The compression efficiency is only slightly reduced after the watermark embedding and the quality of the original image or video can be restored completely at the decoder side.
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Hiding Depth Map in JPEG Image and MPEG-2 VideoWang, Wenyi January 2011 (has links)
Digital watermarking of multimedia content has been proposed as a method for different
applications such as copyright protection, content authentication, transaction
tracking and data hiding.
In this thesis, we propose a lossless watermarking approach based on Discrete Cosine
Transform (DCT) for a new application of watermarking. A depth map obtained from
a stereoscopic image pair is embedded into one of the two images using a reversible
watermarking algorithm. Different from existing approaches which hide depth map
in spatial domain, the depth information is hidden in the quantized DCT domain of
the stereo image in our method. This modification makes the watermarking algorithm
compatible with JPEG and MPEG-2 compression.
After the investigation of the quantized DCT coefficients distribution of the compressed
image and video, The bit-shift operation is utilized to embed the depth map into its associated 2D image reversibly for the purpose of achieving high compression efficiency of the watermarked image and/or video and high visual quality of stereo image and/or video after the depth map is extracted.
We implement the proposed method to analyze its performance. The experimental results show that a very high payload of watermark (e.g. depth map) can be embedded into the JPEG compressed image and MPEG-2 video. The compression efficiency is only slightly reduced after the watermark embedding and the quality of the original image or video can be restored completely at the decoder side.
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Depth Map Compression Based on Platelet Coding and Quadratic Curve FittingWang, Han January 2012 (has links)
Due to the fast development in 3D technology during recent decades, many approaches in 3D representation technologies have been proposed worldwide. In order to get an accurate information to render a 3D representation, more data need to be recorded compared to normal video sequence. In this case, how to find an efficient way to transmit the 3D representation data becomes an important part in the whole 3D representation technology. Recent years, many coding schemes based on the principle of encoding the depth have been proposed. Compared to the traditional multiview coding schemes, those new proposed schemes can achieve higher compression efficiency. Due to the development of depth capturing technology, the accuracy and quality of the reconstructed depth image also get improved. In this thesis we propose an efficient depth data compression scheme for 3D images. Our proposed depth data compression scheme is platelet based coding using Lagrangian optimization, quadtree decomposition and quadratic curve fitting. We study and improve the original platelet based coding scheme and achieve a compression improvement of 1-2 dB compared to the original platelet based scheme. The experimental results illustrate the improvement provided by our scheme. The quality of the reconstructed results of our proposed curve fitting based platelet coding scheme are better than that of the original scheme.
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Interpolation temporelle et inter-vues pour l'amélioration de l'information adjacente dans le codage vidéo distribué / Temporal and inter-view interpolation for the improvement of the side information in distributed video codingPetrazzuoli, Giovanni 14 January 2013 (has links)
Le codage de source distribué est un paradigme qui consiste à encoder indépendamment deux sources corrélées et à les décoder conjointement. Wyner et Ziv ont montré que le codage de source distribué peut atteindre les mêmes performances débit-distorsion que le codage de source conjoint, pourvu que certaines contraintes soient satisfaites. Cette caractéristique rend le codage de source distribué très attractif pour des applications qui demandent un encodeur à faible complexité ou pour ne pas être obligé à avoir des communications entre les sources. Dans le cadre du codage vidéo distribué, les trames corrélées sont encodées séparément et décodées conjointement. Dans l'architecture ainsi dite de Stanford, le flux vidéo est séparée en trames clés et Wyner-Ziv. Les trames clés sont encodées INTRA. Les trames Wyner-Ziv sont données en entrée à un codeur de canal systématique ; seulement les bits de parité sont envoyés. Au décodeur, on produit une estimation de la trame Wyner-Ziv, appelée information adjacente, en interpolant les trames clés reçues. L'information adjacente, considérée comme une version bruitée de la trame Wyner-Ziv, est corrigée par les bits de parité. Dans cette thèse, nous proposons plusieurs algorithmes pour la génération de l'information adjacente et pour l'interpolation temporelle et inter-vue. On propose aussi un algorithme de fusion bayésienne des deux interpolations. Tous les algorithmes proposés donnent des résultats meilleurs par rapport à l'état de l'art en termes de performance débit-distorsion. Nous proposons aussi plusieurs algorithmes pour l'estimation de la trame Wyner-Ziv dans le cadre de la vidéo multi-vues plus profondeur. / Distributed source coding is a paradigm that consists in encoding two correlated sources independently, provided that they are decoded jointly.Wyner and Ziv proved that distributed source coding can attain the same rate distortion performance of joint coding, under some constraints.This feature makes distributed source coding very attractive for applications that require a low-complexity encoder or for avoiding communication between the sources. In distributed video coding, correlated frames are encoded separately but decoded jointly. In the Stanford Architecture, the video is split into Key Frames and Wyner-Ziv Frames. The Key Frames are INTRA coded. The Wyner-Ziv Frames are fed into a systematic channel coder and only the parity bits are sent to the decoder. At the decoder side, an estimation of the Wyner-Ziv Frame, called side information, is produced by interpolating the available frames. The side information, that can be considered as a noisy version of the real Wyner-Ziv Frame, is corrected by the parity bits sent by the encoder. In this thesis, we propose several algorithms for side information generation both for the temporal and inter-view interpolation. We also propose a Bayesian fusion of the two estimations. All our algorithms outperform the state-of-the-art in terms of rate distortion performance. We also propose several algorithms for Wyner-Ziv estimation in the context of multiview video plus depth.
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Holoscopic 3D image depth estimation and segmentation techniquesAlazawi, Eman January 2015 (has links)
Today’s 3D imaging techniques offer significant benefits over conventional 2D imaging techniques. The presence of natural depth information in the scene affords the observer an overall improved sense of reality and naturalness. A variety of systems attempting to reach this goal have been designed by many independent research groups, such as stereoscopic and auto-stereoscopic systems. Though the images displayed by such systems tend to cause eye strain, fatigue and headaches after prolonged viewing as users are required to focus on the screen plane/accommodation to converge their eyes to a point in space in a different plane/convergence. Holoscopy is a 3D technology that targets overcoming the above limitations of current 3D technology and was recently developed at Brunel University. This work is part W4.1 of the 3D VIVANT project that is funded by the EU under the ICT program and coordinated by Dr. Aman Aggoun at Brunel University, West London, UK. The objective of the work described in this thesis is to develop estimation and segmentation techniques that are capable of estimating precise 3D depth, and are applicable for holoscopic 3D imaging system. Particular emphasis is given to the task of automatic techniques i.e. favours algorithms with broad generalisation abilities, as no constraints are placed on the setting. Algorithms that provide invariance to most appearance based variation of objects in the scene (e.g. viewpoint changes, deformable objects, presence of noise and changes in lighting). Moreover, have the ability to estimate depth information from both types of holoscopic 3D images i.e. Unidirectional and Omni-directional which gives horizontal parallax and full parallax (vertical and horizontal), respectively. The main aim of this research is to develop 3D depth estimation and 3D image segmentation techniques with great precision. In particular, emphasis on automation of thresholding techniques and cues identifications for development of robust algorithms. A method for depth-through-disparity feature analysis has been built based on the existing correlation between the pixels at a one micro-lens pitch which has been exploited to extract the viewpoint images (VPIs). The corresponding displacement among the VPIs has been exploited to estimate the depth information map via setting and extracting reliable sets of local features. ii Feature-based-point and feature-based-edge are two novel automatic thresholding techniques for detecting and extracting features that have been used in this approach. These techniques offer a solution to the problem of setting and extracting reliable features automatically to improve the performance of the depth estimation related to the generalizations, speed and quality. Due to the resolution limitation of the extracted VPIs, obtaining an accurate 3D depth map is challenging. Therefore, sub-pixel shift and integration is a novel interpolation technique that has been used in this approach to generate super-resolution VPIs. By shift and integration of a set of up-sampled low resolution VPIs, the new information contained in each viewpoint is exploited to obtain a super resolution VPI. This produces a high resolution perspective VPI with wide Field Of View (FOV). This means that the holoscopic 3D image system can be converted into a multi-view 3D image pixel format. Both depth accuracy and a fast execution time have been achieved that improved the 3D depth map. For a 3D object to be recognized the related foreground regions and depth information map needs to be identified. Two novel unsupervised segmentation methods that generate interactive depth maps from single viewpoint segmentation were developed. Both techniques offer new improvements over the existing methods due to their simple use and being fully automatic; therefore, producing the 3D depth interactive map without human interaction. The final contribution is a performance evaluation, to provide an equitable measurement for the extent of the success of the proposed techniques for foreground object segmentation, 3D depth interactive map creation and the generation of 2D super-resolution viewpoint techniques. The no-reference image quality assessment metrics and their correlation with the human perception of quality are used with the help of human participants in a subjective manner.
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