Perceptual Quality Assessment for Point Clouds:A Survey

A point cloud is considered a promising 3D representation that has achieved wide applications in several fields.However,quality degradation inevitably occurs during its acquisition and generation,communication and transmission,and rendering and display.Therefore,how to accurately perceive the visual quality of point clouds is a meaningful topic.In this survey,we first introduce the point cloud to emphasize the importance of point cloud quality assessment(PCQA).A review of subjective PCQA is followed,including common point cloud distortions,subjective experimental setups and subjective databases.Then we review and compare objective PCQA methods in terms of modelbased and projection-based.Finally,we provide evaluation criteria for objective PCQA methods and compare the performances of various methods across multiple databases.This survey provides an overview of classical methods and recent advances in PCQA.

Performance in the Fundamentals of Laparoscopic Surgery: Does it reflect global rating scales in the Objective Structured Assessment of Technical Skills in porcine laparoscopic surgery?

Objective:To correlate the utility of the Fundamentals of Laparoscopic Surgery(FLS)manual skills program with the Objective Structured Assessment of Technical Skills(OSATS)global rating scale in evaluating operative performance.Methods:The Asian Urological Surgery Training and Educational Group(AUSTEG)Laparoscopic Upper Tract Surgery Course implemented and validated the FLS program for its usage in laparoscopic surgical training.Delegates’basic laparoscopic skills were assessed using three different training models(peg transfer,precision cutting,and intra-corporeal suturing).They also performed live porcine laparoscopic surgery at the same workshop.Live surgery skills were assessed by blinded faculty using the OSATS rating scale.Results:From March 2016 to March 2019,a total of 81 certified urologists participated in the course,with a median of 5 years of post-residency experience.Although differences in task time did not reach statistical significance,those with more surgical experience were visibly faster at completing the peg transfer and intra-corporeal suturing FLS tasks.However,they took longer to complete the precision cutting task than participants with less experience.Overall OSATS scores correlated weakly with all three FLS tasks(peg transfer time:r=0.331,r^(2)=0.110;precision cutting time:r=0.240,r^(2)=0.058;suturing with intracorporeal knot time:r=0.451,r^(2)=0.203).Conclusion:FLS task parameters did not correlate strongly with OSATS globing rating scale performance.Although FLS task models demonstrated strong validity,it is important to assimilate the inconsistencies when benchmarking technical proficiency against real-life operative competence,as evaluated by FLS and OSATS,respectively.

Automated assessment of transthoracic echocardiogram image quality using deep neural networks

Background Standard views in two-dimensional echocardiography are well established but the qualities of acquired images are highly dependent on operator skills and are assessed subjectively.This study was aimed at providing an objective assessment pipeline for echocardiogram image quality by defining a new set of domain-specific quality indicators.Consequently,image quality assessment can thus be automated to enhance clinical measurements,interpretation,and real-time optimization.Methods We developed deep neural networks for the automated assessment of echocardiographic frames that were randomly sampled from 11,262 adult patients.The private echocardiography dataset consists of 33,784 frames,previously acquired between 2010 and 2020.Unlike non-medical images where full-reference metrics can be applied for image quality,echocardiogram's data are highly heterogeneous and requires blind-reference(IQA)metrics.Therefore,deep learning approaches were used to extract the spatiotemporal features and the image's quality indicators were evaluated against the mean absolute error.Our quality indicators encapsulate both anatomical and pathological elements to provide multivariate assessment scores for anatomical visibility,clarity,depth-gain and foreshortedness.Results The model performance accuracy yielded 94.4%,96.8%,96.2%,97.4%for anatomical visibility,clarity,depth-gain and foreshortedness,respectively.The mean model error of 0.375±0.0052 with computational speed of 2.52 ms per frame(real-time performance)was achieved.Conclusion The novel approach offers new insight to the objective assessment of transthoracic echocardiogram image quality and clinical quantification in A4C and PLAX views.It also lays stronger foundations for the operator's guidance system which can leverage the learning curve for the acquisition of optimum quality images during the transthoracic examination.

Patient experience of scar assessment and the use of scar assessment tools during burns rehabilitation:a qualitative study

Background:Scar assessment plays a key role during burns aftercare,to monitor scar remodelling and patients’psychosocial well-being.To aid assessment,subjective scar assessment scales are available that use health-care professionals’and patients’opinions to score scar characteristics.The subjective scales are more widely used in clinical practice over objective scar measures.To date,there is no research that considers patients’views on scar assessment and the role of subjective and objective assessment tools.Therefore,the aim of this qualitative study was to explore patients’perspectives on scar assessment and the utility of scar assessment tools during burns rehabilitation.Methods:Semi-structured interviews were conducted with 10 adult burn patients who were being reviewed in clinic for scarring.Participants were recruited via their clinical care team and research nurses at the Queen Elizabeth Hospital,Birmingham,UK.Topics covered during interview included patient experience of scar assessment,the use of scar assessment tools and discussion surrounding important factors to be addressed when assessing scars.A thematic analysis using the Framework Method was conducted.Results:Participants identified key subthemes that contribute towards the overarching theme of patient-centred scar assessment.These are:patient-led care;continuity in care;learning how to self-manage scarring;and psychological assessment.Links were demonstrated between these subthemes and the remaining themes that describe scar assessment strategies,indicating their potential patient-centred contributions.The subjective opinions of clinicians were found to be valued above the use of subjective or objective scar assessment tools.Scar assessment scales were perceived to be a beneficial method for self-reflection in relation to psychosocial function-ing.However,minimal feedback and review of completed assessment scales led to uncertainty regarding their purpose.Patients perceived objective tools to be of primary use for health-care professionals,though the measures may aid patients’understanding of scar properties.Conclusions:Scar assessment tools should be used to support,rather than replace,health-care professionals’subjective judgements of scarring.Adapting the way in which clinicians introduce and use scar assessment tools,according to patient needs,can support a patient-centred approach to scar assessment.

Network video quality assessment based on fuzzy inference system

The objective assessment method of network video quality is a challenge, because the video quality will be distorted by various factors, including transmission and compression. In order to improve the objective method, an objective assessment method based on fuzzy inference system of Mamdani is proposed. Firstly, six quality parameters are introduced. All the quality parameters are inputted to fuzzy logic controller system. Secondly, the outputs are used as next inputs and inferred by another fuzzy logic controller system to obtain the objective quality of network video. Lastly, the performance of proposed method is validated on four videos with different network environment. Meanwhile this method is compared with other methods. The experimental results show that the proposed method can improve the similarity between subjective and objective assessment.