This paper deals with the blockwise disparity map estimation problem for stereoscopic image coding. Generally, disparities are selected amongst a search area by minimizing a local distortion. In addition the larger th...
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ISBN:
(纸本)9781509027811
This paper deals with the blockwise disparity map estimation problem for stereoscopic image coding. Generally, disparities are selected amongst a search area by minimizing a local distortion. In addition the larger the search area is, the more often a better disparity can be chosen and the lower the global distortion is. However, the resulting disparity map containing higher number of different disparities is encoded with a larger bitrate. This paper proposes two approaches to take advantage of large search areas while reducing not only the bitrate of the estimated disparity map but also the computational complexity of the optimal solution. The developed sub-optimal algorithms rely on the initial set of disparities selected by the traditional block-matching algorithm (BMA) to compute new sets minimizing the distortion of the predicted view under a bitrate constraint. Simulation results confirm the benefits of our algorithms compared to the BMA in terms of bitrate-distortion.
Motion estimation from a video sequence is an interesting issue in video processing. Nowadays, research has been focused on global optimization techniques, that estimate the optical flow for pixel neighborhoods. In th...
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Motion estimation from a video sequence is an interesting issue in video processing. Nowadays, research has been focused on global optimization techniques, that estimate the optical flow for pixel neighborhoods. In this paper, a hybrid statistically effective motion estimation procedure has been proposed for better effectiveness video compression. This method explores by utilizing a hexagonal search pattern with a secure number of search points at every lattice. It uses the association among bordering pixels within the frame. So as to diminish the computative intricacy, this methodology uses hybrid hexagon search and teaching-learning based optimization algorithm. This method additionally decreases the computational unpredictability of blockmatching procedure. The image quality has been confirmed through 3D reconstruction using structured light techniques. This strategy has been contrasted with different existing strategies and hereby utilizing the hexagon search-based teaching-learning optimization algorithm could get a higher precision interms of PSNR of 44.36%, MSE of 2.40 and compression ratio of 7.50.
This paper proposes a rate-based candidate elimination strategy for Motion Estimation, which is considered one of the main sources of encoder complexity. We build from findings of previous works that show that selecte...
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ISBN:
(纸本)9781728176055
This paper proposes a rate-based candidate elimination strategy for Motion Estimation, which is considered one of the main sources of encoder complexity. We build from findings of previous works that show that selected motion vectors are generally near the predictor to propose a solution that uses the motion vector bitrate to constrain the candidate search to a subset of the original search window, resulting in less distortion computations. The proposed method is not tied to a particular search pattern, which makes it applicable to several ME strategies. The technique was tested in the VVC reference software implementation and showed complexity reductions of over 80% at the cost of an average 0.74% increase in BD-Rate with respect to the original TZ Search algorithm in the LDP configuration.
This paper focuses on the disparity-compensated stereoscopic image coding. This coding scheme is the most implemented technique taking advantage of the typical stereoscopic image redundancy. Namely it first predicts o...
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ISBN:
(纸本)9788362065394
This paper focuses on the disparity-compensated stereoscopic image coding. This coding scheme is the most implemented technique taking advantage of the typical stereoscopic image redundancy. Namely it first predicts one view using the other view and a disparity map. A compensated view is then computed by coding the remaining difference between the view and its prediction. This paper concerns the computation of the disparity map combining two existing techniques. The first one, more efficient at low bitrate, is an iterative search reducing the bit cost of losslessly storing the disparity map at the expense of a small increase in distortion. The second one, more efficient at high bitrate, selects disparities minimizing the distortions of the compensated view, assuming that JPEG is used in the compensation. This combination appears to be fruitful, achieving increased performance at low- and mid-range bitrate, when tested on a few stereoscopic images and compared to these two techniques.
The smart city concept has attracted high research attention in recent years within diverse application domains, such as crime suspect identification, border security, transportation, aerospace, and so on. Specific fo...
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The smart city concept has attracted high research attention in recent years within diverse application domains, such as crime suspect identification, border security, transportation, aerospace, and so on. Specific focus has been on increased automation using data driven approaches, while leveraging remote sensing and real-time streaming of heterogenous data from various resources, including unmanned aerial vehicles, surveillance cameras, and low-earth-orbit satellites. One of the core challenges in exploitation of such high temporal data streams, specifically videos, is the trade-off between the quality of video streaming and limited transmission bandwidth. An optimal compromise is needed between video quality and subsequently, recognition and understanding and efficient processing of large amounts of video data. This research proposes a novel unified approach to lossy and lossless video frame compression, which is beneficial for the autonomous processing and enhanced representation of high-resolution video data in various domains. The proposed fast blockmatching motion estimation technique, namely mean predictive blockmatching, is based on the principle that general motion in any video frame is usually coherent. This coherent nature of the video frames dictates a high probability of a macroblock having the same direction of motion as the macroblocks surrounding it. The technique employs the partial distortion elimination algorithm to condense the exploration time, where partial summation of the matching distortion between the current macroblock and its contender ones will be used, when the matching distortion surpasses the current lowest error. Experimental results demonstrate the superiority of the proposed approach over state-of-the-art techniques, including the four step search, three step search, diamond search, and new three step search.
Background Augmented reality (AR) is still a primarily theoretical concept in areas such as bowel, liver, gallbladder, and jaw surgeries because of the limitation of visualization accuracy of hidden organs and interna...
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Background Augmented reality (AR) is still a primarily theoretical concept in areas such as bowel, liver, gallbladder, and jaw surgeries because of the limitation of visualization accuracy of hidden organs and internal structures. This paper aims to improve the cutting accuracy, visualizing accuracy, and processing time of the augmented video. Methodology The proposed system consists of an enhanced block-matching algorithm (BMA) with ghosting map technique. Results Results proved that proposed system reduced the visualization error, which ranges from 1.48 to 1.83 mm against the existing system visualization error 1.67 to 2.0. Similarly, the processing time also improved 59 to 72 ms/frame over the 50 to 58 ms/frame. Conclusion This study showed the improvement and solved the problem soft tissue reconstruction and visualization on the AR video that used in bowel and gallbladder surgeries.
High abstraction level models can be used within the system-level simulation to allow rapid evaluations of architectural aspects in early Design Space Exploration (DSE) and direct the development decisions. Further, e...
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ISBN:
(纸本)9781728102405
High abstraction level models can be used within the system-level simulation to allow rapid evaluations of architectural aspects in early Design Space Exploration (DSE) and direct the development decisions. Further, early DSE is of paramount importance in the specification of future Embedded Systems (ES) and its evaluation for applications with high computing demands and energy restrictions. This paper presents the exploration of Heterogeneous Task-Level Parallelism (HTLP) in a block-matching algorithm (BMA) video coding application. HTLP means the creation and execution of simultaneous threads of kernels defined for different types of Processing Elements (PE) - e.g., CPU and GPU - but all for an equal purpose. We employ a BMA implementation as a case study, and its characteristics are used to explore the HTLP - in particular, its kernels for data preparation, SAD (sum of absolute differences) criteria calculation, and SAD values grouping. For the exploration, a system-level simulation framework (SAVE-htlp) is augmented, being able to support the HTLP. In the performed experiments, SAVE-htlp simulates workload and architecture models and explores 22 settings varying the PE type employed during the tasks' execution and the number of concurrent threads for each kernel. Execution time, performance, energy, and power results show HTLP settings overcoming CPU-only ones as well as those with solely GPUs to process its tasks.
Statistical parametric mapping (SPM) provides useful voxel-by-voxel analyses of brain images from F-18-fluorodesoxyglucose positron emission tomography (FDG-PET) after an initial step of spatial normalization through ...
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Statistical parametric mapping (SPM) provides useful voxel-by-voxel analyses of brain images from F-18-fluorodesoxyglucose positron emission tomography (FDG-PET) after an initial step of spatial normalization through an anatomical template model. In the setting of the preoperative workup of patients with temporal epilepsy, this study aimed at assessing a block-matching (BM) normalization method, where most transformations are computed through small blocks, a principle that minimizes artefacts and overcomes additional image-filtering. Brain FDG-PET images from 31 patients with well-characterised temporal lobe epilepsy and among whom 22 had common mesial temporal lobe epilepsy were retrospectively analysed using both BM and conventional SPM normalization methods and with PET images from age-adjusted controls. Different threshold p values corrected for cluster volume were considered (0.01, 0.005, and 0.001). The use of BM provided equivalent values to those of SPM with regard to the overall volumes of temporal and extra-temporal hypometabolism, as well as similar sensitivity for detecting the involved temporal lobe, reaching 87 and 94 % for SPM and BM, respectively, at a threshold p value of 0.01. However, the ability to more accurately localize brain lesions within the mesial portion of the temporal lobe was a little higher with BM than with SPM with respective sensitivities reaching 78 % for BM and 45 % for SPM (p < 0.05). BM normalization compares well with conventional SPM for the voxel-based quantitative analysis of the FDG-PET images from temporal epilepsy patients. Further studies in different population are needed to determine whether BM is truly an accurate alternative to SPM in this setting.
Motion estimation is extensively used in multimedia tasks, video coding standards and home consumer devices, appearing in many FFT-based motion algorithms. On other hand, the intellectual properties of embedded microp...
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Motion estimation is extensively used in multimedia tasks, video coding standards and home consumer devices, appearing in many FFT-based motion algorithms. On other hand, the intellectual properties of embedded microprocessor systems are typically delivered on HDL and C source code levels. Obfuscating the code is most often the only way to protect and avoid reverse engineering. This paper presents an evaluation of operations widely used in motion estimation for an embedded microprocessor for protection purposes. A set of open source obfuscation tools has been developed that allows the use of very long and hard-to-read identifiers. The implementation of comment methods also allows for the addition of copyright and limited warranty information. The obfuscated code with identifiers of up to 2,048 characters in length is tested for Altera's and Xilinx's field programmable gate arrays for a typical HDL example. Compiler penalties as well as FFT runtime results are reported.
The impact of age is crucial and must be taken into account when applying a voxel-based quantitative analysis on brain images from [F-18]-fluorodeoxyglucose Positron Emission Tomography (FDG-PET). This study aimed to ...
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The impact of age is crucial and must be taken into account when applying a voxel-based quantitative analysis on brain images from [F-18]-fluorodeoxyglucose Positron Emission Tomography (FDG-PET). This study aimed to determine whether age-related changes in brain FDG-PET images are more accurately assessed when the conventional statistical parametric mapping (SPM) normalization method is used with an adaptive template, obtained from analysed PET images using a block-matching (BM) algorithm to fit with the characteristics of these images. Age-related changes in FDG-PET images were computed with linear models in 84 neurologically healthy subjects (35 women, 19 to 82-year-old), and compared between results provided by the SPM normalization algorithm applied on its dedicated conventional template or on the adaptive BM template. A threshold P value of 0.05 was used together with a family-wise error correction. The age-related changes in FDG-PET images were much more apparent when computed with the adaptive template than with the conventional template as evidenced by: (1) stronger correlation coefficients with age for the overall frontal and temporal uptake values (respective R (2) values of 0.20 and 0.07) and (2) larger extents of involved areas (13 and 5 % of whole brain template volume, respectively), leading to reveal several age-dependent areas (especially in dorsolateral prefrontal, inferior temporal/fusiform and primary somatosensory cortices). Age-related changes in brain FDG uptake may be more accurately determined when applying the SPM method of voxel-based quantitative analysis on a template that best fits the characteristics of the analysed TEP images.
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