In a recent work, the author proposed to study the performance of still image quality indices such as the SSIM by using them as objective function of rate allocation algorithms. The outcome of that work was not only a...
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In a recent work, the author proposed to study the performance of still image quality indices such as the SSIM by using them as objective function of rate allocation algorithms. The outcome of that work was not only a multi-scale SSIM optimal JPEG 2000 implementation, but also a first-order approximation of the MS-SSIM that is surprisingly similar to more traditional contrast-sensitivity and visual masking based approaches. It will be seen in this work that the only difference between the latter works and the MS-SSIM index is the choice of the exponent of the masking term, and furthermore, that a slight modification of the SSIM definition reproducing the traditional exponent is able to improve the performance of the index at or below the visual threshold. It is hence demonstrated that the duality of quality indices and rate allocation helps to improve both the visual performance of the compression codec and the performance of the index.
In this paper, we propose a new image quality metric using derivative filters in the context of compressive sensing (CS) that represents a sparse or compressible signal with a small number of measurements. In general,...
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In this paper, we propose a new image quality metric using derivative filters in the context of compressive sensing (CS) that represents a sparse or compressible signal with a small number of measurements. In general, an arbitrary image is not sparse or compressible, however, its derivative image is compressible. In this paper, derivative images are obtained using first- and second-order derivative filters such as Sobel operators and Laplacian of Gaussian filters. Each derivative image of the reference and distorted images is measured via CS. Measurements of derivative images are compared for evaluating the image quality. Experiments with the laboratory for image and video engineering database show the effectiveness of the proposed method.
The authors have recently introduced the JPEG2000-Based Scalable Interactive Video (JSIV) paradigm. JSIV relies on JPEG2000 format for providing scalability and accessibility, and on motion compensation and conditiona...
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The authors have recently introduced the JPEG2000-Based Scalable Interactive Video (JSIV) paradigm. JSIV relies on JPEG2000 format for providing scalability and accessibility, and on motion compensation and conditional replenishment to exploit temporal redundancy. JSIV can provide considerably better interactivity compared to existing video streaming practices, and can adapt immediately to interactive changes in client interests, such as forward or backward playback and zooming into individual frames. This work extends our previous work by providing server and client policies that can exploit the client's knowledge about the quantization intervals of received samples in selecting a favorable predictor in dyadic hierarchical B-frame arrangement that does not employ motion compensation. We also demonstrate the flexibility of the JSIV paradigm by showing an improved client policy working with a non-improved server policy without any negative impact on reconstructed video.
Numerous Image Quality Measures (IQMs) have been proposed in the literature. While some are based on structural analysis of images, others rely on the characteristics (or limitations) of the Human Visual System (HVS)....
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Numerous Image Quality Measures (IQMs) have been proposed in the literature. While some are based on structural analysis of images, others rely on the characteristics (or limitations) of the Human Visual System (HVS). However, none of the existing IQMs is shown to be robust across all types of degradations. Indeed, some IQMs are more efficient for a given artifact (such as blurring or blocking) but inefficient for others. In this paper, we propose to circumvent this limitation by adding a preprocessing step before measuring image quality. We propose to detect the type of the degradation contained in the image, then use the most "relevant" IQM for that specific type of degradation. The classification of different degradations is performed using simple Linear Discriminant Analysis (LDA). The performance of the proposed method is evaluated in terms of classification accuracy across different types of degradations and shown to outperform different IQMs when used independently of the degradation type.
Nowadays, the design flow of complex signal processing embedded systems starts with a specification of the application by means of a large and sequential program (usually in C/C++). As we are entering in the multicore...
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Nowadays, the design flow of complex signal processing embedded systems starts with a specification of the application by means of a large and sequential program (usually in C/C++). As we are entering in the multicore era, sequential programs are no longer the most appropriate way to specify algorithms targeted to run on several processing units. The new ISO/MPEG Reconfigurable Video coding (RVC) standard is proposing a new paradigm for specifying and designing complex signal processing systems. The RVC standard enables specifying new codecs by assembling blocks, or so called Functional Units (FUs) from a standard Video Tool Library (VTL). Flexibility, reusability, and modularity are the key features of RVC. This new way of specifying algorithms clearly simplifies the task of designing future video coding applications by allowing software and hardware reuse across multiple video coding standards. Specifications are provided in the form of an actor and dataflow-based language called CAL. Although the RVC standard does not imply any specific implementation design flow, it is an appropriate starting point for targeting multiple processing units platforms. This paper describes a new model-driven design flow which considers both algorithm and architecture to map RVC codec specifications onto heterogeneous and multi-core systems.
With the development of Internet and multimedia technologies, multimedia copyright protection and content authentication have become serious problems that need to be solved urgently. Digital watermarking has been rega...
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With the development of Internet and multimedia technologies, multimedia copyright protection and content authentication have become serious problems that need to be solved urgently. Digital watermarking has been regarded as an effective solution to protect various kinds of digital contents against illegal use. In this paper, a hybrid watermarking technique which combines the discrete cosine transformation (DCT) and singular value decomposition (SVD) is presented. We give the experimental results of the proposed technique against some attacks.
In this paper we present main parameters of the ringing artefact and demonstrate their influence on image fidelity of lossy compressed images. We apply variations of these parameters to create a specific set of test i...
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In this paper we present main parameters of the ringing artefact and demonstrate their influence on image fidelity of lossy compressed images. We apply variations of these parameters to create a specific set of test images to highlight the ringing artefact and to be able to evaluate the behaviour of ringing along edges. Therefore we introduce a new ringing metric, that analyzes image profiles of compressed images in terms of global luminance shift, blur and ringing.
Several algorithms for global motion estimation in video sequences using pixel- or block-based approaches have been published. Most known pixel-based methods lack in performance while when using block-based algorithms...
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Several algorithms for global motion estimation in video sequences using pixel- or block-based approaches have been published. Most known pixel-based methods lack in performance while when using block-based algorithms working on motion vectors, robustness to outliers and accuracy is missing. In this paper we present the fundamentals of a significantly improved, robust block-based method for global motion estimation in compressed domain following the generic Helmholtz principle. To this aim, we use motion vector fields as provided by MPEG data streams. Background PSNR values for four motion compensated test sequences show that our new method delivers results comparable to more complex algorithms.
In this work we introduce a new algorithm for color image compression based on inter-color correlations of the RGB (red, green and blue) primary colors of images and video. We employ the Bayer pattern, widely used in ...
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In this work we introduce a new algorithm for color image compression based on inter-color correlations of the RGB (red, green and blue) primary colors of images and video. We employ the Bayer pattern, widely used in digital cameras and mobile phones, for its compression software. Our proposed method outperforms JPEG2000 for all the images tested, with a gain of more than 1dB in peak signal-to-noise ratio (PSNR) on average. Our conclusion is that the new algorithm could be useful in efficient visual communication.
Focus on the image compressing problem of unmanned aerial vehicle with high compression ratio, fixed compressing ratio and low computational complexity requirement, a low-complexity image-sequence compressing algorith...
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Focus on the image compressing problem of unmanned aerial vehicle with high compression ratio, fixed compressing ratio and low computational complexity requirement, a low-complexity image-sequence compressing algorithm based on homography transformation was proposed. The image sequences were dynamically divided into frame-groups according the data from airborne inertial navigation systems, and the intermediate frames in the same frame-group was b i-directionally predicted by the first-frame and the end-frame with homography transformation. The homography matrix was got approximately by the airborne inertial navigation systems firstly and then was accurately computed by fast multiple sub-areas template matching. At the end the first frame and the residual images of the intermediate frames of the same frame-group was merged into a big image and coded by JPEG2000 to generate fixed-size code streams. The experiment results show that the proposed algorithm was with high compression performance, low computational complexity and excellent capacity for code-size control and will has good prospect in engineer.
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