557 research outputs found
Frequency-Domain Intra Prediction Analysis and Processing for High-Quality Video Coding
keywords: Decoding;Discrete cosine transforms;Encoding;Frequency-domain analysis;Image coding;Video codin
Studying Rate Control Methods for UHDTV Delivery Using HEVC
Since the early video coding standardisation efforts, rate control has been considered essential for almost any application, and has therefore been extensively studied. With the advent of improved video coding standards, such as the current stateof-the-art High Efficiency Video Coding (HEVC) standard, and the introduction of advanced flexible coding tools, previous Rate-Distortion (RD) models used for rate control have become obsolete. To address this issue, some rate control methods have been recently proposed specifically for HEVC which introduce many useful features, such as a robust correspondence between the rate and Lagrange multiplier . However, when applying these rate control methods on sequences in the new Ultra High Definition Television (UHDTV) format, degraded coding performance was observed. In this paper, an analysis of the state-of-the-art HEVC rate control method was performed and two directions for its improvement were evaluated. These improvements target frame-level bit-allocation and model parameter initialisation. When compared to the rate control method implemented in the HEVC reference software, these improvements result in reduced BDrate losses of 3:1% and 2:1%, versus the 8:8% provided by the reference algorithm. Moreover, the proposed improvements improve the accuracy in hitting the target bit-rate./p
Description of Testing in Wavelet Video Coding
The provided testing scenario is intended to be used for evaluation of the coding performance of the JSVM coding scheme provided by JVT, with respect to the Exploration Wavelet Video Coding platform. The reference conditions have been derived from the JSVM testing conditions document JVT-P205 produced at the 16th JVT meeting in Poznan. Further details on JSVM configuration can be found in such document. The rate points to be used in all tests are derived from the combined scalability test sets. The applicable set of rate points is similar to the rate points originally applied in the Munich and Palma testing conditions. The target rates are arranged in a systematic manner.
For each spatio-temporal resolution, the rate triples from the lowest rate point to the highest rate point. The settings are chosen such that an AVC compatible base layer can be provided for the base layer of combined and spatial scalability and for the QCIF sequences in the SNR scalability scenario. The encoder will generate embedded bit-streams. To extract the various bit-rates, frame-rates and resolutions specified in the tables below from the embedded bit-stream, an extractor shall be used. No transcoding is allowed for performing the decoding at the various bit-rates, frame-rates and resolutions. In the combined scalability settings, the testing addresses a broad range scalability and is
motivated by the requirements of applications such as surveillance, broadcast and storage systems. This scenario is represented by the test sequences CITY, CREW, HARBOUR and SOCCER. Visual tests shall take place for the rates shown in green in the tables below for each spatial resolution, and for the Palma test at the rate points tested at Palma. PSNR curves will have to be provided for all other rate points
Quality prescribing in general practice
To implement continuous improvement of prescribing in general practice with a model closely linking the work of general practitioner and a clinical pharmacist aiming to improve the safety and efficiency of treatment with medicine. Emphasise is on polypharmacy (multiple medications) which is increasing across countries and although appropriate especially in patients with multiple comorbidities it can cause serious problems to patients and is a major challenge for the health care systems. Problems include adverse drug reactions and harmful drug interactions with reduced quality of life, increased overall morbidity, mortality and increased costs to health care systems
Dynamic layout of visual summaries for scalable video
The paper brings a novel method for generating visual summaries of scalable videos. The generated summaries can dynamically adapt to requirements defined by display size, userpsilas needs or channel limitations. It utilises compressed domain features coupled with efficient contour evolution algorithm in order to generate a scale space of temporal video descriptors. The layout of the visual summary is created using an efficient graph clustering technique and a fast discrete optimisation algorithm, enabling dynamic video summarisation in real-time. The experimental results show good scalability of the dynamic layout and highly efficient generation of visual summaries
Estimation of Rate Control Parameters for Video Coding Using CNN
Rate-control is essential to ensure efficient video delivery. Typical rate-control algorithms rely on bit allocation strategies, to appropriately distribute bits among frames. As reference frames are essential for exploiting temporal redundancies, intra frames are usually assigned a larger portion of the available bits. In this paper, an accurate method to estimate number of bits and quality of intra frames is proposed, which can be used for bit allocation in a rate-control scheme. The algorithm is based on deep learning, where networks are trained using the original frames as inputs, while distortions and sizes of compressed frames after encoding are used as ground truths. Two approaches are proposed where either local or global distortions are predicted
Assessment of deep cryogenic heat-treatment impact on the microstructure and surface chemistry of austenitic stainless steel
This systematic study deals with the influence of deep cryogenic treatment (DCT) on microstructure and surface properties of austenitic stainless steel AISI 304 L on different length scales and in the surface region. The study incorporates different analysis techniques, such as light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ions mass spectrometry (ToF-SIMS). DCT modifies the microstructure of treated samples through promoted precipitation of Cr7C3 carbides, induced twinning and α-martensite formation. Additionally, XPS/AR-XPS and ToF-SIMS results also provide evidence of modified oxidation dynamics of DCT samples compared to conventionally heat-treated samples with increase of the Fe-oxide fraction and lower Cr-oxide fraction in the surface oxide layer. An evaluation of oxidation states and ions distribution within the surface layer of deep cryogenically heat-treated stainless steel AISI 304 L is conducted with XPS/ToF-SIMS. These results are correlated with the microstructural changes and nitrogen diffusivity induced by DCT, which are associated with modified oxidation behaviour of AISI 304 L. These results provide further understanding of DCT dynamic on the overall microstructure and the corresponding surface behaviour
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