Subjective Quality Assessment Research Articles

Психологические особенности женщин, больных раком молочной железы на стадии ремиссии и четвертой стадии

Breast cancer is one of the most common types of cancer worldwide. The specific situation of the disease at certain stages, for example, at the stage of remission and the fourth stage, may contribute to the manifestation of certain psychological characteristics in cancer patients, which can be considered as personal resources for the adaptation of women with breast cancer to the disease situation. It is assumed that the complex of psychological characteristics studied in the study makes it possible to fully reflect the adaptive potential of a person in overcoming a difficult life situation, including one associated with a life-threatening disease. Objective. To study the psychological characteristics of women diagnosed with breast cancer at the stage of remission and the fourth stage. Materials and methods. The study involved 140 women aged 26 to 80 years. The study included patients with stage 4 (N=42) and women with remission from 6 months (N=98). Survey methods were used as research methods: the scale of basic beliefs (adaptation by M. A. Padun, A.V. Kotelnikova); the test of life orientations (adaptation by D.A. Tsiring, K.Yu. Evnina); the test of resilience (adaptation by D. Leontiev); questionnaire of subjective control (adaptation by E.F. Bazhin, S.A. Golynkin, A.M. Etkind); questionnaire of personal helplessness (D.A. Tsiring, A.V. Stepanenko); questionnaire "Subjective age of a person" (adaptation by E.A. Sergienko); subjective assessment of quality of life (questionnaire SF-36). Methods of mathematical processing: primary descriptive statistics, comparative analysis (U-Mann-Whitney criterion). Results. Psychological features of women with breast cancer at stage 4 were found, distinguishing them from women with breast cancer at the stage of remission in terms of the picture of the world, indicators of quality of life, personal helplessness-independence, subjective control, resilience. Conclusion. The data obtained indicate the presence of a special complex of psychological characteristics that occurs at a certain stage of the disease, and reflects the adaptive potential of women with breast cancer in overcoming a difficult life situation associated with a lifethreatening disease.

Assessment of Image Quality in Chest CT With Precision Matrix and Increased Framing Rate Using Single Source CT: A Phantom Study.

The aim was to evaluate the effect of a combined precision matrix and high sampling rate on the delineation of anatomical structures and objective image quality in single source CT in a qualitative approach. An anthropomorphic thoracic phantom was used to evaluate the objective image quality parameters, including image noise, noise power spectrum, image stepness and Q for different CT scanners including high/standard matrix and framing frequency setups. Scan parameters were standardized over all scanners. Additional subjective quality assessment was also performed. A linear mixed effects model was used to determine the effect of sampling rate and image matrix on objective image quality parameters. Noise power spectrum and image noise were significantly influenced by both framing frequency and image matrix. There were significant differences between high and standard frequency/matrix acquisitions. Higher framing frequency and image matrix allows for improved image noise texture and objective image quality in CT.

RV-TMO: Large-Scale Dataset for Subjective Quality Assessment of Tone Mapped Images

Tone mapping operators (TMO) are functions that map high dynamic range (HDR) images to a standard dynamic range (SDR), while aiming to preserve the perceptual cues of a scene that govern its visual quality. Despite the increasing number of studies on quality assessment of tone mapped images, current subjective quality datasets have relatively small numbers of images and subjective opinions. Moreover, existing challenges in transferring laboratory experiments to crowdsourcing platforms put a barrier for collecting large-scale datasets through crowdsourcing. In this work, we address these challenges and propose the RealVision-TMO (RV-TMO), a large-scale tone mapped image quality dataset. RV-TMO contains 250 unique HDR images, their tone mapped versions obtained using four TMOs and pairwise comparison results from seventy unique observers for each pair. To the best of our knowledge, this is the largest dataset available in the literature for quality evaluation of TMOs by the number of tone mapped images and number of annotations. Furthermore, we provide a content selection strategy to identify interesting and challenging HDR images. We also propose a novel methodology for observer screening in pairwise experiments. Our work does not only provide annotated data to benchmark existing objective quality metrics, but also paves the path to building new metrics for tone mapping quality evaluation.

A personal acquisition time regimen of 68Ga-DOTATATE total-body PET/CT in patients with neuroendocrine tumor (NET): a feasibility study

BackgroundThe injection activity of tracer, acquisition time, patient-specific photon attenuation, and large body mass, can influence on image quality. Fixed acquisition time and body mass related injection activity in clinical practice results in a large difference in image quality. Thus, this study proposes a patient-specific acquisition time regimen of 68 Ga-DOTATATE total-body positron emission tomography-computed tomography (PET/CT) to counteract the influence of body mass (BM, kg) on image quality, and acquire an acceptable and constant image of patients with neuroendocrine tumors (NETs).MethodsThe development cohort consisting of 19 consecutive patients with full activity (88.7–204.9 MBq, 2.0 ± 0.1 MBq/kg) was to establish the acquisition time regimen. The liver SNR (signal-to-noise ratio, SNRL) was normalized (SNRnorm) by the product of injected activity (MBq) and acquisition time (min). Fitting of SNRnorm against body mass (BM, kg) in linear correlation was performed. Subjective assessment of image quality was performed using a 5-point Likert scale to determine the acceptable threshold of SNRL, and an optimized acquisition regimen based on BM was proposed, and validated its feasibility through the validation cohort of 57 consecutive NET patients with half activity (66.9 ± 11.3 MBq, 1.0 ± 0.1 MBq/kg) and a fixed acquisition time regimen.ResultsThe linear correlation (R2 = 0.63) between SNRnorm and BM (kg) was SNRnorm = -0.01*BM + 1.50. The threshold SNRL of acceptable image quality was 11.2. The patient-specific variable acquisition time regimen was determined as: t (min) = 125.4/(injective activity)*(-0.01*BM + 1.50)2. Based on that proposed regimen, the average acquisition time for acceptable image quality in the validation cohort was 2.99 ± 0.91 min, ranging from 2.18 to 6.35 min, which was reduced by 36.50% ~ 78.20% compared with the fixed acquisition time of 10 min. Subjective evaluation showed that acceptable image quality could be obtained at 3.00 min in the validation group, with an average subjective score of 3.44 ± 0.53 (kappa = 0.97, 95% CI: 0.96 ~ 0.98). Bland–Altman analysis revealed good agreement between the proposed regimen and the fixed acquisition time cohort.ConclusionA patient-specific acquisition time regimen was proposed in NET patients in development cohort and validated its feasibility in patients with NETs in validation cohort by 68 Ga-DOTATATE total-body PET/CT imaging. Based on the proposed regimen, the homogenous image quality with optimal acquisition time was available independent of body mass.

Assessment of life quality and health perception among recovered COVID-19 patients: multivariate analysis - own material and a review of previous reports on life quality assessment among convalescents.

The SARS-CoV-2 virus, causing acute respiratory disease, is responsible for the COVID-19 pandemic, which began in early 2020. In addition to symptoms typical of respiratory tract infections, the virus causes a number of non-specific, often long-lasting effects that hinder the daily functioning of individuals. The aim of the study was a subjective assessment of life quality and health perception among recovered COVID-19 patients. The study included 337 subjects who had been infected with SARS-CoV-2 confirmed by a positive RT-PCR test. The study participants were of legal age. The convalescents completed a questionnaire that contained 26 questions about gender, height, body weight, blood type, general and specific symptoms, comorbidities, hospital stay and duration of specific symptoms, the severity of which was assessed on the Visual Analogue Scale (VAS). The subjects determined whether the COVID-19 infection influenced their health perception and life quality. According to 46% of the respondents, COVID-19 had an impact on their quality of life and health. The chance for patients to notice the negative effects of COVID-19 on their current health status and life quality increased with each subsequent symptom of the disease by 49%, with each day of its occurrence by 3%, and with each VAS point of the severity of all infection symptoms by 30%. The study shows that COVID-19 disease affects life quality and overall health perception after recovery. Significant impact of COVID-19 on the quality of life should be a signal to create mental support and rehabilitation programs for convalescents to minimize discomfort and shorten the duration of absenteeism from work. Med Pr. 2022;73(6).

Image quality in abdominal CT: A comparison of two reconstruction algorithms in Filtered Back Projection (FBP)

Objectives: The aim of this study was to evaluate the effect of the choice of kernel on the image quality in abdominal CT images with focus on liver lesion visibility. Methods: In this comparative study 84 abdominal CT examinations of patients with liver lesions that included parallel series reconstructed with two different kernels (B30 and B45) were analyzed. The subjective assessment of image quality was performed using visual grading analysis based on anatomical criteria, liver lesion visibility and perceived image quality. Objective image quality was assessed by measurements of Hounsfield unit (HU) values (average and standard deviation) in abdominal organs and calculations of contrast-to-noise ratios (CNR). Results: B30 kernel performed significantly better than B45 in all criteria except for sharpness. The most considerable improvement of the image quality was in terms of subjective experienced image noise, overall diagnostic image quality and visually sharp reproduction of liver lesions. The physical measurements showed that CNR increased by up to 46% when using B30. Conclusions: Using a B30 kernel algorithm for image reconstruction reduces noise and by that improves image quality and diagnostic accuracy significantly when compared to B45.

Influence of bisoprolol and nebivolol on the regulatory-adaptive status of patients with diastolic chronic heart failure

Background. Chronic heart failure (CHF) is the most common outcome of cardiovascular disease, of hypertension disease (HD). Beta-blockers contribute to the correction of hypertension, reduce heart remodeling, slow the progression of CHF. At the same time, bisoprolol and nebivolol differing pharmacochemical properties can have a multidirectional effect on the regulatory-adaptive status (RAS).
 Aim. To determine the effect of bisoprolol or nebivolol therapy on the RAS of patients with diastolic CHF on the background of HD III stage.
 Material and methods. The study involved 68 patients with diastolic CHF who were randomized into two groups for treatment with bisoprolol or nebivolol. As part of the combination therapy, patients were administered quinapril was prescribed (13.52.5 mg/day, n=34 and 12.82.8 mg/day, n=34), and if indicated, acetylsalicylic acid, atorvastatin. Initially and after 24 weeks of therapy were carried out: quantitative assessment of RAS, echocardiography, treadmill test, six-minute walking test, subjective assessment of quality of life, determination of the level of N-terminal propeptide of brain natriuretic hormone in blood plasma, daily monitoring of blood pressure.
 Results. Both schemes of combined therapy comparably improved the structural and functional state of the heart, controlled arterial hypertension. In comparison with bisoprolol, nebivolol differed positive impact on RAS, more increased tolerance to physical activity and improved quality of life.
 Conclusion. In patients with diastolic CHF and HD III stage, the use of nebivolol in combination therapy may be preferable due to the positive effect on RAS, in comparison with bisoprolol.

Dedicated breast computed-tomography in women with a personal history of breast cancer: A proof-of-concept study

PurposeTo compare the subjective image quality assessment using B-CT and digital mammography in women with personal history of breast cancer (PHBC). MethodIn this retrospective study 32 patients with PHBC were included. Each patient had undergone a B-CT examination and a previous mammogram in a time interval of less than 18 months between the two examinations. Two radiologists evaluated the two examinations independently with regard to the presence of lesions, BI-RADS classification, level of confidence for the overall exam interpretation, scar evaluation and image quality including image degradation due to clip artifacts. Level of confidence and image quality were assessed using a 5-point Likert scale. A p-value of less than 0.01 was considered statistically significant. ResultsThirty-seven operated and 27 non-operated breasts were included. Confidence for the overall interpretation with B-CT was equal or superior to mammography in 63 cases (98.4 %) for reader 1 and in 58 cases (90.6 %) for reader 2 (p <.001). Confidence for scar evaluation with B-CT was equal or superior to mammography in all cases for reader 1 and in 34 cases (91.9 %) for readers 2 (p <.001). One case with local recurrence in B-CT was identified by both readers and no false positive findings were reported. A moderate to high image degradation due to beam-hardening artifacts has been reported by both readers in 29.4 % of cases due to surgical clips in the B-CT volume. ConclusionsB-CT in patients with PHBC provides high quality images that can be evaluated with confidence equal or superior to mammography.

Subjective assessment of indoor air quality and thermal environment in patient rooms: A survey study of Polish hospitals

The indoor environment of patient rooms should provide adequate conditions for the safe recovery of the patient. However, in clinical standards, the requirements for conditions in standard patient rooms are either omitted or limited to stating the temperature or humidity. Simultaneously, patients in different countries often feel uncomfortable, and the data indicate large discrepancies in patient room thermal conditions across the world.Therefore, this study aimed to determine how patients in Polish hospitals perceive the indoor environment in their rooms, as well as the relationship between individual patient characteristics (gender and age) and feelings about selected elements of the indoor environment, in addition to feelings related to the self-assessment of the impact of the indoor environment on the recovery process.The results of the presented study indicate that the analysed thermal environment elements are essential in patient rooms and should be given appropriate attention. The individual characteristics of patients, including those caused by illness and medication, make it impossible to create a comfortable environment for each patient in a multi-patient room, and solutions and guidelines to support the recovery process of patients should continue to be developed, including solutions that provide opportunities to create a controlled environment around each patient.

Association between older subjective age and poor sleep quality: a population-based study

ABSTRACT Objective To examine the association of subjective age (SA) with sleep quality in an adult population. Methods In the Korean Sleep and Headache Study, 2,349 participants (49.2% men; 48.1 ± 16.4 years old) were interviewed face-to-face using structured questionnaires between September and December 2018. SA was assessed by asking participants their perceived age in years and then compared with their chronological age (CA). Participants were assigned to three groups: feeling younger, feeling their age, and feeling older. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Association between SA and sleep quality was analyzed with multiple linear regression controlling for demographics, psychosocial, and sleep characteristics. Results The group feeling older (n = 404, 17.2%; men, 58.2%; age, 46.5 ± 16.2 years) had worse sleep quality than the groups feeling younger and feeling their age (PSQI score, 4.3 ± 2.7, 3.8 ± 2.4, 3.4 ± 2.1, respectively, p <.001; prevalence of poor sleep quality, 29.0%, 18.4%, 13.5% respectively, p <.001). The association between SA and the PSQI score remained significant after adjusting for confounders (β = 1.05, 95% confidence interval 0.26, 1.83; p <.001). Stratified analyses by sex and CA showed that the association between SA and the PSQI score was significant only in women and in middle-aged and older group (aged 50–79), suggesting that sex and CA modified the association. Conclusion Age perception was associated with self-reported sleep quality, independent of CA. SA may be a useful marker that complements the conventional assessment of subjective sleep quality.

Improvements in image quality after optimization in digital intraoral radiographs

BackgroundDigital intraoral radiographic exposures are optimized largely on the basis of subjective assessment of diagnostic image quality. This study presents an objective approach to optimize radiographic exposure settings for digital intraoral radiographic systems. MethodsSeven size 2 digital intraoral systems were assessed for image quality and determination of optimal exposure following the protocol specified in American National Standard Institute/American Dental Association Standard No. 1094: Quality Assurance for Digital Intra-Oral Radiographic Systems. A ProX radiograph unit (Planmeca) at 63 kVp and 6 mA was used to obtain radiographs of the Dental Digital Quality Assurance phantom. ImageJ software (National Institutes of Health) was used to quantify dynamic range and spatial resolution, and contrast perceptibility was evaluated visually. Optimal exposure is the setting with the maximal contrast perceptibility and spatial resolution while displaying the full dynamic range. After image optimization, a custom phantom consisting of an endodontically prepared tooth was imaged to evaluate the file position relative to the apex for each system. Differences in distances between file position relative to the root apex at the optimal exposure as well as 1 increment above and below were measured. ResultsRadiographic images obtained at the optimal exposure yielded better visualization and more accurate measurements of the file tip relative to the apex. ConclusionsOptimizing radiographic exposures improves image quality and accuracy in clinical decisions. Practical ImplicationsImprovement in image quality and better accuracy in actual distance of the endodontic file to the radiographic apex coupled with complete cleaning, shaping, and obturation of the canal should lead to better endodontic treatment outcomes.

Characterising Psycho-Physiological Responses and Relationships during a Military Field Training Exercise.

Sixty-two Combat Engineer trainees (59 male, 3 female; age: 25.2 ± 7.2 years) wore an ActiGraph GT9X to monitor daily energy expenditure, physical activity, and sleep. Rating of perceived exertion (RPE), sleep quality, and fatigue were measured daily, subjective well-being was reported days 1, 5, 9, 13 and 15. Multi-level models were used for the analysis. Well-being was affected by a combination of variables including workload, subjective sleep quality, sleep duration, and sleep efficiency. RPE and subjective sleep quality were consistently significant parameters within the models of best fit. Perceptions of well-being were lower during the field training when physical workload increased, and sleep decreased. Energy expenditure was comparatively low, while daily sleep duration was consistent with field training literature. Subjective assessments of workload and sleep quality were consistently effective in explaining variations in well-being and represent an efficient approach to monitor training status of personnel.

Application value of T2 fluid-attenuated inversion recovery sequence based on deep learning in static lacunar infarction.

Regular monitoring of static lacunar infarction (SLI) lesions plays an important role in preventing disease development and managing prognosis. Magnetic resonance imaging is one method used to monitor SLI lesions. To evaluate the image quality of the T2 fluid-attenuated inversion recovery (T2-FLAIR) sequence using artificial intelligence-assisted compressed sensing (ACS) in detecting SLI lesions and assess its clinical applicability. A total of 42 patients were prospectively enrolled and scanned by T2-FLAIR. Two independent readers reviewed the images acquired with accelerated modes 1D (acceleration factor 2) and ACS (acceleration factors 2, 3, and 4). The overall image quality and lesion image quality were analyzed, as were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and number of lesions between groups. The subjective assessment of overall brain image quality and lesion image quality was consistent between the two readers. The lesion display quality and the overall image quality were better with the traditional 1D acceleration method than with the ACS accelerated method. There was no significant difference in the SNR of the lacunar infarction in the images between the groups. The CNR of the images with the 1D acceleration mode was significantly lower than that of images with the ACS acceleration mode. Images with the 1D, ACS2, and ACS3 acceleration modes showed no significant differences in terms of detecting lesions but scan time can be reduced by 40% (1D vs. ACS3). ACS acceleration mode can greatly reduce the scan time. In addition, the images have good SNR, high CNR, and strong SLI lesion detection ability.

A survey on visual quality assessment methods for light fields

Unlike traditional cameras, Light Field (LF) cameras are able to capture both the intensity and direction of light rays from the scene. This rich information demands a certain amount of memory and bandwidth for storage and transmission, and to alleviate this requirement, LF content is processed and compressed. These operations often add degradations to the LF content that can affect its visual quality, requiring the use of methods that can measure visual quality as perceived by the end consumer. For this reason, the area of visual quality of immersive media has been gaining a lot of attention. This paper provides a comprehensive survey of state-of-the-art visual quality assessment methods for LF contents. First, we discuss the LF quality datasets that have been introduced, which contain subjective quality scores. Second, we discuss subjective quality assessment methods followed by objective quality assessment methods. Then we present a statistical comparison of a set of objective visual quality assessment methods. Finally, we summarize this survey and present future research demands for LF contents.

Study of Subjective and Objective Quality Assessment of Night-Time Videos

With the widespread usage of video capture devices and social media videos, videos are dominating the multimedia landscape. There is an emerging need for video quality assessment (VQA) that forms the backbone of advanced video systems. Night-time videos play an important role in user capturing, hence being able to accurately assess their quality is critical. However, the characteristics of night-time videos differ from those of general in-capture videos; and VQA algorithms that have been developed for general-purpose videos cannot accurately assess the quality of night-time videos. Research is needed to gain a better understanding of how humans perceive the quality of night-time videos, and use this new understanding to develop reliable VQA algorithms. To this end, we construct a large-scale night-time VQA database, namely Mobile In-capture Night-time Database for Video Quality (MIND-VQ), containing 1181 night-time videos, 435 subjects, and over 130000 opinion scores. We perform thorough analyses to reveal subjective quality assessment behaviors of night-time videos. Furthermore, we propose a new VQA model, namely Visibility-based Night-time Video Quality Assessment Network, VINIA. Spatial and temporal visibility-aware components are characterized to reflect properties of human perception of night-time VQA task. A series of experiments are conducted to compare our VINIA with other existing VQA algorithms using our new MIND-VQ database and other public VQA databases. Experimental results show that our subjective VQA database provides new insights and our new VINIA model achieves superior performance in accessing night-time video quality.

Bright Voice Quality and Fundamental Frequency Variation in Non-binary Speakers

1) To investigate if vocal variation produced by assigned-female-at-birth (AFAB) non-binary people differed from vocal variation produced by cisgender (cis) participants. Cue values produced by non-binary participants were predicted to differ from those values produced by cisgender participants. 2) To determine if previous subjective assessments of bright voice quality in AFAB non-binary participants were quantifiable, and if so, if non-binary and cisgender participants differed in their voice quality production. A quantitative comparative research design. Phonetic and statistical analyses of continuous speech samples produced by AFAB non-binary and cisgender participants. Vocal cues were mean fundamental frequency (F0) and bright voice quality, measured by cepstral peak prominence-smoothed and spectral slope, with speaker gender as the predictor. At the group level, non-binary participants produced intermediate F0 values - significantly lower than the cis women's and significantly higher than the cis men's. Individually, the majority of non-binary participants produced mean F0 in this intermediate range. Non-binary participants produced significantly less negative spectral slope and higher cepstral peak prominence-smoothed, indicative of a brighter, more resonant voice quality. Individual-level results indicated that vocal training and vocal tract physiology did not fully account for the results found. Participants' agency, particularly their motivation to alter vocal output to avoid being misgendered, has an effect on the AFAB non-binary participants' F0 production and potentially their voice quality. The majority of AFAB non-binary participants uniquely produced the cue combination of intermediate F0 and bright voice quality.

What do users care about? Research on user behavior of mobile interactive video advertising

Mobile interactive video advertising is a relatively new type of media. A combination of interactivity and narrative is used to tell the video story to the audience. This study studied in three steps on mobile interactive video advertising to determine the design basis that should be paid attention to. Firstly, the research framework is proposed through expert interview and qualitative coding of the interview text. Secondly, research samples are made through surveys and conference discussions. The samples were designed into 30 types containing various interactive narrative and involvement. Finally, the qualitative results are verified in a quantitative way. The results show that in order to improve the audience's purchase intention, more attention should be paid to interactive narrative, subjective video quality assessment, immersion, satisfaction, and product involvement.

NNCD-IQA: A new neural networks based compressed database for image quality assessment

Objective and subjective quality assessment is still a challenging problem in various image processing tasks. For instance, in the context of image compression, most of the conducted studies have focused on image datasets encoded using standard algorithms such as JPEG and JPEG2000. In this paper, we propose to further investigate the quality assessment issue in the presence of neural networks-based compressed images. More precisely, a new database of compressed images has been firstly built using JPEG2000 standard as well as four recent neural networks based coding schemes. Then, subjective experiments are performed to obtain the mean opinion scores of the generated distorted images. Finally, an extensive evaluation and analysis of objective image quality assessment metrics is achieved. For instance, in addition to conventional and machine learning metrics, we have considered different deep learning based models, which have been trained on our database. The new subjective database with its associated mean opinion scores as well as the learned models are publicly available at https://github.com/zakopz/NNCD-IQA-Database . The obtained results show the interest of deep learning based metrics in the context of neural networks-based compressed images.

Habituation of changed acoustics properties after canal wall down mastoidectomy

PurposeOur objective is to evaluate the effect of habituation on the altered ear canal acoustics after canal wall down mastoidectomy.MethodsA total of 11 participants with single sided dry cavities and normal contralateral ear canals with normal hearing thresholds were included in the study. Filtered sound fragments were created that simulate the different acoustic properties based on the participants Real Ear to Coupler Difference (RECD) of the cavity ear and the contralateral normal ear canal. These filtered sound fragments are presented to the cavity ear canal and the contralateral normal ear canal using inserts earphones. Participants performed a subjective quality assessment of the sound fragments using paired comparison with a seven-point scale (− 3 till + 3).ResultsMean assessment of sound quality revealed the following results; naturalness of sounds of the cavity ear canal is 0.29 (± 1.41; ns) in favour of the filtered sound fragment of the normal ear canal. Mean assessment of sharpness of sounds in the cavity ear canal is 1.55 (± 1.21, p = 0.55) in favour of the filtered sound fragment of the normal ear canal. Overall preference in the cavity ear canal was in favour of the normal ear canal acoustics 0.72 (SD ± 1.54 p = 0.224).ConclusionsPatients with cavity ear canals seem to habituate to their altered ear canal acoustics. Transforming the ear canal acoustics of the cavity ear to normal ear canal acoustics seem to sharpen the incoming sounds. Overall assessment of quality of sound of the normal ear canal acoustics is better than the cavity acoustics.

Subjective and Objective Video Quality Assessment for Windowed-6DoF Synthesized Videos

Video Quality Assessment (VQA) for windowed six Degree of Freedom (windowed-6DoF) synthesized viewpoints is conducive to the development and broadcasting of 6DoF immersive video system. To explore this new field, we propose the subjective and objective VQA studies for windowed-6DoF synthesized videos. Stage one, a pioneering windowed-6DoF synthesized video quality database with compressed distortion, rendering distortion, and viewing path discomfort are presented, in which overall 128 videos are synthesized from four sequences with different distortion combinations. Stage two, a no-reference objective VQA method is proposed. Firstly, the video is converted into one traditional spatio-temporal domain (XY-T domain) and two new spatio-temporal domains (XT-Y and TY-X domains). Secondly, the emerging rendering distortion and viewing path discomfort are measured in the XT-Y and TY-X domains based on their respective characteristic statistical models, and the common compressed distortion is measured in XY-T domain. Thirdly, the image numbers of new domains are accurately determined through optical flow based depth estimation. Finally, the regression model plus weighting strategy is used to obtain the ultimate quality score of windowed-6DoF synthesized video. Experimental results on three synthesized video databases illustrate that the proposed objective NR VQA method has a good performance in evaluating various synthesized videos, compared with other classic and state-of-the-art 2D/3D IQA/VQA metrics.