English

The existence of temporal effects and temporal distortions in a video differentiate the way it is assessed from an image. Temporal effects and distortions can enhance or depress the visibility of spatial effects in a video. Thus, the temporal part of videos plays a significant role in determining the video quality. In this study, a spatiotemporal video quality assessment (VQA) method is proposed due to the importance of temporal effects and distortions in assessing video quality. Instead of measuring the frame quality on a frame basis, the quality of several averaged frames is measured. The proposed spatiotemporal VQA method is significantly improved compared with image quality assessment (IQA) methods applied on a frame basis. When combined with IQA methods, the proposed spatiotemporal VQA method has comparable performance with state-of-the-art VQA methods. The computational complexity of the proposed temporal method is also lower when compared with current VQA methods.

The necessity of multi-spectral improved vision systems usage is shown. Image contrast enhancing algorithms are considered. The modification proposed allows to reduce the influence of artifacts in image areas with sharp brightness variety. Full-reference quality assessment of contrast enhancement algorithms application results is realized. Multispectral image dataset is created. The values of objective and subjective multispectral image fusion quality assessments and one subjective assessment are obtained. Correlation coefficients between subjective and objective assessments are calculated. It is shown that the Pearson product-moment correlation coefficient between objective and specified subjective image fusion quality assessments are not less than 0.54.

Liquid crystal displays (LCDs) have appeared in applications ranging from medical equipment to automobiles, gas pumps, laptops, and handheld portable computers. These display components present a cascaded energy attenuator to the battery of the handheld device which is responsible for about half of the energy drain at maximum display intensity. As such, the display components become the main focus of every effort for maximization of embedded system's battery lifetime. This paper proposes an approach for pixel transformation of the displayed image to increase the potential energy saving of the backlight scaling method. The proposed approach takes advantage of human visual system (HVS) characteristics and tries to minimize distortion between the perceived brightness values of the individual pixels in the original image and those of the backlight-scaled image. This is in contrast to previous backlight scaling approaches which simply match the luminance values of the individual pixels in the original and backlight-scaled images. Furthermore, this paper proposes a temporally-aware backlight scaling technique for video streams. The goal is to maximize energy saving in the display system by means of dynamic backlight dimming subject to a video distortion tolerance. The video distortion comprises of: 1) an intra-frame (spatial) distortion component due to frame-sensitive backlight scaling and transmittance function tuning and 2) an inter-frame (temporal) distortion component due to large-step backlight dimming across frames modulated by the psychophysical characteristics of the human visual system. The proposed backlight scaling technique is capable of efficiently computing the flickering effect online and subsequently using a measure of the temporal distortion to appropriately adjust the slack on the intra-frame spatial distortion, thereby, achieving a good balance between the two sources of distortion while maximizing the backlight dimming-driven energy saving in the display system and meeting an overall video quality figure of merit. The proposed dynamic backlight scaling approach is amenable to highly efficient hardware realization and has been implemented on the Apollo Testbed II. Actual current measurements demonstrate the effectiveness of proposed technique compared to the previous backlight dimming techniques, which have ignored the temporal distortion effect

Узагальнено результати опрацювань наявних теоретико-аналітичних матеріалів щодо вимірювання якості життя, виявлено їх спрямованість переважно на оцінювання якості життя на макрорівні для міжнародних порівнянь. Обґрунтовано й запропоновано методичні прийоми з оцінювання екологічної безпеки як складової якості життя на рівні адміністративних субрегіонів сусідніх країн: суб’єктивного оцінювання на основі соціологічного дослідження із застосуванням анкетування та об’єктивного оцінювання з вибором репрезентативних, порівняльних, достовірних оціночних показників, обґрунтуванням їх нормативних значень і проведенням розрахунків індексів екологічної безпеки. Наведено результати апробації запропонованих методичних прийомів з висвітленням суб’єктивних і отриманих на основі кількісних показників, адаптованих до системи офіційної статистики України та Польщі об’єктивних оцінок екологічної складової якості життя в досліджуваних транскордонних субрегіонах – Жовківському, Сокальському, Яворівському районах Львівської області України та Любачівському, Перемишльському, Ярославському повітах Підкарпатського воєводства Польщі. Виявлено суттєві диспропорції не на користь вітчизняних субрегіонів у рівнях екологічної безпеки за результатами об’єктивної оцінки, що певною мірою згладжується при суб'єктивному оцінюванні через його залежність від специфіки ціннісних настанов і орієнтирів та екологічної обізнаності респондентів. Зроблено висновки щодо взаємодоповнюваності результатів суб’єктивного й об’єктивного оцінювання екологічної безпеки, високої оцінки респондентами важливості екологічної безпеки як складової якості життя, впливу асиметрії екологічної безпеки на результати її суб’єктивної оцінки, зокрема, стосовно пріоритетності захисту і збереження тих чи інших компонентів природного довкілля, націлених на вирішення цих завдань.

Reliable estimation of optical flow vectors facilitates the evaluation of the motion of a camera relative to the environment. Furthermore, optical flow vectors comprise information about the 3D structure of the recorded scene. In this contribution we present an approach for the detection of stationary obstacles and moving objects in front of a vehicle. The detection of obstacles and other objects is based on the evaluation of optical flow. The optical flow vectors are calculated with a local analytical approach. The necessary first and second order spatio-temporal derivatives are computed in real-time with our second-generation custom designed image sequence analysis system MiniVISTA. At all image locations it is tested whether the structure of the gray value distribution is sufficient for a local optical flow vector calculation or not. Only those sets of spatio-temporal derivatives which passed this structure test are transmitted to subsequent processes being executed on a transputer network. Experimental results obtained from image sequences recorded on our experimental vehicles MB 609D and BMW 735 iL are presented.

Motion silencing of flicker distortions on naturalistic videos

We aimed to assess the cosmetic outcome of patients who underwent enucleation for uveal melanoma. The subjective assessment was based on a questionnaire, including four questions on postoperative cosmetic outcome. As part of the objective assessment, the following features were evaluated using a four-point scale: the symmetry of the upper eyelid sulcus, color matching between the prosthetic and healthy eye, prosthetic eye motility, and eyelid position. We enrolled 90 patients after enucleation (58 with and 32 without an orbital implant). The overall subjective assessment scores were 3.5/4 and 3.3/4 points in patients with and without an implant, respectively. The overall objective assessment scores were 3.3/4 and 2.3/4 in patients with and without an implant, respectively (p < 0.001). The cosmetic outcome was rated significantly higher by patients than by investigators (p < 0.05). There was no significant association between the overall subjective and objective assessment of the cosmetic outcome in any of the groups. Cosmetic outcome after enucleation for uveal melanoma was highly rated by patients. It was rated higher by patients than by investigators. The presence of an orbital implant was associated with higher objective assessment scores in terms of the symmetry of the upper lid sulcus, prosthetic eye motility, and eyelid position.

This study aims to evaluate the informational quality of oral cancer-related videos on YouTube and Bilibili. A total of 300 oral videos that met the inclusion and exclusion criteria were selected for analysis. The selection comprised 150 videos from 111 uploaders on YouTube and 150 videos from 134 uploaders on Bilibili. YouTube videos received a greater number of views and likes, while there was no significant difference in average likes per 30 days or comments between the two platforms. The majority of YouTube uploaders were hospitals/non-profit organizations (66.7%) and for-profit companies (17.1%), while Bilibili uploaders were mainly self-media (55.2%) and doctors (29.1%). YouTube videos covered a broader range of topics compared to Bilibili videos. Though solo narration was the most prevalent video style across both platforms, YouTube exhibited a higher preference for TV shows/documentaries (31.3%). Video quality was assessed using the four tools: Though mDISCERN (modified DISCERN) and PEMAT-Actionability (Patient Education Materials Assessment Tool) were similar across platforms, YouTube videos scored higher on PEMAT-Understandability, VIQI (Video Information and Quality Index), and GQS (Global Quality Score) in comparison to Bilibili videos. Videos produced by health professionals were considered more reliable. Spearman correlation analysis revealed no strong relationships between video quality and audience interaction. In conclusion, YouTube videos exhibited higher audience engagement and video quality, yet improvements are needed on both platforms. In order to promote high-quality health information, it is essential to encourage the development of more professional content creators and to optimize platform algorithms.

Placebo response complicates the interpretation of treatment response in both clinical practice and clinical trials in youth with attention-deficit/hyperactivity disorder (ADHD). In a pilot study comparing subjective ADHD symptom rating scales with scores obtained using the Quotient™ ADHD System (an objective computerized technology for assessment of hyper-activity, inattention, and impulsivity in ADHD), it was found that agreement between these 2 measures was not as strong as anticipated. This observation prompted us to evaluate placebo responses associated with subjective and objective assessments. Eligible study participants aged 6 to 14 years with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition ADHD diagnosis based on clinician interviews were randomized to 1 of 2 treatment sequence groups (placebo, low dose, and medium dose; or low dose, medium dose, and placebo) using either atomoxetine HCl or osmotic controlled-release (OROS) methylphenidate HCl as the active treatment in a 3-week, triple-blind (subject, parent, rater) trial. Subjects were exposed to placebo and different medication doses to evaluate the comparative sensitivity of objective and subjective measures in assessing changes in clinical condition. Placebo response was defined using 3 thresholds: any improvement, > 25% improvement, or > 40% improvement from baseline on Quotient™ Global Scaled Score (QGSS) or the ADHD Rating Scale (ADHD-RS) Total score from baseline to the visit when placebo was administered. Lin's concordance correlation coefficient was used to measure agreement between baseline and placebo scores for the objective and subjective assessments. Of 30 subjects with placebo and baseline scores, 80%, 47%, and 27% met the 3 response thresholds (ie, any, > 25%, or > 40% improvement, respectively) on the ADHD-RS Total score compared with 27%, 7%, and 0% on the QGSS. Lin's concordance correlation coefficient was 0.81 and 0.39 for the QGSS and the ADHD-RS Total score, respectively. Although larger trials are warranted, we tentatively conclude that using objective measures and higher response thresholds may enhance assay sensitivity in clinical trials and hence limit necessary patient enrollments to rule out type II statistical error.

Background: Parental reports of their children’s health status is integral to pediatric medical and dental care. Therefore, understanding the accuracy of such reports is vital. Our objectives were to (1) assess the correlation between maternal reports of their children’s indicators of caries experience (subjective assessment) and actual caries status determined by oral examination (objective assessment), and (2) identify potential modifiers of this correlation. Methods: Longitudinal data from the Avon longitudinal study of parents and children (n = 1429) was used to assess the correlation between maternal reports of the number of missing and filled teeth of children aged 38 months, 54 months, and 5.5 years and clinical oral examinations of decayed, missing and filled teeth conducted when the same children were 31, 43 months, and five years of age. Homogeneity chi-square tests assessed differences in correlations according to sociodemographic factors. Results: Overall, we found a statistically significant correlation that was weak to moderate in magnitude. Maternal reports of missing teeth at 38 months was significantly correlated with decayed teeth, 0.27 (p < 0.001); missing teeth, 0.23 (p < 0.001), and the decayed, missing and filled (dmft) index, 0.35 (p < 0.001) based on oral examination at 31 months. A maternal report of filled teeth at 54 months was significantly correlated with decayed teeth, 0.30 (p < 0.001); filled teeth 0.30 (p < 0.001), and dmft 0.40 (p < 0.001) at 43 months. Mothers tended to underestimate the extent of missing and filled teeth in their children irrespective of the child’s age, but the extent of underestimation was greater among younger children. Maternal age, education level, and whether the child had ever visited a dentist were significant modifiers of subjective and objective caries assessments. Conclusions: From a clinical and dental public health perspective, our findings of a weak to moderate correlation of maternal assessments of their children’s caries experience may be concerning when reporting the burden of dental diseases in large population studies or for surveillance purposes that rely on self-reported measures and must therefore be utilized with caution because of the potential to result in underestimated disease burden.

This paper proposes a new algorithm for abnormal behavior detection in surveillance video. Firstly, the motion information image of each frame is constructed by calculating the optical flow size and the angle difference between the optical flow vectors between consecutive frames, and then the obtained motion image information is input into the convolutional neural network (CNN) for training, and used for video abnormal behavior detection. In the algorithm, the motion information image generated based on optical flow information can provide the motion information features in the video image more accurately, which makes it easier to distinguish the normal behavior and abnormal behavior of the video. The experiment of this algorithm is carried out on the commonly used data set PETS 2009. Experimental results show that the proposed method and other algorithms have a significant improvement in the accuracy of abnormal behavior detection.

A gesture motion detection algorithm based on optical flow method is elaborated in this paper as significant way of human-computer interaction. The skin color segmentation algorithm based on ellipse skin color model in YCbCr color space and Pyramid Lucas-Kanade optical flow method constitute the basic modules of gesture motion detection. The skin color areas are selected in sequence by skin color segmentation algorithm which produce the optical flow vectors within the Pyramid Lucas-Kanade optical flow module. Optical flow vectors of the adjacent two frames after isolation are used as parameters for judging direction. When two results after judgment are consistent, the direction of gesture movement is determined. The algorithm proposed in this paper, testified from the experiments, is of high accuracy and less time-consuming which can be applied in real-time broadly.

High definition television (HDTV) video delivery services over IP networks have recently started. To make the delivered high-quality HDTV video comfortable to view, we need to design appropriate delivery systems and then monitor the quality of experience. Currently, subjective assessment is the main method used to quantify video quality. However, it is unsuitable for real time monitoring of video quality. Therefore, we need an objective video quality assessment method that can effectively estimate subjective video quality from the video characteristics. We propose a full-reference-type objective video quality measurement method that is applicable to the evaluation of coding distortions in HDTV. We analyzed the results from applying the conventional method (J.247 Annex A) to HDTV video and improved the conventional method on the basis of those results. We applied fuzzy measure to the conventional method so as to consider the interaction effects of each parameter because the conventional method tends to obtain different characteristics between high quality and low quality regions of video content.

Reliably predicting how humans assess video quality aspects remains an academic challenge, partly due to our limited understanding of human visual system and of how it affects the perception of spatial and temporal distortions. In current video chains, the perceived quality varies over time, depending on the compression level and video content. However, the impact of both factors on the extent of such variation is unknown, while this knowledge would be highly beneficial for video quality modeling. In this paper, a perception experiment is conducted with human observers rating the quality and meanwhile the extent of quality variation over time (QVT) for a set of video sequences. Preliminary results show that QVT tends to be less observed in the low and high quality regions; and that QVT seems to be sensitive to video content independent of compression level.

Chapter 4 - Subjective and objective quality assessment for omnidirectional video