Efficient Video Coding based on Audio-Visual Focus of Attention

This paper proposes an efficient video coding method using audio-visual focus of attention, which is based on the observation that sound-emitting regions in an audio-visual sequence draw viewers' attention. First, an audio-visual source localization algorithm is presented, where the sound source is identified by using the correlation between the sound signal and the visual motion information. The localization result is then used to encode different regions in the scene with different quality in such a way that regions close to the source are encoded with higher quality than those far from the source. This is implemented in the framework of H.264/AVC by assigning different quantization parameters for different regions. Through experiments with both standard and high definition sequences, it is demonstrated that the proposed method can yield considerable coding gains over the constant quantization mode of H.264/AVC without noticeable degradation of perceived quality

Subjective quality evaluation of foveated video coding using audio-visual focus of attention

This paper presents a foveated coding method using audio-visual focus of attention and its evaluation through extensive subjective experiments on both standard definition and high definition sequences. Regarding a sound-emitting region as the location drawing the human attention, the method applies varying quality levels in an image frame according to the distance of a pixel to the identified sound source. Two experiments are presented to prove the efficiency of the method. Experiment 1 examines the validity and effectiveness of the method in comparison to the constant quality coding for high quality conditions. In Experiment 2, the method is compared to the fixed bit rate coding for low quality conditions where coding artifacts are noticeable. The results demonstrate that the foveated coding method provides considerable coding gain without significant quality degradation, but uneven distributions of the coding artifacts (blockiness) by the method are often less preferred than the uniform distribution of the artifacts. Additional interesting findings are also discussed, such as content dependence of the performance of the method, the memory effect in multiple viewings, and the difference in the quality perception for frame size variations

Subjective quality evaluation via paired comparison: application to scalable video coding

Scalable video coding is a powerful solution for content delivery in many interactive multimedia services due to its adaptability to varying terminal and network constraints. In order to successfully exploit such adaptability, it is necessary to understand users' preference among various scalability options and consequently develop an optimal bit rate adaptation strategy. In this paper, we present a study of subjective quality assessment of scalable video coding, which investigates the influence of the combination of scalability options on perceived quality with the goal of providing guidelines for an adaptive strategy that selects the optimal combination for a given bandwidth constraint. In particular, the study is based on paired comparison of stimuli that is suitable for our goal due to its simplicity and easiness. We propose a new method, called Paired Evaluation via Analysis of Reliability (PEAR), which analyzes paired comparison results and produces not only quality scores but also intuitive measures of confidence of the scores for significance analysis. Results and analysis of extensive subjective tests for two different scalable video codecs and high definition contents are described, from which general consistent conclusions are drawn. The video and subjective data used in the paper are publicly available to the research community. (http://mmspg.epfl.ch/svd

Evaluation of the functionality of bread loaves prepared with quinoa flakes through biological tests

O objetivo deste estudo foi avaliar os flocos de quinoa e os pães elaborados com o pseudocereal, tanto em relação a aspectos nutricionais por meio da análise da composição centesimal, do teor de tocoferóis, composição em ácidos graxos, quanto aos possíveis efeitos benéficos, através de experimento com ratos Wistar, consumindo ração comercial, suplementados ou não com flocos de quinoa e colesterol. Foram determinados: ganho de peso, consumo de alimento, peso e gordura do fígado e perfil lipídico do sangue e do fígado. Pelos resultados, verificou-se que o processamento afetou as características nutricionais dos pães, pois houve aumento significativo no teor de fibras totais, porém redução nas fibras solúveis. O aumento de fibras não influenciou no consumo alimentar nem no ganho de peso. Em relação à gordura do fígado dos ratos, o grupo que consumiu pão sem quinoa com colesterol apresentou maior teor de lipídios. A adição de quinoa incrementou significativamente o teor de alguns tipos de tocoferóis, principalmente no grupo de animais que consumiu o pão com 20% de quinoa, melhorando o perfil lipídico, tanto do sangue quanto do fígado, principalmente devido à redução do LDLoxidado.The aim of this study was to evaluate quinoa flakes and bread prepared with the pseudocereal with regard to nutritional aspects by determining chemical composition, content of tocopherols and fatty acid composition as well as to possible beneficial effects in Wistar rats given commercial feed supplemented or not with quinoa flakes and cholesterol. The following parameters were determined: weight gain, food intake, liver weight, fat in liver and lipid profile in blood and liver. The results showed that processing affected the nutritional characteristics of bread because there was a significant increase in dietary fiber content but reduction in soluble fiber. Increased fiber did not influence food intake or weight gain. Regarding fat in liver of rats, the group that consumed bread without quinoa but with cholesterol showed higher lipid content. The addition of quinoa increased significantly the level of all types of tocopherols, especially in the group of animals that consumed 20% quinoa bread, improving the lipid profile both in blood and liver, largely due to a reduction in oxidized LDL

Atherosclerosis, C-reactive protein, and risk for open-angle glaucoma: The Rotterdam Study

PURPOSE. To test the hypotheses that atherosclerosis and elevated serum C-reactive protein (CRP) levels are risk factors for open-angle glaucoma (OAG). METHODS. In a prospective, population-based cohort study, all participants 55 years and older and at risk for incident OAG underwent, at baseline (1990-1993) and at follow-up (1997-1999), the same ophthalmic examination, including visual field testing and optic disc photography. Baseline atherosclerosis was assessed by means of echography of the carotid arteries, abdominal x-ray examination, and ankle-arm index; baseline serum CRP levels were used in the analyses. The diagnosis of OAG was based on an algorithm using optic disc measures and visual field loss. Odds ratios of OAG were computed with logistic regression analyses. Risk factors were categorized in tenues and according to standard deviation. RESULTS. After a mean follow-up of 6.5 years, incident OAG was diagnosed in 87 of 3842 (2.3%) participants at risk for OAG. Carotid artery plaques, carotid intima-media thickness, aortic calcifications, ankle-arm index, and CRP levels were not significant risk factors for OAG. The odds ratio, given for the highest and lowest tertiles, for carotid plaques was 1.43 (95% confidence interval [CI], 0.68-2.99), for carotid intima-media thickness 0.86 (95% CI, 0.47-1.57), for aortic calcifications 1.02 (95% CI, 0.60-1.75), for ankle-arm index 0.69 (95% CI, 0.38-1.25), and for CRP 1.19 (95% CI, 0.68-2.07). CONCLUSIONS. In this prospective, population-based study, neither atherosclerosis nor serum CRP level was an important risk factor for OAG.

Protective effect of guabiju (Myrcianthes pungens (O. Berg) D. Legrand) and red guava (Psidium cattleyanum Sabine) against cisplatin-induced hypercholesterolemia in rats

The present study was the first to examine the protective effect and antioxidant potential of two fruits native to the south of Brazil, namely guabiju (Myrcianthes pungens (O. Berg) D. Legrand) and red guava (Psidium cattleyanum Sabine), with respect to reducing the effects of cisplatin-induced hypercholesterolemia in male Wistar rats. The cisplatin-treated animals showed high glucose, LDL cholesterol, oxidized LDL cholesterol and total cholesterol levels. These native fruits reversed the increase in these parameters. The fat levels in the liver improved with supplementation with the fruits, and there were no differences in the thiobarbituric acid reactive substances (TBARS), creatinine, urea or HDL cholesterol levels, nor in the weight of the organs analyzed, indicating that the dose used did not affect these markers.O presente estudo foi o primeiro realizado para avaliar o efeito protetor e o potencial antioxidante de duas frutas nativas do sul do Brasil, conhecidas como Guabiju (Myrcianthes pungens (O. Berg) D. Legrand) e araçá vermelho (Psidium cattleyanum Sabine), em relação a reduzir os efeitos da hipercolesterolemia induzida pela cisplatina em ratos Wistar machos. Os animais tratados com a cisplatina apresentaram elevada taxa de glicose, altos níveis de colesterol LDL, colesterol LDL oxidado e colesterol total. Os frutos nativos atuaram protegendo os animais pela redução destes parâmetros. Os níveis de gordura no fígado melhoraram com a suplementação pelos frutos e não houve diferenças nas substâncias reativas ao ácido tiobarbitúrico (TBARS) e níveis de creatina, uréia e colesterol HDL e, também, no peso dos órgãos analisados, indicando que a dose utilizada não foi capaz de afetar tais marcadores

Associations between polygenic risk scores for four psychiatric illnesses and brain structure using multivariate pattern recognition

Psychiatric illnesses are complex and polygenic. They are associated with widespread alterations in the brain, which are partly influenced by genetic factors. There have been some attempts to relate polygenic risk scores (PRS) - a measure of the overall genetic risk an individual carries for a disorder - to brain structure using univariate methods. However, PRS are likely associated with distributed and covarying effects across the brain. We therefore used multivariate machine learning in this proof-of-principle study to investigate associations between brain structure and PRS for four psychiatric disorders; attention deficit-hyperactivity disorder (ADHD), autism, bipolar disorder and schizophrenia. The sample included 213 individuals comprising patients with depression (69), bipolar disorder (33), and healthy controls (111). The five psychiatric PRSs were calculated based on summary data from the Psychiatric Genomics Consortium. T1-weighted magnetic resonance images were obtained and voxel-based morphometry was implemented in SPM12. Multivariate relevance vector regression was implemented in the Pattern Recognition for Neuroimaging Toolbox (PRoNTo). Across the whole sample, a multivariate pattern of grey matter significantly predicted the PRS for autism (r = 0.20, pFDR = 0.03; MSE = 4.20 × 10-5, pFDR = 0.02). For the schizophrenia PRS, the MSE was significant (MSE = 1.30 × 10-5, pFDR = 0.02) although the correlation was not (r = 0.15, pFDR = 0.06). These results lend support to the hypothesis that polygenic liability for autism and schizophrenia is associated with widespread changes in grey matter concentrations. These associations were seen in individuals not affected by these disorders, indicating that this is not driven by the expression of the disease, but by the genetic risk captured by the PRSs

Performance analysis of VP8 image and video compression based on subjective evaluations

Today, several alternatives for compression of digital pictures and video sequences exist to choose from. Beside internationally recognized standard solutions, open access options like the VP8 image and video compression have recently appeared and are gaining popularity. In this paper, we present the methodology and the results of the rate-distortion performance analysis of VP8. The analysis is based on the results of subjective quality assessment experiments, which have been carried out to compare the two algorithms to a set of state of the art image and video compression standards