Modern holography for 3D imaging allows to reconstruct all the parallaxes that are needed for a truly immersive visualization. Nevertheless, it possesses huge amount of data which induces higher transmission and stora...
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Modern holography for 3D imaging allows to reconstruct all the parallaxes that are needed for a truly immersive visualization. Nevertheless, it possesses huge amount of data which induces higher transmission and storage requirements. To gain more popularity and acceptance, digital holography demands development of efficient coding schemes that provide significant data compression at low computation cost. Another issue that needs to be tackled when designing holography coding algorithms is interoperability with commonly used formats. In light of this, the upcoming JPEG Pleno standard aims to develop a standard framework for the representation and exchange of new imaging modalities such as holographic imaging while maintaining backward compatibility with the legacy JPEG decoders. This paper summarizes the early work on lossy compression of computer graphic holograms and analyses the efficiency of additional methods that may exhibit good satisfactory coding performance while considering the backward compatibility with legacy JPEG decoders. To validate our findings, the results of our tests are shown and interpreted. Finally, we also outline the emerging trends for future researches.
based on the classical fractal video compression method, an improved object-based stereo video compression scheme with Shape-Adaptive DCT is proposed in this paper. Firstly, we use more effective macroblock partition ...
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based on the classical fractal video compression method, an improved object-based stereo video compression scheme with Shape-Adaptive DCT is proposed in this paper. Firstly, we use more effective macroblock partition scheme instead of classical quadtree partition scheme;thus reducing the block searching strategy. The stereo fractal video coding is proposed which matches the macroblock with two reference frames in left and right view results in increasing compression ratio and reducing bit rate when transmitting compressed stereo data. The stereo codec combines the Motion Compensation Prediction (MCP) and Disparity Compensation Prediction (DCP). Fractal coding is adopted and each object is encoded independently by a prior video segmentation alpha plane, which is defined exactly as in MPEG-4. The testing results with the nature monocular and stereo video sequences provide promising performances at low bit rate coding. We believe it will be a powerful and efficient technique for the object-based monocular and stereo video sequences coding. (C) 2014 Elsevier GmbH. All rights reserved.
In this paper, we explore the fractal video sequences coding in the context of region-based functionality. Since the main drawback of fractal coding is the high computational complexity, some schemes are proposed to s...
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In this paper, we explore the fractal video sequences coding in the context of region-based functionality. Since the main drawback of fractal coding is the high computational complexity, some schemes are proposed to speed up the encoding process. As fractal encoding essentially spends most time on the search for the best-matching block in a large domain pool, this paper firstly ameliorates the conventional CPM/NCIM method and then applies a new hexagon block-matching motion estimation technology into the fractal video coding. The images in the video sequences are encoded region by region according to a previously-computed segmentation map. Experimental results indicate that the proposed algorithm spends less encoding time and achieves higher compression ratio and compression quality compared with the conventional CPM/NCIM method. (C) 2012 Elsevier Inc. All rights reserved.
Many classes of images contain spatial regions which are more important than other regions. Compression methods capable of delivering higher reconstruction quality for important parts are attractive in this situation....
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Many classes of images contain spatial regions which are more important than other regions. Compression methods capable of delivering higher reconstruction quality for important parts are attractive in this situation. For medical images, only a small portion of the image might be diagnostically useful, but the cost of a wrong interpretation is high. Hence, regionbasedcoding (RBC) technique is significant for medical image compression and transmission. Loss less compression schemes with secure transmission play a key role in telemedicine applications that help in accurate diagnosis and research. In this paper, we propose lossless scalable RBC for Digital Imaging and Communications in Medicine (DICOM) images based on Integer Wavelet Transform (IWT) and with distortion limiting compression technique for other regions in image. The main objective of this work is to reject the noisy background and reconstruct the image portions losslessly. The compressed image can be accessed and sent over telemedicine network using personal digital assistance (PDA) like mobile.
A novel video sequence compression scheme is proposed in order to realize the efficient and economical transmission of video sequence, and also the region-based functionality of MPEG-4. The CPM and NCIM fractal coding...
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ISBN:
(纸本)9780819473622
A novel video sequence compression scheme is proposed in order to realize the efficient and economical transmission of video sequence, and also the region-based functionality of MPEG-4. The CPM and NCIM fractal coding scheme is applied on each region independently by a prior image segmentation map (alpha plane) which is exactly the same as defined in MPEG-4. The first n frames of video sequence are encoded as a "set" using the Circular Prediction Mapping (CPM) and encode the remaining frames using the Non Contractive Interframe Mapping (NCIM). The CPM and NCIM accomplish the motion estimation and compensation, which can exploit the high temporal correlations between the adjacent frames of video sequence. The experimental results with the monocular video sequences provide promising performances at low bit rate coding, such as the application in video conference. We believe the proposed fractal video codec will be a powerful and efficient technique for the region-based video sequence coding.
region-based encoding techniques have been long investigated for the compression of still images and video sequences and have recently gained much popularity, as testified by the object-based nature of the MPEG-4 vide...
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ISBN:
(纸本)0780391349
region-based encoding techniques have been long investigated for the compression of still images and video sequences and have recently gained much popularity, as testified by the object-based nature of the MPEG-4 video coding standard. This work aims at analyzing costs and advantages of implementing such an approach by shape-adaptive wavelet transform and shape-adaptive SPIHT. The analysis of several performance measures in a number of experiments confirm the potential of wavelet-basedregion-based approach, and provide insight about what performance gains and losses can be expected in various operative conditions.
This paper proposes a fast segmentation method for still image based on a hybrid of clustering and morphological segmentation approach. The objective of the clustering is to partition an input image into a number of c...
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This paper proposes a fast segmentation method for still image based on a hybrid of clustering and morphological segmentation approach. The objective of the clustering is to partition an input image into a number of clusters such that the gray levels within each cluster are similar. The clustered image is further processed by using morphological segmentation approach, in which a seeded region growing however plays a role of the decision tool instead of a watershed algorithm for a remarkable improvement of processing time. The performance of the proposed method is evaluated by comparing its region-based coding results with those of the morphological watershed-based segmentation method and the split-and-merge algorithm. The experiments results showed that region-based coding using the proposed algorithm yields PSNR improvement of about 1.5 dB over the morphological watershed-based method. Especially, the total time elapsed to segment an image using the proposed method is reduced about 1/6 and 1/3 compared with those of the watershed-based segmentation and the split-and-merge methods, respectively.
Compression of remote-sensing images can be necessary in various stages of the image life, and especially on-board a satellite before transmission to the ground station. Although on-board CPU power is quite limited, i...
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Compression of remote-sensing images can be necessary in various stages of the image life, and especially on-board a satellite before transmission to the ground station. Although on-board CPU power is quite limited, it is now possible to implement sophisticated real-time compression techniques, provided that complexity constraints are taken into account at design time. In this paper we consider the class-based multispectral image coder originally proposed in [Gelli and Poggi, Compression of multispectral images by spectral classification and transform coding, IEEE Trans. Image Process. (April 1999) 476-489 [5]] and modify it to allow its use in real time with limited hardware resources. Experiments carried out on several multispectral images show that the resulting unsupervised coder has a fully acceptable complexity, and a rate-distortion performance which is superior to that of the original supervised coder, and comparable to that of the best coders known in the literature. (C) 2006 Elsevier B.V. All rights reserved.
region-based video coding schemes employed in MPEG-4 are also promising for still image coding applications where images contain a number of objects that can be encoded at different bit rates, such as compression of m...
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region-based video coding schemes employed in MPEG-4 are also promising for still image coding applications where images contain a number of objects that can be encoded at different bit rates, such as compression of medical images for archiving and transmission. Motivated by this fact, in this letter we investigate multiregion multiquality (MRMQ) coding with quadtree-based wavelet coders. We present a novel scheme which addresses the region size sensitivity problem in region-based coding. The proposed method outperforms the region-of-interest (ROI) coding unit of JPEG-2000;it is possible to save 0.3 bits per pixel to attain the same ROI/background fidelity without sacrificing the additional features provided by JPEG-2000, such as resolution scalability and error resilience.
The wide usage of small satellite imagery, especially its commercialization, makes data-based onboard compression not only meaningful but also necessary in order to solve the bottleneck between the huge volume of data...
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The wide usage of small satellite imagery, especially its commercialization, makes data-based onboard compression not only meaningful but also necessary in order to solve the bottleneck between the huge volume of data generated onboard and the very limited downlink bandwidth. In this paper, we propose a method that encodes different regions with different algorithms. We use three shape-adaptive image compression algorithms as the candidates. The first one is a JPEG-based algorithm, the second one is based on the object-based wavelet transform (OWT) method proposed by [1], and the third adopts Hilbert scanning of the regions of interest followed by one-dimensional (1-D) wavelet transform. The three algorithms are also applied to the full image so that we can compare their performance on a whole rectangular image. We use eight Landsat Th I multispectral images and another 12 small satellite single-band images as our data set. The results show that these compression algorithms have significantly different performance for different regions. For relatively smooth regions, e.g., regions that consist of a single type of vegetation or water areas etc, the 1-D wavelet method is the best. For highly textured regions, e.g., urban areas, mountain areas, and so on, the modified OWT method wins over the others. For the whole image, OWT working at whole image mode, which is just an ordinary 2-D wavelet compression, is the heat. based on this, we propose a new data-based compression architecture that extracts particular regions according to the application of interest and then involves different algorithms to encode different regions in order to achieve better performance than traditional onboard compression schemes in which a fixed compression method is applied to the whole image no matter what the application is. This approach is most appropriate for use with images captured by microsatellites, which are commissioned for specific applications in which one knows a priori which cla
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