Innovative Video Diagnostic Equipment for Material Science

Science.gov (United States)

Capuano, G.; Titomanlio, D.; Soellner, W.; Seidel, A.

2012-01-01

Materials science experiments under microgravity increasingly rely on advanced optical systems to determine the physical properties of the samples under investigation. This includes video systems with high spatial and temporal resolution. The acquisition, handling, storage and transmission to ground of the resulting video data are very challenging. Since the available downlink data rate is limited, the capability to compress the video data significantly without compromising the data quality is essential. We report on the development of a Digital Video System (DVS) for EML (Electro Magnetic Levitator) which provides real-time video acquisition, high compression using advanced Wavelet algorithms, storage and transmission of a continuous flow of video with different characteristics in terms of image dimensions and frame rates. The DVS is able to operate with the latest generation of high-performance cameras acquiring high resolution video images up to 4Mpixels@60 fps or high frame rate video images up to about 1000 fps@512x512pixels.

Subjective Video Quality Assessment in H.264/AVC Video Coding Standard

Directory of Open Access Journals (Sweden)

Z. Miličević

2012-11-01

Full Text Available This paper seeks to provide an approach for subjective video quality assessment in the H.264/AVC standard. For this purpose a special software program for the subjective assessment of quality of all the tested video sequences is developed. It was developed in accordance with recommendation ITU-T P.910, since it is suitable for the testing of multimedia applications. The obtained results show that in the proposed selective intra prediction and optimized inter prediction algorithm there is a small difference in picture quality (signal-to-noise ratio between decoded original and modified video sequences.

Subjective video quality comparison of HDTV monitors

Science.gov (United States)

Seo, G.; Lim, C.; Lee, S.; Lee, C.

2009-01-01

HDTV broadcasting services have become widely available. Furthermore, in the upcoming IPTV services, HDTV services are important and quality monitoring becomes an issue, particularly in IPTV services. Consequently, there have been great efforts to develop video quality measurement methods for HDTV. On the other hand, most HDTV programs will be watched on digital TV monitors which include LCD and PDP TV monitors. In general, the LCD and PDP TV monitors have different color characteristics and response times. Furthermore, most commercial TV monitors include post-processing to improve video quality. In this paper, we compare subjective video quality of some commercial HD TV monitors to investigate the impact of monitor type on perceptual video quality. We used the ACR method as a subjective testing method. Experimental results show that the correlation coefficients among the HDTV monitors are reasonable high. However, for some video sequences and impairments, some differences in subjective scores were observed.

Offset Trace-Based Video Quality Evaluation Network Transport

DEFF Research Database (Denmark)

Seeling, P.; Reisslein, M.; Fitzek, Frank

2006-01-01

Video traces contain information about encoded video frames, such as frame sizes and qualities, and provide a convenient method to conduct multimedia networking research. Although wiedely used in networking research, these traces do not allow to determine the video qaulityin an accurate manner...... after networking transport that includes losses and delays. In this work, we provide (i) an overview of frame dependencies that have to be taken into consideration when working with video traces, (ii) an algorithmic approach to combine traditional video traces and offset distortion traces to determine...... the video quality or distortion after lossy network transport, (iii) offset distortion and quality characteristics and (iv) the offset distortion trace format and tools to create offset distortion traces....

Research on quality metrics of wireless adaptive video streaming

Science.gov (United States)

Li, Xuefei

2018-04-01

With the development of wireless networks and intelligent terminals, video traffic has increased dramatically. Adaptive video streaming has become one of the most promising video transmission technologies. For this type of service, a good QoS (Quality of Service) of wireless network does not always guarantee that all customers have good experience. Thus, new quality metrics have been widely studies recently. Taking this into account, the objective of this paper is to investigate the quality metrics of wireless adaptive video streaming. In this paper, a wireless video streaming simulation platform with DASH mechanism and multi-rate video generator is established. Based on this platform, PSNR model, SSIM model and Quality Level model are implemented. Quality Level Model considers the QoE (Quality of Experience) factors such as image quality, stalling and switching frequency while PSNR Model and SSIM Model mainly consider the quality of the video. To evaluate the performance of these QoE models, three performance metrics (SROCC, PLCC and RMSE) which are used to make a comparison of subjective and predicted MOS (Mean Opinion Score) are calculated. From these performance metrics, the monotonicity, linearity and accuracy of these quality metrics can be observed.

Home Video Telemetry vs inpatient telemetry: A comparative study looking at video quality

Directory of Open Access Journals (Sweden)

Sutapa Biswas

Full Text Available Objective: To compare the quality of home video recording with inpatient telemetry (IPT to evaluate our current Home Video Telemetry (HVT practice. Method: To assess our HVT practice, a retrospective comparison of the video quality against IPT was conducted with the latter as the gold standard. A pilot study had been conducted in 2008 on 5 patients.Patients (n = 28 were included in each group over a period of one year.The data was collected from referral spreadsheets, King’s EPR and telemetry archive.Scoring of the events captured was by consensus using two scorers.The variables compared included: visibility of the body part of interest, visibility of eyes, time of event, illumination, contrast, sound quality and picture clarity when amplified to 200%.Statistical evaluation was carried out using Shapiro–Wilk and Chi-square tests. The P-value of ⩽0.05 was considered statistically significant. Results: Significant differences were demonstrated in lighting and contrast between the two groups (HVT performed better in both.Amplified picture quality was slightly better in the HVT group. Conclusion: Video quality of HVT is comparable to IPT, even surpassing IPT in certain aspects such as the level of illumination and contrast. Results were reconfirmed in a larger sample of patients with more variables. Significance: Despite the user and environmental variability in HVT, it looks promising and can be seriously considered as a preferable alternative for patients who may require investigation at locations remote from an EEG laboratory. Keywords: Home Video Telemetry, EEG, Home video monitoring, Video quality

Video-Quality Estimation Based on Reduced-Reference Model Employing Activity-Difference

Science.gov (United States)

Yamada, Toru; Miyamoto, Yoshihiro; Senda, Yuzo; Serizawa, Masahiro

This paper presents a Reduced-reference based video-quality estimation method suitable for individual end-user quality monitoring of IPTV services. With the proposed method, the activity values for individual given-size pixel blocks of an original video are transmitted to end-user terminals. At the end-user terminals, the video quality of a received video is estimated on the basis of the activity-difference between the original video and the received video. Psychovisual weightings and video-quality score adjustments for fatal degradations are applied to improve estimation accuracy. In addition, low-bit-rate transmission is achieved by using temporal sub-sampling and by transmitting only the lower six bits of each activity value. The proposed method achieves accurate video quality estimation using only low-bit-rate original video information (15kbps for SDTV). The correlation coefficient between actual subjective video quality and estimated quality is 0.901 with 15kbps side information. The proposed method does not need computationally demanding spatial and gain-and-offset registrations. Therefore, it is suitable for real-time video-quality monitoring in IPTV services.

Quality and noise measurements in mobile phone video capture

Science.gov (United States)

Petrescu, Doina; Pincenti, John

2011-02-01

The quality of videos captured with mobile phones has become increasingly important particularly since resolutions and formats have reached a level that rivals the capabilities available in the digital camcorder market, and since many mobile phones now allow direct playback on large HDTVs. The video quality is determined by the combined quality of the individual parts of the imaging system including the image sensor, the digital color processing, and the video compression, each of which has been studied independently. In this work, we study the combined effect of these elements on the overall video quality. We do this by evaluating the capture under various lighting, color processing, and video compression conditions. First, we measure full reference quality metrics between encoder input and the reconstructed sequence, where the encoder input changes with light and color processing modifications. Second, we introduce a system model which includes all elements that affect video quality, including a low light additive noise model, ISP color processing, as well as the video encoder. Our experiments show that in low light conditions and for certain choices of color processing the system level visual quality may not improve when the encoder becomes more capable or the compression ratio is reduced.

No-Reference Video Quality Assessment by HEVC Codec Analysis

DEFF Research Database (Denmark)

Huang, Xin; Søgaard, Jacob; Forchhammer, Søren

2015-01-01

This paper proposes a No-Reference (NR) Video Quality Assessment (VQA) method for videos subject to the distortion given by High Efficiency Video Coding (HEVC). The proposed assessment can be performed either as a BitstreamBased (BB) method or as a Pixel-Based (PB). It extracts or estimates...... the transform coefficients, estimates the distortion, and assesses the video quality. The proposed scheme generates VQA features based on Intra coded frames, and then maps features using an Elastic Net to predict subjective video quality. A set of HEVC coded 4K UHD sequences are tested. Results show...... that the quality scores computed by the proposed method are highly correlated with the subjective assessment....

No-Reference Video Quality Assessment using MPEG Analysis

DEFF Research Database (Denmark)

Søgaard, Jacob; Forchhammer, Søren; Korhonen, Jari

2013-01-01

We present a method for No-Reference (NR) Video Quality Assessment (VQA) for decoded video without access to the bitstream. This is achieved by extracting and pooling features from a NR image quality assessment method used frame by frame. We also present methods to identify the video coding...... and estimate the video coding parameters for MPEG-2 and H.264/AVC which can be used to improve the VQA. The analysis differs from most other video coding analysis methods since it is without access to the bitstream. The results show that our proposed method is competitive with other recent NR VQA methods...

No-Reference Video Quality Assessment using Codec Analysis

DEFF Research Database (Denmark)

Søgaard, Jacob; Forchhammer, Søren; Korhonen, Jari

2015-01-01

types of videos, estimating the level of quantization used in the I-frames, and exploiting this information to assess the video quality. In order to do this for H.264/AVC, the distribution of the DCT-coefficients after intra-prediction and deblocking are modeled. To obtain VQA features for H.264/AVC, we......A no-reference video quality assessment (VQA) method is presented for videos distorted by H.264/AVC and MPEG-2. The assessment is performed without access to the bit-stream. Instead we analyze and estimate coefficients based on decoded pixels. The approach involves distinguishing between the two...... propose a novel estimation method of the quantization in H.264/AVC videos without bitstream access, which can also be used for Peak Signalto-Noise Ratio (PSNR) estimation. The results from the MPEG-2 and H.264/AVC analysis are mapped to a perceptual measure of video quality by Support Vector Regression...

Effective Quality-of-Service Renegotiating Schemes for Streaming Video

Directory of Open Access Journals (Sweden)

Song Hwangjun

2004-01-01

Full Text Available This paper presents effective quality-of-service renegotiating schemes for streaming video. The conventional network supporting quality of service generally allows a negotiation at a call setup. However, it is not efficient for the video application since the compressed video traffic is statistically nonstationary. Thus, we consider the network supporting quality-of-service renegotiations during the data transmission and study effective quality-of-service renegotiating schemes for streaming video. The token bucket model, whose parameters are token filling rate and token bucket size, is adopted for the video traffic model. The renegotiating time instants and the parameters are determined by analyzing the statistical information of compressed video traffic. In this paper, two renegotiating approaches, that is, fixed renegotiating interval case and variable renegotiating interval case, are examined. Finally, the experimental results are provided to show the performance of the proposed schemes.

No-Reference Video Quality Assessment Model for Distortion Caused by Packet Loss in the Real-Time Mobile Video Services

Directory of Open Access Journals (Sweden)

Jiarun Song

2014-01-01

Full Text Available Packet loss will make severe errors due to the corruption of related video data. For most video streams, because the predictive coding structures are employed, the transmission errors in one frame will not only cause decoding failure of itself at the receiver side, but also propagate to its subsequent frames along the motion prediction path, which will bring a significant degradation of end-to-end video quality. To quantify the effects of packet loss on video quality, a no-reference objective quality assessment model is presented in this paper. Considering the fact that the degradation of video quality significantly relies on the video content, the temporal complexity is estimated to reflect the varying characteristic of video content, using the macroblocks with different motion activities in each frame. Then, the quality of the frame affected by the reference frame loss, by error propagation, or by both of them is evaluated, respectively. Utilizing a two-level temporal pooling scheme, the video quality is finally obtained. Extensive experimental results show that the video quality estimated by the proposed method matches well with the subjective quality.

Quality-Aware Estimation of Facial Landmarks in Video Sequences

DEFF Research Database (Denmark)

Haque, Mohammad Ahsanul; Nasrollahi, Kamal; Moeslund, Thomas B.

2015-01-01

Face alignment in video is a primitive step for facial image analysis. The accuracy of the alignment greatly depends on the quality of the face image in the video frames and low quality faces are proven to cause erroneous alignment. Thus, this paper proposes a system for quality aware face...... for facial landmark detection. If the face quality is low the proposed system corrects the facial landmarks that are detected by SDM. Depending upon the face velocity in consecutive video frames and face quality measure, two algorithms are proposed for correction of landmarks in low quality faces by using...

Objective video quality assessment method for freeze distortion based on freeze aggregation

Science.gov (United States)

Watanabe, Keishiro; Okamoto, Jun; Kurita, Takaaki

2006-01-01

With the development of the broadband network, video communications such as videophone, video distribution, and IPTV services are beginning to become common. In order to provide these services appropriately, we must manage them based on subjective video quality, in addition to designing a network system based on it. Currently, subjective quality assessment is the main method used to quantify video quality. However, it is time-consuming and expensive. Therefore, we need an objective quality assessment technology that can estimate video quality from video characteristics effectively. Video degradation can be categorized into two types: spatial and temporal. Objective quality assessment methods for spatial degradation have been studied extensively, but methods for temporal degradation have hardly been examined even though it occurs frequently due to network degradation and has a large impact on subjective quality. In this paper, we propose an objective quality assessment method for temporal degradation. Our approach is to aggregate multiple freeze distortions into an equivalent freeze distortion and then derive the objective video quality from the equivalent freeze distortion. Specifically, our method considers the total length of all freeze distortions in a video sequence as the length of the equivalent single freeze distortion. In addition, we propose a method using the perceptual characteristics of short freeze distortions. We verified that our method can estimate the objective video quality well within the deviation of subjective video quality.

No-reference pixel based video quality assessment for HEVC decoded video

DEFF Research Database (Denmark)

Huang, Xin; Søgaard, Jacob; Forchhammer, Søren

2017-01-01

the quantization step used in the Intra coding is estimated. We map the obtained HEVC features using an Elastic Net to predict subjective video quality scores, Mean Opinion Scores (MOS). The performance is verified on a dataset consisting of HEVC coded 4 K UHD (resolution equal to 3840 x 2160) video sequences...

Video profile monitor diagnostic system for GTA

International Nuclear Information System (INIS)

Sandoval, D.P.; Garcia, R.C.; Gilpatrick, J.D.; Johnson, K.F.; Shinas, M.A.; Wright, R.; Yuan, V.; Zander, M.E.

1992-01-01

This paper describes a video diagnostic system used to measure the beam profile and position of the Ground Test Accelerator 2.5-MeV H - ion beam as it exits the intermediate matching section. Inelastic collisions between H-ions and residual nitrogen to fluoresce. The resulting light is captured through transport optics by an intensified CCD camera and is digitized. Real-time beam-profile images are displayed and stored for detailed analysis. Analyzed data showing resolutions for both position and profile measurements will also be presented

Overview video diagnostics for the W7-X stellarator

Energy Technology Data Exchange (ETDEWEB)

Kocsis, G., E-mail: kocsis.gabor@wigner.mta.hu [Wigner RCP, RMI, Konkoly Thege 29-33, H-1121 Budapest (Hungary); Baross, T. [Wigner RCP, RMI, Konkoly Thege 29-33, H-1121 Budapest (Hungary); Biedermann, C. [Max-Planck-Institute for Plasma Physics, 17491 Greifswald (Germany); Bodnár, G.; Cseh, G.; Ilkei, T. [Wigner RCP, RMI, Konkoly Thege 29-33, H-1121 Budapest (Hungary); König, R.; Otte, M. [Max-Planck-Institute for Plasma Physics, 17491 Greifswald (Germany); Szabolics, T.; Szepesi, T.; Zoletnik, S. [Wigner RCP, RMI, Konkoly Thege 29-33, H-1121 Budapest (Hungary)

2015-10-15

Considering the requirements of the newly built Wendelstein 7-X stellarator a ten-channel overview video diagnostic system was developed and is presently under installation. The system covering the whole torus interior can be used not only to observe the plasma but also to detect irregular operational events which are dangerous for the stellarator itself and to send automatic warning for the machine safety. The ten tangential AEQ ports used by the diagnostic remain under atmospheric pressure, the vacuum/air interface is at the front window located at the plasma side of the AEQ port. The optical vacuum window is protected by a cooled pinhole. The Sensor Module (SM) of the intelligent camera (EDICAM) – developed especially for this purpose – is located directly behind the vacuum window. EDICAM is designed to simultaneously record several regions of interest of its CMOS sensor with different frame rate and to detect various predefined events in real time. The air cooled SM is fixed by a docking mechanism which can preserve the pointing of the view. EDICAM can withstand the magnetic field (∼3 T), the neutron and gamma fluxes expected in the AEQ port. In order to adopt the new features of the video diagnostics system both control and data acquisition and visualization and data processing softwares are developed.

Overview video diagnostics for the W7-X stellarator

International Nuclear Information System (INIS)

Kocsis, G.; Baross, T.; Biedermann, C.; Bodnár, G.; Cseh, G.; Ilkei, T.; König, R.; Otte, M.; Szabolics, T.; Szepesi, T.; Zoletnik, S.

2015-01-01

Considering the requirements of the newly built Wendelstein 7-X stellarator a ten-channel overview video diagnostic system was developed and is presently under installation. The system covering the whole torus interior can be used not only to observe the plasma but also to detect irregular operational events which are dangerous for the stellarator itself and to send automatic warning for the machine safety. The ten tangential AEQ ports used by the diagnostic remain under atmospheric pressure, the vacuum/air interface is at the front window located at the plasma side of the AEQ port. The optical vacuum window is protected by a cooled pinhole. The Sensor Module (SM) of the intelligent camera (EDICAM) – developed especially for this purpose – is located directly behind the vacuum window. EDICAM is designed to simultaneously record several regions of interest of its CMOS sensor with different frame rate and to detect various predefined events in real time. The air cooled SM is fixed by a docking mechanism which can preserve the pointing of the view. EDICAM can withstand the magnetic field (∼3 T), the neutron and gamma fluxes expected in the AEQ port. In order to adopt the new features of the video diagnostics system both control and data acquisition and visualization and data processing softwares are developed.

Adaptive testing for video quality assessment

NARCIS (Netherlands)

Menkovski, V.; Exarchakos, G.; Liotta, A.; Damásio, M.J.; Cardoso, G.; Quico, C.; Geerts, D.

2011-01-01

Optimizing the Quality of Experience and avoiding under or over provisioning in video delivery services requires understanding of how different resources affect the perceived quality. The utility of resources, such as bit-rate, is directly calculated by proportioningthe improvement in quality over

An Energy-Efficient and High-Quality Video Transmission Architecture in Wireless Video-Based Sensor Networks

Directory of Open Access Journals (Sweden)

Yasaman Samei

2008-08-01

Full Text Available Technological progress in the fields of Micro Electro-Mechanical Systems (MEMS and wireless communications and also the availability of CMOS cameras, microphones and small-scale array sensors, which may ubiquitously capture multimedia content from the field, have fostered the development of low-cost limited resources Wireless Video-based Sensor Networks (WVSN. With regards to the constraints of videobased sensor nodes and wireless sensor networks, a supporting video stream is not easy to implement with the present sensor network protocols. In this paper, a thorough architecture is presented for video transmission over WVSN called Energy-efficient and high-Quality Video transmission Architecture (EQV-Architecture. This architecture influences three layers of communication protocol stack and considers wireless video sensor nodes constraints like limited process and energy resources while video quality is preserved in the receiver side. Application, transport, and network layers are the layers in which the compression protocol, transport protocol, and routing protocol are proposed respectively, also a dropping scheme is presented in network layer. Simulation results over various environments with dissimilar conditions revealed the effectiveness of the architecture in improving the lifetime of the network as well as preserving the video quality.

An Energy-Efficient and High-Quality Video Transmission Architecture in Wireless Video-Based Sensor Networks.

Science.gov (United States)

Aghdasi, Hadi S; Abbaspour, Maghsoud; Moghadam, Mohsen Ebrahimi; Samei, Yasaman

2008-08-04

Technological progress in the fields of Micro Electro-Mechanical Systems (MEMS) and wireless communications and also the availability of CMOS cameras, microphones and small-scale array sensors, which may ubiquitously capture multimedia content from the field, have fostered the development of low-cost limited resources Wireless Video-based Sensor Networks (WVSN). With regards to the constraints of videobased sensor nodes and wireless sensor networks, a supporting video stream is not easy to implement with the present sensor network protocols. In this paper, a thorough architecture is presented for video transmission over WVSN called Energy-efficient and high-Quality Video transmission Architecture (EQV-Architecture). This architecture influences three layers of communication protocol stack and considers wireless video sensor nodes constraints like limited process and energy resources while video quality is preserved in the receiver side. Application, transport, and network layers are the layers in which the compression protocol, transport protocol, and routing protocol are proposed respectively, also a dropping scheme is presented in network layer. Simulation results over various environments with dissimilar conditions revealed the effectiveness of the architecture in improving the lifetime of the network as well as preserving the video quality.

Quality Assessment of Compressed Video for Automatic License Plate Recognition

DEFF Research Database (Denmark)

Ukhanova, Ann; Støttrup-Andersen, Jesper; Forchhammer, Søren

2014-01-01

Definition of video quality requirements for video surveillance poses new questions in the area of quality assessment. This paper presents a quality assessment experiment for an automatic license plate recognition scenario. We explore the influence of the compression by H.264/AVC and H.265/HEVC s...... recognition in our study has a behavior similar to human recognition, allowing the use of the same mathematical models. We furthermore propose an application of one of the models for video surveillance systems......Definition of video quality requirements for video surveillance poses new questions in the area of quality assessment. This paper presents a quality assessment experiment for an automatic license plate recognition scenario. We explore the influence of the compression by H.264/AVC and H.265/HEVC...... standards on the recognition performance. We compare logarithmic and logistic functions for quality modeling. Our results show that a logistic function can better describe the dependence of recognition performance on the quality for both compression standards. We observe that automatic license plate...

Crowdsourcing based subjective quality assessment of adaptive video streaming

DEFF Research Database (Denmark)

Shahid, M.; Søgaard, Jacob; Pokhrel, J.

2014-01-01

In order to cater for user’s quality of experience (QoE) re- quirements, HTTP adaptive streaming (HAS) based solutions of video services have become popular recently. User QoE feedback can be instrumental in improving the capabilities of such services. Perceptual quality experiments that involve...... humans are considered to be the most valid method of the as- sessment of QoE. Besides lab-based subjective experiments, crowdsourcing based subjective assessment of video quality is gaining popularity as an alternative method. This paper presents insights into a study that investigates perceptual pref......- erences of various adaptive video streaming scenarios through crowdsourcing based subjective quality assessment....

Study of Temporal Effects on Subjective Video Quality of Experience.

Science.gov (United States)

Bampis, Christos George; Zhi Li; Moorthy, Anush Krishna; Katsavounidis, Ioannis; Aaron, Anne; Bovik, Alan Conrad

2017-11-01

HTTP adaptive streaming is being increasingly deployed by network content providers, such as Netflix and YouTube. By dividing video content into data chunks encoded at different bitrates, a client is able to request the appropriate bitrate for the segment to be played next based on the estimated network conditions. However, this can introduce a number of impairments, including compression artifacts and rebuffering events, which can severely impact an end-user's quality of experience (QoE). We have recently created a new video quality database, which simulates a typical video streaming application, using long video sequences and interesting Netflix content. Going beyond previous efforts, the new database contains highly diverse and contemporary content, and it includes the subjective opinions of a sizable number of human subjects regarding the effects on QoE of both rebuffering and compression distortions. We observed that rebuffering is always obvious and unpleasant to subjects, while bitrate changes may be less obvious due to content-related dependencies. Transient bitrate drops were preferable over rebuffering only on low complexity video content, while consistently low bitrates were poorly tolerated. We evaluated different objective video quality assessment algorithms on our database and found that objective video quality models are unreliable for QoE prediction on videos suffering from both rebuffering events and bitrate changes. This implies the need for more general QoE models that take into account objective quality models, rebuffering-aware information, and memory. The publicly available video content as well as metadata for all of the videos in the new database can be found at http://live.ece.utexas.edu/research/LIVE_NFLXStudy/nflx_index.html.

Video profile monitor diagnostic system for GTA

International Nuclear Information System (INIS)

Sandovil, D.P.; Garcia, R.C.; Gilpatrick, J.D.; Johnson, K.F.; Shinas, M.A.; Wright, R.; Yuan, V.; Zander, M.E.

1992-01-01

This paper describes a video diagnostic system used to measure the beam profile and position of the Ground Test Accelerator 2.5 MeV H - ion beam as it exits the intermediate matching section. Inelastic collisions between H - ions and residual nitrogen in the vacuum chamber cause the nitrogen to fluoresce. The resulting light is captured through transport optics by an intensified CCD camera and is digitized. Real-time beam profile images are displayed and stored for detailed analysis. Analyzed data showing resolutions for both position and profile measurements will also be presented. (Author) 5 refs., 7 figs

Is perception of quality more important than technical quality in patient video cases?

Science.gov (United States)

Roland, Damian; Matheson, David; Taub, Nick; Coats, Tim; Lakhanpaul, Monica

2015-08-13

The use of video cases to demonstrate key signs and symptoms in patients (patient video cases or PVCs) is a rapidly expanding field. The aims of this study were to evaluate whether the technical quality, or judgement of quality, of a video clip influences a paediatrician's judgment on acuity of the case and assess the relationship between perception of quality and the technical quality of a selection of video clips. Participants (12 senior consultant paediatricians attending an examination workshop) individually categorised 28 PVCs into one of 3 possible acuities and then described the quality of the image seen. The PVCs had been converted into four different technical qualities (differing bit rates ranging from excellent to low quality). Participants' assessment of quality and the actual industry standard of the PVC were independent (333 distinct observations, spearmans rho = 0.0410, p = 0.4564). Agreement between actual acuity and participants' judgement was generally good at higher acuities but moderate at medium/low acuities of illness (overall correlation 0.664). Perception of the quality of the clip was related to correct assignment of acuity regardless of the technical quality of the clip (number of obs = 330, z = 2.07, p = 0.038). It is important to benchmark PVCs prior to use in learning resources as experts may not agree on the information within, or quality of, the clip. It appears, although PVCs may be beneficial in a pedagogical context, the perception of quality of clip may be an important determinant of an expert's decision making.

Applicability of Existing Objective Metrics of Perceptual Quality for Adaptive Video Streaming

DEFF Research Database (Denmark)

Søgaard, Jacob; Krasula, Lukás; Shahid, Muhammad

2016-01-01

Objective video quality metrics are designed to estimate the quality of experience of the end user. However, these objective metrics are usually validated with video streams degraded under common distortion types. In the presented work, we analyze the performance of published and known full......-reference and noreference quality metrics in estimating the perceived quality of adaptive bit-rate video streams knowingly out of scope. Experimental results indicate not surprisingly that state of the art objective quality metrics overlook the perceived degradations in the adaptive video streams and perform poorly...

Deep learning for quality assessment in live video streaming

NARCIS (Netherlands)

Torres Vega, M.; Mocanu, D.C.; Famaey, J.; Stavrou, S.; Liotta, A.

Video content providers put stringent requirements on the quality assessment methods realized on their services. They need to be accurate, real-time, adaptable to new content, and scalable as the video set grows. In this letter, we introduce a novel automated and computationally efficient video

Predictive no-reference assessment of video quality

NARCIS (Netherlands)

Torres Vega, M.; Mocanu, D.C.; Stavrou, S.; Liotta, A.

2017-01-01

Among the various means to evaluate the quality of video streams, light-weight No-Reference (NR) methods have low computation and may be executed on thin clients. Thus, these methods would be perfect candidates in cases of real-time quality assessment, automated quality control and in adaptive

Quality of Experience management for video streams : the case of Skype

NARCIS (Netherlands)

Liotta, A.; Druda, L.; Exarchakos, G.; Menkovski, V.; Khalil, I.

2012-01-01

With the widespread adoption of mobile Internet, the process of streaming video has become varied and complex. A diversity of factors affect the way we perceive quality in video streaming (also known as 'quality of experience', or QoE), involving far more than the individual video and network

Towards Video Quality Metrics Based on Colour Fractal Geometry

Directory of Open Access Journals (Sweden)

Richard Noël

2010-01-01

Full Text Available Vision is a complex process that integrates multiple aspects of an image: spatial frequencies, topology and colour. Unfortunately, so far, all these elements were independently took into consideration for the development of image and video quality metrics, therefore we propose an approach that blends together all of them. Our approach allows for the analysis of the complexity of colour images in the RGB colour space, based on the probabilistic algorithm for calculating the fractal dimension and lacunarity. Given that all the existing fractal approaches are defined only for gray-scale images, we extend them to the colour domain. We show how these two colour fractal features capture the multiple aspects that characterize the degradation of the video signal, based on the hypothesis that the quality degradation perceived by the user is directly proportional to the modification of the fractal complexity. We claim that the two colour fractal measures can objectively assess the quality of the video signal and they can be used as metrics for the user-perceived video quality degradation and we validated them through experimental results obtained for an MPEG-4 video streaming application; finally, the results are compared against the ones given by unanimously-accepted metrics and subjective tests.

The art of assessing quality for images and video

International Nuclear Information System (INIS)

Deriche, M.

2011-01-01

The early years of this century have witnessed a tremendous growth in the use of digital multimedia data for di?erent communication applications. Researchers from around the world are spending substantial research efforts in developing techniques for improving the appearance of images/video. However, as we know, preserving high quality is a challenging task. Images are subject to distortions during acquisition, compression, transmission, analysis, and reconstruction. For this reason, the research area focusing on image and video quality assessment has attracted a lot of attention in recent years. In particular, compression applications and other multimedia applications need powerful techniques for evaluating quality objectively without human interference. This tutorial will cover the di?erent faces of image quality assessment. We will motivate the need for robust image quality assessment techniques, then discuss the main algorithms found in the literature with a critical perspective. We will present the di?erent metrics used for full reference, reduced reference and no reference applications. We will then discuss the difference between image and video quality assessment. In all of the above, we will take a critical approach to explain which metric can be used for which application. Finally we will discuss the different approaches to analyze the performance of image/video quality metrics, and end the tutorial with some perspectives on newly introduced metrics and their potential applications.

Quality of YouTube TM videos on dental implants.

Science.gov (United States)

Abukaraky, A; Hamdan, A-A; Ameera, M-N; Nasief, M; Hassona, Y

2018-07-01

Patients search YouTube for health-care information. To examine what YouTube offers patients seeking information on dental implants, and to evaluate the quality of provided information. A systematic search of YouTube for videos containing information on dental implants was performed using the key words Dental implant and Tooth replacement. Videos were examined by two senior Oral and Maxillofacial Surgery residents who were trained and calibrated to perform the search. Initial assessment was performed to exclude non- English language videos, duplicate videos, conference lectures, and irrelevant videos. Included videos were analyzed with regard to demographics and content's usefulness. Information for patients available from the American Academy of Implant Dentistry, European Association of Osseointegration, and British Society of Restorative Dentistry were used for benchmarking. A total of 117 videos were analyzed. The most commonly discussed topics were related to procedures involved in dental implantology (76.1%, n=89), and to the indications for dental implants (58.1%, n=78). The mean usefulness score of videos was poor (6.02 ±4.7 [range 0-21]), and misleading content was common (30.1% of videos); mainly in topics related to prognosis and maintenance of dental implants. Most videos (83.1%, n=97) failed to mention the source of information presented in the video or where to find more about dental implants. Information about dental implants on YouTube is limited in quality and quantity. YouTube videos can have a potentially important role in modulating patients attitude and treatment decision regarding dental implants.

Bandwidth allocation for video under quality of service constraints

CERN Document Server

Anjum, Bushra

2014-01-01

We present queueing-based algorithms to calculate the bandwidth required for a video stream so that the three main Quality of Service constraints, i.e., end-to-end delay, jitter and packet loss, are ensured. Conversational and streaming video-based applications are becoming a major part of the everyday Internet usage. The quality of these applications (QoS), as experienced by the user, depends on three main metrics of the underlying network, namely, end-to-end delay, jitter and packet loss. These metrics are, in turn, directly related to the capacity of the links that the video traffic trave

Objective video quality measure for application to tele-echocardiography.

Science.gov (United States)

Moore, Peter Thomas; O'Hare, Neil; Walsh, Kevin P; Ward, Neil; Conlon, Niamh

2008-08-01

Real-time tele-echocardiography is widely used to remotely diagnose or exclude congenital heart defects. Cost effective technical implementation is realised using low-bandwidth transmission systems and lossy compression (videoconferencing) schemes. In our study, DICOM video sequences were converted to common multimedia formats, which were then, compressed using three lossy compression algorithms. We then applied a digital (multimedia) video quality metric (VQM) to determine objectively a value for degradation due to compression. Three levels of compression were simulated by varying system bandwidth and compared to a subjective assessment of video clip quality by three paediatric cardiologists with more than 5 years of experience.

Quality assurance testing on video games : The importance and impact of a misunderstood industry

OpenAIRE

Ruuska, Essi

2015-01-01

The aim of this research was to provide a more holistic insight of the video game quality assurance industry to video game industry professionals and prospective employees in order to promote the importance and impact of quality assurance testing in video games. The motive for this thesis came from the author's work experience in video game quality assurance testing, and from realizing how little is known about the industry. The research question was defined as 'what is video game quality ass...

Non-intrusive Packet-Layer Model for Monitoring Video Quality of IPTV Services

Science.gov (United States)

Yamagishi, Kazuhisa; Hayashi, Takanori

Developing a non-intrusive packet-layer model is required to passively monitor the quality of experience (QoE) during service. We propose a packet-layer model that can be used to estimate the video quality of IPTV using quality parameters derived from transmitted packet headers. The computational load of the model is lighter than that of the model that takes video signals and/or video-related bitstream information such as motion vectors as input. This model is applicable even if the transmitted bitstream information is encrypted because it uses transmitted packet headers rather than bitstream information. For developing the model, we conducted three extensive subjective quality assessments for different encoders and decoders (codecs), and video content. Then, we modeled the subjective video quality assessment characteristics based on objective features affected by coding and packet loss. Finally, we verified the model's validity by applying our model to unknown data sets different from training data sets used above.

Teaching Surgical Procedures with Movies: Tips for High-quality Video Clips

OpenAIRE

Jacquemart, Mathieu; Bouletreau, Pierre; Breton, Pierre; Mojallal, Ali; Sigaux, Nicolas

2016-01-01

Summary: Video must now be considered as a precious tool for learning surgery. However, the medium does present production challenges, and currently, quality movies are not always accessible. We developed a series of 7 surgical videos and made them available on a publicly accessible internet website. Our videos have been viewed by thousands of people worldwide. High-quality educational movies must respect strategic and technical points to be reliable.

Teaching Surgical Procedures with Movies: Tips for High-quality Video Clips.

Science.gov (United States)

Jacquemart, Mathieu; Bouletreau, Pierre; Breton, Pierre; Mojallal, Ali; Sigaux, Nicolas

2016-09-01

Video must now be considered as a precious tool for learning surgery. However, the medium does present production challenges, and currently, quality movies are not always accessible. We developed a series of 7 surgical videos and made them available on a publicly accessible internet website. Our videos have been viewed by thousands of people worldwide. High-quality educational movies must respect strategic and technical points to be reliable.

Subjective Quality Assessment of H.264/AVC Video Streaming with Packet Losses

Directory of Open Access Journals (Sweden)

Naccari Matteo

2011-01-01

Full Text Available Research in the field of video quality assessment relies on the availability of subjective scores, collected by means of experiments in which groups of people are asked to rate the quality of video sequences. The availability of subjective scores is fundamental to enable validation and comparative benchmarking of the objective algorithms that try to predict human perception of video quality by automatically analyzing the video sequences, in a way to support reproducible and reliable research results. In this paper, a publicly available database of subjective quality scores and corrupted video sequences is described. The scores refer to 156 sequences at CIF and 4CIF spatial resolutions, encoded with H.264/AVC and corrupted by simulating the transmission over an error-prone network. The subjective evaluation has been performed by 40 subjects at the premises of two academic institutions, in standard-compliant controlled environments. In order to support reproducible research in the field of full-reference, reduced-reference, and no-reference video quality assessment algorithms, both the uncompressed files and the H.264/AVC bitstreams, as well as the packet loss patterns, have been made available to the research community.

Operation quality assessment model for video conference system

Science.gov (United States)

Du, Bangshi; Qi, Feng; Shao, Sujie; Wang, Ying; Li, Weijian

2018-01-01

Video conference system has become an important support platform for smart grid operation and management, its operation quality is gradually concerning grid enterprise. First, the evaluation indicator system covering network, business and operation maintenance aspects was established on basis of video conference system's operation statistics. Then, the operation quality assessment model combining genetic algorithm with regularized BP neural network was proposed, which outputs operation quality level of the system within a time period and provides company manager with some optimization advice. The simulation results show that the proposed evaluation model offers the advantages of fast convergence and high prediction accuracy in contrast with regularized BP neural network, and its generalization ability is superior to LM-BP neural network and Bayesian BP neural network.

Quality-Based Backlight Optimization for Video Playback on Handheld Devices

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Liang Cheng

2007-01-01

Full Text Available For a typical handheld device, the backlight accounts for a significant percentage of the total energy consumption (e.g., around 30% for a Compaq iPAQ 3650. Substantial energy savings can be achieved by dynamically adapting backlight intensity levels on such low-power portable devices. In this paper, we analyze the characteristics of video streaming services and propose a cross-layer optimization scheme called quality adapted backlight scaling (QABS to achieve backlight energy savings for video playback applications on handheld devices. Specifically, we present a fast algorithm to optimize backlight dimming while keeping the degradation in image quality to a minimum so that the overall service quality is close to a specified threshold. Additionally, we propose two effective techniques to prevent frequent backlight switching, which negatively affects user perception of video. Our initial experimental results indicate that the energy used for backlight is significantly reduced, while the desired quality is satisfied. The proposed algorithms can be realized in real time.

PSQM-based RR and NR video quality metrics

Science.gov (United States)

Lu, Zhongkang; Lin, Weisi; Ong, Eeping; Yang, Xiaokang; Yao, Susu

2003-06-01

This paper presents a new and general concept, PQSM (Perceptual Quality Significance Map), to be used in measuring the visual distortion. It makes use of the selectivity characteristic of HVS (Human Visual System) that it pays more attention to certain area/regions of visual signal due to one or more of the following factors: salient features in image/video, cues from domain knowledge, and association of other media (e.g., speech or audio). PQSM is an array whose elements represent the relative perceptual-quality significance levels for the corresponding area/regions for images or video. Due to its generality, PQSM can be incorporated into any visual distortion metrics: to improve effectiveness or/and efficiency of perceptual metrics; or even to enhance a PSNR-based metric. A three-stage PQSM estimation method is also proposed in this paper, with an implementation of motion, texture, luminance, skin-color and face mapping. Experimental results show the scheme can improve the performance of current image/video distortion metrics.

Modeling the time--varying subjective quality of HTTP video streams with rate adaptations.

Science.gov (United States)

Chen, Chao; Choi, Lark Kwon; de Veciana, Gustavo; Caramanis, Constantine; Heath, Robert W; Bovik, Alan C

2014-05-01

Newly developed hypertext transfer protocol (HTTP)-based video streaming technologies enable flexible rate-adaptation under varying channel conditions. Accurately predicting the users' quality of experience (QoE) for rate-adaptive HTTP video streams is thus critical to achieve efficiency. An important aspect of understanding and modeling QoE is predicting the up-to-the-moment subjective quality of a video as it is played, which is difficult due to hysteresis effects and nonlinearities in human behavioral responses. This paper presents a Hammerstein-Wiener model for predicting the time-varying subjective quality (TVSQ) of rate-adaptive videos. To collect data for model parameterization and validation, a database of longer duration videos with time-varying distortions was built and the TVSQs of the videos were measured in a large-scale subjective study. The proposed method is able to reliably predict the TVSQ of rate adaptive videos. Since the Hammerstein-Wiener model has a very simple structure, the proposed method is suitable for online TVSQ prediction in HTTP-based streaming.

The role of optical flow in automated quality assessment of full-motion video

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Harguess, Josh; Shafer, Scott; Marez, Diego

2017-09-01

In real-world video data, such as full-motion-video (FMV) taken from unmanned vehicles, surveillance systems, and other sources, various corruptions to the raw data is inevitable. This can be due to the image acquisition process, noise, distortion, and compression artifacts, among other sources of error. However, we desire methods to analyze the quality of the video to determine whether the underlying content of the corrupted video can be analyzed by humans or machines and to what extent. Previous approaches have shown that motion estimation, or optical flow, can be an important cue in automating this video quality assessment. However, there are many different optical flow algorithms in the literature, each with their own advantages and disadvantages. We examine the effect of the choice of optical flow algorithm (including baseline and state-of-the-art), on motionbased automated video quality assessment algorithms.

Weighted-MSE based on saliency map for assessing video quality of H.264 video streams

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Boujut, H.; Benois-Pineau, J.; Hadar, O.; Ahmed, T.; Bonnet, P.

2011-01-01

Human vision system is very complex and has been studied for many years specifically for purposes of efficient encoding of visual, e.g. video content from digital TV. There have been physiological and psychological evidences which indicate that viewers do not pay equal attention to all exposed visual information, but only focus on certain areas known as focus of attention (FOA) or saliency regions. In this work, we propose a novel based objective quality assessment metric, for assessing the perceptual quality of decoded video sequences affected by transmission errors and packed loses. The proposed method weights the Mean Square Error (MSE), Weighted-MSE (WMSE), according to the calculated saliency map at each pixel. Our method was validated trough subjective quality experiments.

3D Scan-Based Wavelet Transform and Quality Control for Video Coding

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Parisot Christophe

2003-01-01

Full Text Available Wavelet coding has been shown to achieve better compression than DCT coding and moreover allows scalability. 2D DWT can be easily extended to 3D and thus applied to video coding. However, 3D subband coding of video suffers from two drawbacks. The first is the amount of memory required for coding large 3D blocks; the second is the lack of temporal quality due to the sequence temporal splitting. In fact, 3D block-based video coders produce jerks. They appear at blocks temporal borders during video playback. In this paper, we propose a new temporal scan-based wavelet transform method for video coding combining the advantages of wavelet coding (performance, scalability with acceptable reduced memory requirements, no additional CPU complexity, and avoiding jerks. We also propose an efficient quality allocation procedure to ensure a constant quality over time.

Balancing Attended and Global Stimuli in Perceived Video Quality Assessment

DEFF Research Database (Denmark)

You, Junyong; Korhonen, Jari; Perkis, Andrew

2011-01-01

. This paper proposes a quality model based on the late attention selection theory, assuming that the video quality is perceived via two mechanisms: global and local quality assessment. First we model several visual features influencing the visual attention in quality assessment scenarios to derive......The visual attention mechanism plays a key role in the human perception system and it has a significant impact on our assessment of perceived video quality. In spite of receiving less attention from the viewers, unattended stimuli can still contribute to the understanding of the visual content...... an attention map using appropriate fusion techniques. The global quality assessment as based on the assumption that viewers allocate their attention equally to the entire visual scene, is modeled by four carefully designed quality features. By employing these same quality features, the local quality model...

Video Quality Assessment Using Spatio-Velocity Contrast Sensitivity Function

Science.gov (United States)

Hirai, Keita; Tumurtogoo, Jambal; Kikuchi, Ayano; Tsumura, Norimichi; Nakaguchi, Toshiya; Miyake, Yoichi

Due to the development and popularization of high-definition televisions, digital video cameras, Blu-ray discs, digital broadcasting, IP television and so on, it plays an important role to identify and quantify video quality degradations. In this paper, we propose SV-CIELAB which is an objective video quality assessment (VQA) method using a spatio-velocity contrast sensitivity function (SV-CSF). In SV-CIELAB, motion information in videos is effectively utilized for filtering unnecessary information in the spatial frequency domain. As the filter to apply videos, we used the SV-CSF. It is a modulation transfer function of the human visual system, and consists of the relationship among contrast sensitivities, spatial frequencies and velocities of perceived stimuli. In the filtering process, the SV-CSF cannot be directly applied in the spatial frequency domain because spatial coordinate information is required when using velocity information. For filtering by the SV-CSF, we obtain video frames separated in spatial frequency domain. By using velocity information, the separated frames with limited spatial frequencies are weighted by contrast sensitivities in the SV-CSF model. In SV-CIELAB, the criteria are obtained by calculating image differences between filtered original and distorted videos. For the validation of SV-CIELAB, subjective evaluation experiments were conducted. The subjective experimental results were compared with SV-CIELAB and the conventional VQA methods such as CIELAB color difference, Spatial-CIELAB, signal to noise ratio and so on. From the experimental results, it was shown that SV-CIELAB is a more efficient VQA method than the conventional methods.

On the definition of adapted audio/video profiles for high-quality video calling services over LTE/4G

Science.gov (United States)

Ndiaye, Maty; Quinquis, Catherine; Larabi, Mohamed Chaker; Le Lay, Gwenael; Saadane, Hakim; Perrine, Clency

2014-01-01

During the last decade, the important advances and widespread availability of mobile technology (operating systems, GPUs, terminal resolution and so on) have encouraged a fast development of voice and video services like video-calling. While multimedia services have largely grown on mobile devices, the generated increase of data consumption is leading to the saturation of mobile networks. In order to provide data with high bit-rates and maintain performance as close as possible to traditional networks, the 3GPP (The 3rd Generation Partnership Project) worked on a high performance standard for mobile called Long Term Evolution (LTE). In this paper, we aim at expressing recommendations related to audio and video media profiles (selection of audio and video codecs, bit-rates, frame-rates, audio and video formats) for a typical video-calling services held over LTE/4G mobile networks. These profiles are defined according to targeted devices (smartphones, tablets), so as to ensure the best possible quality of experience (QoE). Obtained results indicate that for a CIF format (352 x 288 pixels) which is usually used for smartphones, the VP8 codec provides a better image quality than the H.264 codec for low bitrates (from 128 to 384 kbps). However sequences with high motion, H.264 in slow mode is preferred. Regarding audio, better results are globally achieved using wideband codecs offering good quality except for opus codec (at 12.2 kbps).

Impairment-Factor-Based Audiovisual Quality Model for IPTV: Influence of Video Resolution, Degradation Type, and Content Type

Directory of Open Access Journals (Sweden)

Garcia MN

2011-01-01

Full Text Available This paper presents an audiovisual quality model for IPTV services. The model estimates the audiovisual quality of standard and high definition video as perceived by the user. The model is developed for applications such as network planning and packet-layer quality monitoring. It mainly covers audio and video compression artifacts and impairments due to packet loss. The quality tests conducted for model development demonstrate a mutual influence of the perceived audio and video quality, and the predominance of the video quality for the overall audiovisual quality. The balance between audio quality and video quality, however, depends on the content, the video format, and the audio degradation type. The proposed model is based on impairment factors which quantify the quality-impact of the different degradations. The impairment factors are computed from parameters extracted from the bitstream or packet headers. For high definition video, the model predictions show a correlation with unknown subjective ratings of 95%. For comparison, we have developed a more classical audiovisual quality model which is based on the audio and video qualities and their interaction. Both quality- and impairment-factor-based models are further refined by taking the content-type into account. At last, the different model variants are compared with modeling approaches described in the literature.

Quality control in diagnostic radiology - patient dosimetry

Energy Technology Data Exchange (ETDEWEB)

Prlic, I; Radalj, Z; Brumen, V; Cerovac, H [Institute for Medical Research and Occupational Health, Laboratory for Radiation Protection and Dosimetry, Zagreb (Croatia); Gladic, J [Institute for Physics, Laboratory for Solid State Physics, Zagreb (Croatia); Tercek, V [Clinical Hospital Sisters of Mercy, Health Physics Department, Zagreb (Croatia)

1997-12-31

In order to establish the Quality Criteria for diagnostic radiographic images in the radiology departments in Republic of Croatia we have started the several Quality Control projects on the field. The measurements are performed according to some methodology recommendations in our law but the methodology, measurement principles, measurement equipment, phantoms, measurable parameters for the good use by radiographers, statistical and numerical evaluation, dosimetric philosophy etc. where first recognized as a private/or group hazard of each person involved in the procedure of evaluation of diagnostic radiology images/diagnosis. The important quality elements of the imaging process are: the diagnostic quality of the radiographic image, the radiation dose to the patient and the choice of the radiographic technique. This depends on the x-ray unit (tube) radiation quality, image processing quality and final image evaluation quality. In this paper we will show how the Quality Control measurements can be easily connected to the dose delivered to the patient for the known diagnostic procedure and how this can be used by radiographers in their daily work. The reproducibility of the x-ray generator was checked before the service calibration and after the service calibration. The table of kV dependence and output dose per mAs was calculated and the ESD (entrance surface dose) was measured/calculated for the specific diagnostic procedure. After the phantom calculation were made and the dose prediction for the given procedure was done, measurements were done on the patients (digital dosemeters, TLD and film dosemeter combinations). We are claiming that there is no need to measure each patient if the proper Quality Control measurements are done and the proper table of ESD for each particular x-ray tube in diagnostic departments is calculated for the radiographers daily use. (author). 1 example, 1 fig., 13 refs.

Algorithm for Video Summarization of Bronchoscopy Procedures

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Leszczuk Mikołaj I

2011-12-01

Full Text Available Abstract Background The duration of bronchoscopy examinations varies considerably depending on the diagnostic and therapeutic procedures used. It can last more than 20 minutes if a complex diagnostic work-up is included. With wide access to videobronchoscopy, the whole procedure can be recorded as a video sequence. Common practice relies on an active attitude of the bronchoscopist who initiates the recording process and usually chooses to archive only selected views and sequences. However, it may be important to record the full bronchoscopy procedure as documentation when liability issues are at stake. Furthermore, an automatic recording of the whole procedure enables the bronchoscopist to focus solely on the performed procedures. Video recordings registered during bronchoscopies include a considerable number of frames of poor quality due to blurry or unfocused images. It seems that such frames are unavoidable due to the relatively tight endobronchial space, rapid movements of the respiratory tract due to breathing or coughing, and secretions which occur commonly in the bronchi, especially in patients suffering from pulmonary disorders. Methods The use of recorded bronchoscopy video sequences for diagnostic, reference and educational purposes could be considerably extended with efficient, flexible summarization algorithms. Thus, the authors developed a prototype system to create shortcuts (called summaries or abstracts of bronchoscopy video recordings. Such a system, based on models described in previously published papers, employs image analysis methods to exclude frames or sequences of limited diagnostic or education value. Results The algorithm for the selection or exclusion of specific frames or shots from video sequences recorded during bronchoscopy procedures is based on several criteria, including automatic detection of "non-informative", frames showing the branching of the airways and frames including pathological lesions. Conclusions

A randomized controlled trial of an educational video to improve quality of bowel preparation for colonoscopy.

Science.gov (United States)

Park, Jin-Seok; Kim, Min Su; Kim, HyungKil; Kim, Shin Il; Shin, Chun Ho; Lee, Hyun Jung; Lee, Won Seop; Moon, Soyoung

2016-06-17

High-quality bowel preparation is necessary for colonoscopy. A few studies have been conducted to investigate improvement in bowel preparation quality through patient education. However, the effect of patient education on bowel preparation has not been well studied. A randomized and prospective study was conducted. All patients received regular instruction for bowel preparation during a pre-colonoscopy visit. Those scheduled for colonoscopy were randomly assigned to view an educational video instruction (video group) on the day before the colonoscopy, or to a non-video (control) group. Qualities of bowel preparation using the Ottawa Bowel Preparation Quality scale (Ottawa score) were compared between the video and non-video groups. In addition, factors associated with poor bowel preparation were investigated. A total of 502 patients were randomized, 250 to the video group and 252 to the non-video group. The video group exhibited better bowel preparation (mean Ottawa total score: 3.03 ± 1.9) than the non-video group (4.21 ± 1.9; P educational video could improve the quality of bowel preparation in comparison with standard preparation method. Clinical Research Information Service KCT0001836 . The date of registration: March, 08(th), 2016, Retrospectively registered.

Recurrent and Dynamic Models for Predicting Streaming Video Quality of Experience.

Science.gov (United States)

Bampis, Christos G; Li, Zhi; Katsavounidis, Ioannis; Bovik, Alan C

2018-07-01

Streaming video services represent a very large fraction of global bandwidth consumption. Due to the exploding demands of mobile video streaming services, coupled with limited bandwidth availability, video streams are often transmitted through unreliable, low-bandwidth networks. This unavoidably leads to two types of major streaming-related impairments: compression artifacts and/or rebuffering events. In streaming video applications, the end-user is a human observer; hence being able to predict the subjective Quality of Experience (QoE) associated with streamed videos could lead to the creation of perceptually optimized resource allocation strategies driving higher quality video streaming services. We propose a variety of recurrent dynamic neural networks that conduct continuous-time subjective QoE prediction. By formulating the problem as one of time-series forecasting, we train a variety of recurrent neural networks and non-linear autoregressive models to predict QoE using several recently developed subjective QoE databases. These models combine multiple, diverse neural network inputs, such as predicted video quality scores, rebuffering measurements, and data related to memory and its effects on human behavioral responses, using them to predict QoE on video streams impaired by both compression artifacts and rebuffering events. Instead of finding a single time-series prediction model, we propose and evaluate ways of aggregating different models into a forecasting ensemble that delivers improved results with reduced forecasting variance. We also deploy appropriate new evaluation metrics for comparing time-series predictions in streaming applications. Our experimental results demonstrate improved prediction performance that approaches human performance. An implementation of this work can be found at https://github.com/christosbampis/NARX_QoE_release.

Quality Variation Control for Three-Dimensional Wavelet-Based Video Coders

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Vidhya Seran

2007-02-01

Full Text Available The fluctuation of quality in time is a problem that exists in motion-compensated-temporal-filtering (MCTF- based video coding. The goal of this paper is to design a solution for overcoming the distortion fluctuation challenges faced by wavelet-based video coders. We propose a new technique for determining the number of bits to be allocated to each temporal subband in order to minimize the fluctuation in the quality of the reconstructed video. Also, the wavelet filter properties are explored to design suitable scaling coefficients with the objective of smoothening the temporal PSNR. The biorthogonal 5/3 wavelet filter is considered in this paper and experimental results are presented for 2D+t and t+2D MCTF wavelet coders.

Quality Variation Control for Three-Dimensional Wavelet-Based Video Coders

Directory of Open Access Journals (Sweden)

Seran Vidhya

2007-01-01

Full Text Available The fluctuation of quality in time is a problem that exists in motion-compensated-temporal-filtering (MCTF- based video coding. The goal of this paper is to design a solution for overcoming the distortion fluctuation challenges faced by wavelet-based video coders. We propose a new technique for determining the number of bits to be allocated to each temporal subband in order to minimize the fluctuation in the quality of the reconstructed video. Also, the wavelet filter properties are explored to design suitable scaling coefficients with the objective of smoothening the temporal PSNR. The biorthogonal 5/3 wavelet filter is considered in this paper and experimental results are presented for 2D+t and t+2D MCTF wavelet coders.

A no-reference image and video visual quality metric based on machine learning

Science.gov (United States)

Frantc, Vladimir; Voronin, Viacheslav; Semenishchev, Evgenii; Minkin, Maxim; Delov, Aliy

2018-04-01

The paper presents a novel visual quality metric for lossy compressed video quality assessment. High degree of correlation with subjective estimations of quality is due to using of a convolutional neural network trained on a large amount of pairs video sequence-subjective quality score. We demonstrate how our predicted no-reference quality metric correlates with qualitative opinion in a human observer study. Results are shown on the EVVQ dataset with comparison existing approaches.

Evaluating the Accuracy and Quality of the Information in Kyphosis Videos Shared on YouTube.

Science.gov (United States)

Erdem, Mehmet Nuri; Karaca, Sinan

2018-04-16

A quality-control YouTube-based study using the recognized quality scoring systems. In this study, our aim was to confirm the accuracy and quality of the information in kyphosis videos shared on YouTube. The Internet is a widely and increasingly used source for obtaining medical information both by patients and clinicians. YouTube, in particular, manifests itself as a leading source with its ease of access to information and visual advantage for Internet users. The first 50 videos returned by the YouTube search engine in response to 'kyphosis' keyword query were included in the study and categorized under seven and six groups, based on their source and content. The popularity of the videos were evaluated with a new index called the video power index (VPI). The quality, educational quality and accuracy of the source of information were measured using the JAMA score, Global Quality Score (GQS) and Kyphosis Specific Score (KSS). Videos had a mean duration of 397 seconds and a mean number of views of 131,644, with a total viewing number of 6,582,221. The source (uploader) in 36% of the videos was a trainer and the content in 46% of the videos was exercise training. 72% of the videos were about postural kyphosis. Videos had a mean JAMA score of 1.36 (range: 1 to 4), GQS of 1.68 (range: 1 to 5) and KSS of 3.02 (range:0 to 32). The academic group had the highest scores and the lowest VPIs. Online information on kyphosis is low quality and its contents are of unknown source and accuracy. In order to keep the balance in sharing the right information with the patient, clinicians should possess knowledge about the online information related to their field, and should contribute to the development of optimal medical videos. 3.

Nonintrusive Method Based on Neural Networks for Video Quality of Experience Assessment

Directory of Open Access Journals (Sweden)

Diego José Luis Botia Valderrama

2016-01-01

Full Text Available The measurement and evaluation of the QoE (Quality of Experience have become one of the main focuses in the telecommunications to provide services with the expected quality for their users. However, factors like the network parameters and codification can affect the quality of video, limiting the correlation between the objective and subjective metrics. The above increases the complexity to evaluate the real quality of video perceived by users. In this paper, a model based on artificial neural networks such as BPNNs (Backpropagation Neural Networks and the RNNs (Random Neural Networks is applied to evaluate the subjective quality metrics MOS (Mean Opinion Score and the PSNR (Peak Signal Noise Ratio, SSIM (Structural Similarity Index Metric, VQM (Video Quality Metric, and QIBF (Quality Index Based Frame. The proposed model allows establishing the QoS (Quality of Service based in the strategy Diffserv. The metrics were analyzed through Pearson’s and Spearman’s correlation coefficients, RMSE (Root Mean Square Error, and outliers rate. Correlation values greater than 90% were obtained for all the evaluated metrics.

Video quality measure for mobile IPTV service

Science.gov (United States)

Kim, Wonjun; Kim, Changick

2008-08-01

Mobile IPTV is a multimedia service based on wireless networks with interactivity and mobility. Under mobile IPTV scenarios, people can watch various contents whenever they want and even deliver their request to service providers through the network. However, the frequent change of the wireless channel bandwidth may hinder the quality of service. In this paper, we propose an objective video quality measure (VQM) for mobile IPTV services, which is focused on the jitter measurement. Jitter is the result of frame repetition during the delay and one of the most severe impairments in the video transmission via mobile channels. We first employ YUV color space to compute the duration and occurrences of jitter and the motion activity. Then the VQM is modeled by the combination of these three factors and the result of subjective assessment. Since the proposed VQM is based on no-reference (NR) model, it can be applied for real-time applications. Experimental results show that the proposed VQM highly correlates to subjective evaluation.

Quality metric for spherical panoramic video

Science.gov (United States)

Zakharchenko, Vladyslav; Choi, Kwang Pyo; Park, Jeong Hoon

2016-09-01

Virtual reality (VR)/ augmented reality (AR) applications allow users to view artificial content of a surrounding space simulating presence effect with a help of special applications or devices. Synthetic contents production is well known process form computer graphics domain and pipeline has been already fixed in the industry. However emerging multimedia formats for immersive entertainment applications such as free-viewpoint television (FTV) or spherical panoramic video require different approaches in content management and quality assessment. The international standardization on FTV has been promoted by MPEG. This paper is dedicated to discussion of immersive media distribution format and quality estimation process. Accuracy and reliability of the proposed objective quality estimation method had been verified with spherical panoramic images demonstrating good correlation results with subjective quality estimation held by a group of experts.

Amplitude Integrated Electroencephalography Compared With Conventional Video EEG for Neonatal Seizure Detection: A Diagnostic Accuracy Study.

Science.gov (United States)

Rakshasbhuvankar, Abhijeet; Rao, Shripada; Palumbo, Linda; Ghosh, Soumya; Nagarajan, Lakshmi

2017-08-01

This diagnostic accuracy study compared the accuracy of seizure detection by amplitude-integrated electroencephalography with the criterion standard conventional video EEG in term and near-term infants at risk of seizures. Simultaneous recording of amplitude-integrated EEG (2-channel amplitude-integrated EEG with raw trace) and video EEG was done for 24 hours for each infant. Amplitude-integrated EEG was interpreted by a neonatologist; video EEG was interpreted by a neurologist independently. Thirty-five infants were included in the analysis. In the 7 infants with seizures on video EEG, there were 169 seizure episodes on video EEG, of which only 57 were identified by amplitude-integrated EEG. Amplitude-integrated EEG had a sensitivity of 33.7% for individual seizure detection. Amplitude-integrated EEG had an 86% sensitivity for detection of babies with seizures; however, it was nonspecific, in that 50% of infants with seizures detected by amplitude-integrated EEG did not have true seizures by video EEG. In conclusion, our study suggests that amplitude-integrated EEG is a poor screening tool for neonatal seizures.

Frame Rate versus Spatial Quality: Which Video Characteristics Do Matter?

DEFF Research Database (Denmark)

Korhonen, Jari; Reiter, Ulrich; Ukhanova, Ann

2013-01-01

and temporal quality levels. We also propose simple yet powerful metrics for characterizing spatial and temporal properties of a video sequence, and demonstrate how these metrics can be applied for evaluating the relative impact of spatial and temporal quality on the perceived overall quality....

Open-source telemedicine platform for wireless medical video communication.

Science.gov (United States)

Panayides, A; Eleftheriou, I; Pantziaris, M

2013-01-01

An m-health system for real-time wireless communication of medical video based on open-source software is presented. The objective is to deliver a low-cost telemedicine platform which will allow for reliable remote diagnosis m-health applications such as emergency incidents, mass population screening, and medical education purposes. The performance of the proposed system is demonstrated using five atherosclerotic plaque ultrasound videos. The videos are encoded at the clinically acquired resolution, in addition to lower, QCIF, and CIF resolutions, at different bitrates, and four different encoding structures. Commercially available wireless local area network (WLAN) and 3.5G high-speed packet access (HSPA) wireless channels are used to validate the developed platform. Objective video quality assessment is based on PSNR ratings, following calibration using the variable frame delay (VFD) algorithm that removes temporal mismatch between original and received videos. Clinical evaluation is based on atherosclerotic plaque ultrasound video assessment protocol. Experimental results show that adequate diagnostic quality wireless medical video communications are realized using the designed telemedicine platform. HSPA cellular networks provide for ultrasound video transmission at the acquired resolution, while VFD algorithm utilization bridges objective and subjective ratings.

Open-Source Telemedicine Platform for Wireless Medical Video Communication

Science.gov (United States)

Panayides, A.; Eleftheriou, I.; Pantziaris, M.

2013-01-01

An m-health system for real-time wireless communication of medical video based on open-source software is presented. The objective is to deliver a low-cost telemedicine platform which will allow for reliable remote diagnosis m-health applications such as emergency incidents, mass population screening, and medical education purposes. The performance of the proposed system is demonstrated using five atherosclerotic plaque ultrasound videos. The videos are encoded at the clinically acquired resolution, in addition to lower, QCIF, and CIF resolutions, at different bitrates, and four different encoding structures. Commercially available wireless local area network (WLAN) and 3.5G high-speed packet access (HSPA) wireless channels are used to validate the developed platform. Objective video quality assessment is based on PSNR ratings, following calibration using the variable frame delay (VFD) algorithm that removes temporal mismatch between original and received videos. Clinical evaluation is based on atherosclerotic plaque ultrasound video assessment protocol. Experimental results show that adequate diagnostic quality wireless medical video communications are realized using the designed telemedicine platform. HSPA cellular networks provide for ultrasound video transmission at the acquired resolution, while VFD algorithm utilization bridges objective and subjective ratings. PMID:23573082

Open-Source Telemedicine Platform for Wireless Medical Video Communication

Directory of Open Access Journals (Sweden)

A. Panayides

2013-01-01

Full Text Available An m-health system for real-time wireless communication of medical video based on open-source software is presented. The objective is to deliver a low-cost telemedicine platform which will allow for reliable remote diagnosis m-health applications such as emergency incidents, mass population screening, and medical education purposes. The performance of the proposed system is demonstrated using five atherosclerotic plaque ultrasound videos. The videos are encoded at the clinically acquired resolution, in addition to lower, QCIF, and CIF resolutions, at different bitrates, and four different encoding structures. Commercially available wireless local area network (WLAN and 3.5G high-speed packet access (HSPA wireless channels are used to validate the developed platform. Objective video quality assessment is based on PSNR ratings, following calibration using the variable frame delay (VFD algorithm that removes temporal mismatch between original and received videos. Clinical evaluation is based on atherosclerotic plaque ultrasound video assessment protocol. Experimental results show that adequate diagnostic quality wireless medical video communications are realized using the designed telemedicine platform. HSPA cellular networks provide for ultrasound video transmission at the acquired resolution, while VFD algorithm utilization bridges objective and subjective ratings.

GoPro Hero Cameras for Creation of a Three-Dimensional, Educational, Neurointerventional Video.

Science.gov (United States)

Park, Min S; Brock, Andrea; Mortimer, Vance; Taussky, Philipp; Couldwell, William T; Quigley, Edward

2017-10-01

Neurointerventional education relies on an apprenticeship model, with the trainee observing and participating in procedures with the guidance of a mentor. While educational videos are becoming prevalent in surgical cases, there is a dearth of comparable educational material for trainees in neurointerventional programs. We sought to create a high-quality, three-dimensional video of a routine diagnostic cerebral angiogram for use as an educational tool. A diagnostic cerebral angiogram was recorded using two GoPro HERO 3+ cameras with the Dual HERO System to capture the proceduralist's hands during the case. This video was edited with recordings from the video monitors to create a real-time three-dimensional video of both the actions of the neurointerventionalist and the resulting wire/catheter movements. The final edited video, in either two or three dimensions, can serve as another instructional tool for the training of residents and/or fellows. Additional videos can be created in a similar fashion of more complicated neurointerventional cases. The GoPro HERO 3+ camera and Dual HERO System can be used to create educational videos of neurointerventional procedures.

Quality assurance programme for isotope diagnostic laboratories

International Nuclear Information System (INIS)

Krasznai, Istvan

1987-01-01

Quality assurance systems are suggested to be introduced in laboratories, in accordance with the recommendations of IAEA and WHO, taking local circumstances into consideration. It is emphasized that a quantitative enhancement of work must not endanger its quality; diagnostic information must be undistorted, reproducible, and gathered with the minimum of radiation burden. National authorities are requested to strengthen their supervision. Recommendations for quality assurance methods are given for medical isotope diagnostic laboratories. (author)

Capturing and displaying microscopic images used in medical diagnostics and forensic science using 4K video resolution - an application in higher education.

Science.gov (United States)

Maier, Hans; de Heer, Gert; Ortac, Ajda; Kuijten, Jan

2015-11-01

To analyze, interpret and evaluate microscopic images, used in medical diagnostics and forensic science, video images for educational purposes were made with a very high resolution of 4096 × 2160 pixels (4K), which is four times as many pixels as High-Definition Video (1920 × 1080 pixels). The unprecedented high resolution makes it possible to see details that remain invisible to any other video format. The images of the specimens (blood cells, tissue sections, hair, fibre, etc.) are recorded using a 4K video camera which is attached to a light microscope. After processing, this resulted in very sharp and highly detailed images. This material was then used in education for classroom discussion. Spoken explanation by experts in the field of medical diagnostics and forensic science was also added to the high-resolution video images to make it suitable for self-study. © 2015 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.

Computed Quality Assessment of MPEG4-compressed DICOM Video Data.

Science.gov (United States)

Frankewitsch, Thomas; Söhnlein, Sven; Müller, Marcel; Prokosch, Hans-Ulrich

2005-01-01

Digital Imaging and Communication in Medicine (DICOM) has become one of the most popular standards in medicine. This standard specifies the exact procedures in which digital images are exchanged between devices, either using a network or storage medium. Sources for images vary; therefore there exist definitions for the exchange for CR, CT, NMR, angiography, sonography and so on. With its spreading, with the increasing amount of sources included, data volume is increasing, too. This affects storage and traffic. While for long-time storage data compression is generally not accepted at the moment, there are many situations where data compression is possible: Telemedicine for educational purposes (e.g. students at home using low speed internet connections), presentations with standard-resolution video projectors, or even the supply on wards combined receiving written findings. DICOM comprises compression: for still image there is JPEG, for video MPEG-2 is adopted. Within the last years MPEG-2 has been evolved to MPEG-4, which squeezes data even better, but the risk of significant errors increases, too. Within the last years effects of compression have been analyzed for entertainment movies, but these are not comparable to videos of physical examinations (e.g. echocardiography). In medical videos an individual image plays a more important role. Erroneous single images affect total quality even more. Additionally, the effect of compression can not be generalized from one test series to all videos. The result depends strongly on the source. Some investigations have been presented, where different MPEG-4 algorithms compressed videos have been compared and rated manually. But they describe only the results in an elected testbed. In this paper some methods derived from video rating are presented and discussed for an automatically created quality control for the compression of medical videos, primary stored in DICOM containers.

Investigating the quality of video consultations performed using fourth generation (4G) mobile telecommunications.

Science.gov (United States)

Caffery, Liam J; Smith, Anthony C

2015-09-01

The use of fourth-generation (4G) mobile telecommunications to provide real-time video consultations were investigated in this study with the aims of determining if 4G is a suitable telecommunications technology; and secondly, to identify if variation in perceived audio and video quality were due to underlying network performance. Three patient end-points that used 4G Internet connections were evaluated. Consulting clinicians recorded their perception of audio and video quality using the International Telecommunications Union scales during clinics with these patient end-points. These scores were used to calculate a mean opinion score (MOS). The network performance metrics were obtained for each session and the relationships between these metrics and the session's quality scores were tested. Clinicians scored the quality of 50 hours of video consultations, involving 36 clinic sessions. The MOS for audio was 4.1 ± 0.62 and the MOS for video was 4.4 ± 0.22. Image impairment and effort to listen were also rated favourably. There was no correlation between audio or video quality and the network metrics of packet loss or jitter. These findings suggest that 4G networks are an appropriate telecommunication technology to deliver real-time video consultations. Variations in quality scores observed during this study were not explained by the packet loss and jitter in the underlying network. Before establishing a telemedicine service, the performance of the 4G network should be assessed at the location of the proposed service. This is due to known variability in performance of 4G networks. © The Author(s) 2015.

High-resolution X-ray television and high-resolution video recorders

International Nuclear Information System (INIS)

Haendle, J.; Horbaschek, H.; Alexandrescu, M.

1977-01-01

The improved transmission properties of the high-resolution X-ray television chain described here make it possible to transmit more information per television image. The resolution in the fluoroscopic image, which is visually determined, depends on the dose rate and the inertia of the television pick-up tube. This connection is discussed. In the last few years, video recorders have been increasingly used in X-ray diagnostics. The video recorder is a further quality-limiting element in X-ray television. The development of function patterns of high-resolution magnetic video recorders shows that this quality drop may be largely overcome. The influence of electrical band width and number of lines on the resolution in the X-ray television image stored is explained in more detail. (orig.) [de

The influence of motion quality on responses towards video playback stimuli

Directory of Open Access Journals (Sweden)

Emma Ware

2015-07-01

Full Text Available Visual motion, a critical cue in communication, can be manipulated and studied using video playback methods. A primary concern for the video playback researcher is the degree to which objects presented on video appear natural to the non-human subject. Here we argue that the quality of motion cues on video, as determined by the video's image presentation rate (IPR, are of particular importance in determining a subject's social response behaviour. We present an experiment testing the effect of variations in IPR on pigeon (Columbia livia response behaviour towards video images of courting opposite sex partners. Male and female pigeons were presented with three video playback stimuli, each containing a different social partner. Each stimulus was then modified to appear at one of three IPRs: 15, 30 or 60 progressive (p frames per second. The results showed that courtship behaviour became significantly longer in duration as IPR increased. This finding implies that the IPR significantly affects the perceived quality of motion cues impacting social behaviour. In males we found that the duration of courtship also depended on the social partner viewed and that this effect interacted with the effects of IPR on behaviour. Specifically, the effect of social partner reached statistical significance only when the stimuli were displayed at 60 p, demonstrating the potential for erroneous results when insufficient IPRs are used. In addition to demonstrating the importance of IPR in video playback experiments, these findings help to highlight and describe the role of visual motion processing in communication behaviour.

Video quality of 3G videophones for telephone cardiopulmonary resuscitation.

Science.gov (United States)

Tränkler, Uwe; Hagen, Oddvar; Horsch, Alexander

2008-01-01

We simulated a cardiopulmonary resuscitation (CPR) scene with a manikin and used two 3G videophones on the caller's side to transmit video to a laptop PC. Five observers (two doctors with experience in emergency medicine and three paramedics) evaluated the video. They judged whether the manikin was breathing and whether they would give advice for CPR; they also graded the confidence of their decision-making. Breathing was only visible from certain orientations of the videophones, at distances below 150 cm with good illumination and a still background. Since the phones produced a degradation in colours and shadows, detection of breathing mainly depended on moving contours. Low camera positioning produced better results than having the camera high up. Darkness, shaking of the camera and a moving background made detection of breathing almost impossible. The video from the two 3G videophones that were tested was of sufficient quality for telephone CPR provided that camera orientation, distance, illumination and background were carefully chosen. Thus it seems possible to use 3G videophones for emergency calls involving CPR. However, further studies on the required video quality in different scenarios are necessary.

Concerns of Quality and Safety in Public Domain Surgical Education Videos: An Assessment of the Critical View of Safety in Frequently Used Laparoscopic Cholecystectomy Videos.

Science.gov (United States)

Deal, Shanley B; Alseidi, Adnan A

2017-12-01

Online videos are among the most common resources for case preparation. Using crowd sourcing, we evaluated the relationship between operative quality and viewing characteristics of online laparoscopic cholecystectomy videos. We edited 160 online videos of laparoscopic cholecystectomy to 60 seconds or less. Crowd workers (CW) rated videos using Global Objective Assessment of Laparoscopic Skills (GOALS), the critical view of safety (CVS) criteria, and assigned overall pass/fail ratings if CVS was achieved; linear mixed effects models derived average ratings. Views, likes, dislikes, subscribers, and country were recorded for subset analysis of YouTube videos. Spearman correlation coefficient (SCC) assessed correlation between performance measures. One video (0.06%) achieved a passing CVS score of ≥5; 23%, ≥4; 44%, ≥3; 79%, ≥2; and 100% ≥1. Pass/fail ratings correlated to CVS, SCC 0.95 (p quality. The average CVS and GOALS scores were no different for videos with >20,000 views (22%) compared with those with online surgical videos of LC. Favorable characteristics, such as number of views or likes, do not translate to higher quality. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Constructing a no-reference H.264/AVC bitstream-based video quality metric using genetic programming-based symbolic regression

OpenAIRE

Staelens, Nicolas; Deschrijver, Dirk; Vladislavleva, E; Vermeulen, Brecht; Dhaene, Tom; Demeester, Piet

2013-01-01

In order to ensure optimal quality of experience toward end users during video streaming, automatic video quality assessment becomes an important field-of-interest to video service providers. Objective video quality metrics try to estimate perceived quality with high accuracy and in an automated manner. In traditional approaches, these metrics model the complex properties of the human visual system. More recently, however, it has been shown that machine learning approaches can also yield comp...

No-Reference Video Quality Assessment Based on Statistical Analysis in 3D-DCT Domain.

Science.gov (United States)

Li, Xuelong; Guo, Qun; Lu, Xiaoqiang

2016-05-13

It is an important task to design models for universal no-reference video quality assessment (NR-VQA) in multiple video processing and computer vision applications. However, most existing NR-VQA metrics are designed for specific distortion types which are not often aware in practical applications. A further deficiency is that the spatial and temporal information of videos is hardly considered simultaneously. In this paper, we propose a new NR-VQA metric based on the spatiotemporal natural video statistics (NVS) in 3D discrete cosine transform (3D-DCT) domain. In the proposed method, a set of features are firstly extracted based on the statistical analysis of 3D-DCT coefficients to characterize the spatiotemporal statistics of videos in different views. These features are used to predict the perceived video quality via the efficient linear support vector regression (SVR) model afterwards. The contributions of this paper are: 1) we explore the spatiotemporal statistics of videos in 3DDCT domain which has the inherent spatiotemporal encoding advantage over other widely used 2D transformations; 2) we extract a small set of simple but effective statistical features for video visual quality prediction; 3) the proposed method is universal for multiple types of distortions and robust to different databases. The proposed method is tested on four widely used video databases. Extensive experimental results demonstrate that the proposed method is competitive with the state-of-art NR-VQA metrics and the top-performing FR-VQA and RR-VQA metrics.

Management of speech and video telephony quality in heterogeneous wireless networks

CERN Document Server

Lewcio, Błażej

2014-01-01

This book shows how networking research and quality engineering can be combined to successfully manage the transmission quality when speech and video telephony is delivered in heterogeneous wireless networks. Nomadic use of services requires intelligent management of ongoing transmission, and to make the best of available resources many fundamental trade-offs must be considered. Network coverage versus throughput and reliability of a connection is one key aspect, efficiency versus robustness of signal compression is another. However, to successfully manage services, user-perceived Quality of Experience (QoE) in heterogeneous networks must be known, and the perception of quality changes must be understood.  These issues are addressed in this book, in particular focusing on the perception of quality changes due to switching between diverse networks, speech and video codecs, and encoding bit rates during active calls.

A time-varying subjective quality model for mobile streaming videos with stalling events

Science.gov (United States)

Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C.

2015-09-01

Over-the-top mobile video streaming is invariably influenced by volatile network conditions which cause playback interruptions (stalling events), thereby impairing users' quality of experience (QoE). Developing models that can accurately predict users' QoE could enable the more efficient design of quality-control protocols for video streaming networks that reduce network operational costs while still delivering high-quality video content to the customers. Existing objective models that predict QoE are based on global video features, such as the number of stall events and their lengths, and are trained and validated on a small pool of ad hoc video datasets, most of which are not publicly available. The model we propose in this work goes beyond previous models as it also accounts for the fundamental effect that a viewer's recent level of satisfaction or dissatisfaction has on their overall viewing experience. In other words, the proposed model accounts for and adapts to the recency, or hysteresis effect caused by a stall event in addition to accounting for the lengths, frequency of occurrence, and the positions of stall events - factors that interact in a complex way to affect a user's QoE. On the recently introduced LIVE-Avvasi Mobile Video Database, which consists of 180 distorted videos of varied content that are afflicted solely with over 25 unique realistic stalling events, we trained and validated our model to accurately predict the QoE, attaining standout QoE prediction performance.

Participation in interdisciplinary meetings on genetic diagnostics (NGS)

NARCIS (Netherlands)

Koole, Tom; van Burgsteden, Lotte; Harms, Paulien; van Diemen, Cleo C; van Langen, Irene M

2017-01-01

Diagnostics using next generation sequencing (NGS) requires high-quality interdisciplinary collaboration. In order to gain insight into this crucial collaborative process, we made video recordings of a new multidisciplinary team at work in the clinical genetics department of the University Medical

Quality assurance, quality control and quality audit in diagnostic radiology

International Nuclear Information System (INIS)

Vassileva, J.

2009-01-01

Full text:The lecture aims to present contemporary view of quality assurance in X-Ray diagnosis and its practical realization in Bulgaria. In the lecture the concepts of quality assurance, quality control and clinical audit will be defined and their scope will be considered. An answer of the following questions will be given: why is it necessary to determine the dose of patient in X-ray studies, what is the reference dose level and how it is used for dosimetric quantity which characterized the patient's exposure in X-ray, mammography and CT scans and how they are measured, who conducted the measurement and how to keep the records, what are the variations of doses in identical tests and what defines them? The findings from a national survey of doses in diagnostic radiology, conducted in 2008-2009 and the developed new national reference levels will be presented. The main findings of the first tests of radiological equipment and the future role of quality control as well as the concept of conducting clinical audit and its role in quality assurance are also presented. Quality assurance of the diagnostic process with minimal exposure of patients is a strategic goal whose realization requires understanding, organization and practical action, both nationally and in every hospital. To achieve this the important role of education and training of physicians, radiological technicians and medical physicists is enhanced

Encryption for confidentiality of the network and influence of this to the quality of streaming video through network

Science.gov (United States)

Sevcik, L.; Uhrin, D.; Frnda, J.; Voznak, M.; Toral-Cruz, Homer; Mikulec, M.; Jakovlev, Sergej

2015-05-01

Nowadays, the interest in real-time services, like audio and video, is growing. These services are mostly transmitted over packet networks, which are based on IP protocol. It leads to analyses of these services and their behavior in such networks which are becoming more frequent. Video has become the significant part of all data traffic sent via IP networks. In general, a video service is one-way service (except e.g. video calls) and network delay is not such an important factor as in a voice service. Dominant network factors that influence the final video quality are especially packet loss, delay variation and the capacity of the transmission links. Analysis of video quality concentrates on the resistance of video codecs to packet loss in the network, which causes artefacts in the video. IPsec provides confidentiality in terms of safety, integrity and non-repudiation (using HMAC-SHA1 and 3DES encryption for confidentiality and AES in CBC mode) with an authentication header and ESP (Encapsulating Security Payload). The paper brings a detailed view of the performance of video streaming over an IP-based network. We compared quality of video with packet loss and encryption as well. The measured results demonstrated the relation between the video codec type and bitrate to the final video quality.

Quality Assessment of Adaptive Bitrate Videos using Image Metrics and Machine Learning

DEFF Research Database (Denmark)

Søgaard, Jacob; Forchhammer, Søren; Brunnström, Kjell

2015-01-01

Adaptive bitrate (ABR) streaming is widely used for distribution of videos over the internet. In this work, we investigate how well we can predict the quality of such videos using well-known image metrics, information about the bitrate levels, and a relatively simple machine learning method...

Simultaneous recording of EEG and electromyographic polygraphy increases the diagnostic yield of video-EEG monitoring.

Science.gov (United States)

Hill, Aron T; Briggs, Belinda A; Seneviratne, Udaya

2014-06-01

To investigate the usefulness of adjunctive electromyographic (EMG) polygraphy in the diagnosis of clinical events captured during long-term video-EEG monitoring. A total of 40 patients (21 women, 19 men) aged between 19 and 72 years (mean 43) investigated using video-EEG monitoring were studied. Electromyographic activity was simultaneously recorded with EEG in four patients selected on clinical grounds. In these patients, surface EMG electrodes were placed over muscles suspected to be activated during a typical clinical event. Of the 40 patients investigated, 24 (60%) were given a diagnosis, whereas 16 (40%) remained undiagnosed. All four patients receiving adjunctive EMG polygraphy obtained a diagnosis, with three of these diagnoses being exclusively reliant on the EMG recordings. Specifically, one patient was diagnosed with propriospinal myoclonus, another patient was diagnosed with facio-mandibular myoclonus, and a third patient was found to have bruxism and periodic leg movements of sleep. The information obtained from surface EMG recordings aided the diagnosis of clinical events captured during video-EEG monitoring in 7.5% of the total cohort. This study suggests that EEG-EMG polygraphy may be used as a technique of improving the diagnostic yield of video-EEG monitoring in selected cases.

[The diagnostic significance of nailfold video-capillaroscopy in systemic sclerosis].

Science.gov (United States)

Li, Lin-Guang; Zhang, Jiang-Lin; Liu, Xiu-Hua; Huang, Feng

2012-05-01

To observe nailfold capillary changes in a cohort of connective tissue disease (CTD) with Raynaud's phenomenon (RP) and to explore the diagnostic value of nailfold video-capillaroscopy (NVC) in systemic sclerosis (SSc). Sixty CTD patients with RP divided into SSc group (n = 36) and non-SSc group (n = 24) were referred to an experienced operator for NVC. The patients had decreased capillary loops in SSc group with the capillary diameter more enlarged in SSc group than non-SSc group. The number of patients in SSc group with giant capillaries was 14, while 3 in non-SSc group. There were 23 patients with haemorrhages in SSc group and 9 in non-SSc group. The number of patients with severe effusion was 15 in SSc group, while 2 in non-SSc group. By using the ROC curves, indexes with AUC at least 0.7 of the input capillary diameter, the output capillary diameter, the middle capillary diameter, blood color and effusion for the diagnostic cutoff points were 18.5 µm, 24.5 µm, 19.5µm, deep red and severe effusion. With at least 2 out of the top 3 indexes, the diagnostic sensitivity and specificity of SSc were higher. CTD Patients with RP of SSc have less capillary loops, more enlarged capillaries, more giant capillaries, more severe effusion and more haemorrhages than non-SSc patients. The characteristics of nailfold capillary changes in SSc patients with RP can be helpful for the diagnosis and the differential diagnosis of SSc.

Interactional Quality Depicted in Infant and Toddler Videos: Where Are the Interactions?

Science.gov (United States)

Fenstermacher, Susan K.; Barr, Rachel; Brey, Elizabeth; Pempek, Tiffany A.; Ryan, Maureen; Calvert, Sandra L.; Shwery, Clay E.; Linebarger, Deborah

2010-01-01

This study examined the social-emotional content and the quality of social interactions depicted in a sample of 58 DVDs marketed towards infants and toddlers. Infant-directed videos rarely used social interactions between caregiver and child or between peers to present content. Even when videos explicitly targeted social-emotional content,…

High-quality and small-capacity e-learning video featuring lecturer-superimposing PC screen images

Science.gov (United States)

Nomura, Yoshihiko; Murakami, Michinobu; Sakamoto, Ryota; Sugiura, Tokuhiro; Matsui, Hirokazu; Kato, Norihiko

2006-10-01

Information processing and communication technology are progressing quickly, and are prevailing throughout various technological fields. Therefore, the development of such technology should respond to the needs for improvement of quality in the e-learning education system. The authors propose a new video-image compression processing system that ingeniously employs the features of the lecturing scene. While dynamic lecturing scene is shot by a digital video camera, screen images are electronically stored by a PC screen image capturing software in relatively long period at a practical class. Then, a lecturer and a lecture stick are extracted from the digital video images by pattern recognition techniques, and the extracted images are superimposed on the appropriate PC screen images by off-line processing. Thus, we have succeeded to create a high-quality and small-capacity (HQ/SC) video-on-demand educational content featuring the advantages: the high quality of image sharpness, the small electronic file capacity, and the realistic lecturer motion.

A model linking video gaming, sleep quality, sweet drinks consumption and obesity among children and youth.

Science.gov (United States)

Turel, O; Romashkin, A; Morrison, K M

2017-08-01

There is a growing need to curb paediatric obesity. The aim of this study is to untangle associations between video-game-use attributes and obesity as a first step towards identifying and examining possible interventions. Cross-sectional time-lagged cohort study was employed using parent-child surveys (t1) and objective physical activity and physiological measures (t2) from 125 children/adolescents (mean age = 13.06, 9-17-year-olds) who play video games, recruited from two clinics at a Canadian academic children's hospital. Structural equation modelling and analysis of covariance were employed for inference. The results of the study are as follows: (i) self-reported video-game play duration in the 4-h window before bedtime is related to greater abdominal adiposity (waist-to-height ratio) and this association may be mediated through reduced sleep quality (measured with the Pittsburgh Sleep Quality Index); and (ii) self-reported average video-game session duration is associated with greater abdominal adiposity and this association may be mediated through higher self-reported sweet drinks consumption while playing video games and reduced sleep quality. Video-game play duration in the 4-h window before bedtime, typical video-game session duration, sweet drinks consumption while playing video games and poor sleep quality have aversive associations with abdominal adiposity. Paediatricians and researchers should further explore how these factors can be altered through behavioural or pharmacological interventions as a means to reduce paediatric obesity. © 2017 World Obesity Federation.

A regression method for real-time video quality evaluation

NARCIS (Netherlands)

Torres Vega, M.; Mocanu, D.C.; Liotta, A.; Abdulrazak, B.; Pardede, E.; Steinbauer, M.; Khalil, I.; Anderst-Kotsis, G.

2016-01-01

No-Reference (NR) metrics provide a mechanism to assess video quality in an ever-growing wireless network. Their low computational complexity and functional characteristics make them the primary choice when it comes to realtime content management and mobile streaming control. Unfortunately, common

Video Quality Assessment and Machine Learning: Performance and Interpretability

DEFF Research Database (Denmark)

Søgaard, Jacob; Forchhammer, Søren; Korhonen, Jari

2015-01-01

In this work we compare a simple and a complex Machine Learning (ML) method used for the purpose of Video Quality Assessment (VQA). The simple ML method chosen is the Elastic Net (EN), which is a regularized linear regression model and easier to interpret. The more complex method chosen is Support...... Vector Regression (SVR), which has gained popularity in VQA research. Additionally, we present an ML-based feature selection method. Also, it is investigated how well the methods perform when tested on videos from other datasets. Our results show that content-independent cross-validation performance...... on a single dataset can be misleading and that in the case of very limited training and test data, especially in regards to different content as is the case for many video datasets, a simple ML approach is the better choice....

Video game addiction: The push to pathologize video games

DEFF Research Database (Denmark)

Nielsen, Rune Kristian Lundedal; Ferguson, Christopher; Bean, Anthony

2017-01-01

With proposals to include “gaming disorder” in both the Diagnostic and Statistical Manual (DSM) and International Compendium of Diseases (ICD), the concept of video game addiction has gained traction. However, many aspects of this concept remain controversial. At present, little clarity has been...... achieved regarding diagnostic criteria and appropriate symptoms. It is unclear if symptoms that involve problematic video gaming behavior should be reified as a new disorder, or are the expression of underlying mental conditions. Nonetheless, the recent proposals around gaming disorder from respected...... and necessity of the overarching construct. This raises multiple concerns. First, the current approaches to understanding “gaming addiction” are rooted in substance abuse research and approaches do not necessarily translate to media consumption. Second, some research has indicated that “video game addiction...

Quality control in diagnostic radiology: experience and challenges

International Nuclear Information System (INIS)

Abd Aziz Mhd Ramli; Mohd Ramli Arshad; Mohd Khalid Matori; Muhammad Jamal Md Isa; Husaini Salleh; Abdullah Tahir Aliyasak; Zainal Jamaluddin; Hasrul Hisham Hussain

2005-01-01

Malaysian Institute for Nuclear Technology Research through its Medical Physics Group has been providing Quality Control (QC) services for medical x-ray apparatus used in diagnostic radiology to private clinics and hospitals since the year 1997. The quality control (QC) in diagnostic radiology is considered as part of quality assurance program which provide accurate diagnostic information at the lowest cost and the least exposure of the patients to radiation. Many experience and obstacles were faced by Medical Physics Group. This paper will discuss on some of the experiences and challenges that could be shared together with MINT staff especially in the safety aspect related to electrical and mechanical, radiation protection, performance and standard. The challenging in administrative aspect also will discuss. (Author)

Video Monitoring a Simulation-Based Quality Improvement Program in Bihar, India.

Science.gov (United States)

Dyer, Jessica; Spindler, Hilary; Christmas, Amelia; Shah, Malay Bharat; Morgan, Melissa; Cohen, Susanna R; Sterne, Jason; Mahapatra, Tanmay; Walker, Dilys

2018-04-01

Simulation-based training has become an accepted clinical training andragogy in high-resource settings with its use increasing in low-resource settings. Video recordings of simulated scenarios are commonly used by facilitators. Beyond using the videos during debrief sessions, researchers can also analyze the simulation videos to quantify technical and nontechnical skills during simulated scenarios over time. Little is known about the feasibility and use of large-scale systems to video record and analyze simulation and debriefing data for monitoring and evaluation in low-resource settings. This manuscript describes the process of designing and implementing a large-scale video monitoring system. Mentees and Mentors were consented and all simulations and debriefs conducted at 320 Primary Health Centers (PHCs) were video recorded. The system design, number of video recordings, and inter-rater reliability of the coded videos were assessed. The final dataset included a total of 11,278 videos. Overall, a total of 2,124 simulation videos were coded and 183 (12%) were blindly double-coded. For the double-coded sample, the average inter-rater reliability (IRR) scores were 80% for nontechnical skills, and 94% for clinical technical skills. Among 4,450 long debrief videos received, 216 were selected for coding and all were double-coded. Data quality of simulation videos was found to be very good in terms of recorded instances of "unable to see" and "unable to hear" in Phases 1 and 2. This study demonstrates that video monitoring systems can be effectively implemented at scale in resource limited settings. Further, video monitoring systems can play several vital roles within program implementation, including monitoring and evaluation, provision of actionable feedback to program implementers, and assurance of program fidelity.

Quality of reporting of diagnostic accuracy studies

NARCIS (Netherlands)

Smidt, N.; Rutjes, A.W.; Windt - Mens, van der D.A.W.M.; Ostelo, R.W.J.G.; Reitsma, J.B.; Bouter, L.M.; Vet, de H.C.W.

2005-01-01

PURPOSE: To evaluate quality of reporting in diagnostic accuracy articles published in 2000 in journals with impact factor of at least 4 by using items of Standards for Reporting of Diagnostic Accuracy (STARD) statement published later in 2003. MATERIALS AND METHODS: English-language articles on

On subjective quality assessment of adaptive video streaming via crowdsourcing and laboratory based experiments

DEFF Research Database (Denmark)

Søgaard, Jacob; Shahid, Muhammad; Pokhrel, Jeevan

2017-01-01

Video streaming services are offered over the Internet and since the service providers do not have full control over the network conditions all the way to the end user, streaming technologies have been developed to maintain the quality of service in these varying network conditions i.e. so called...... adaptive video streaming. In order to cater for users' Quality of Experience (QoE) requirements, HTTP based adaptive streaming solutions of video services have become popular. However, the keys to ensure the users a good QoE with this technology is still not completely understood. User QoE feedback...

Capturing and displaying microscopic images used in medical diagnostics and forensic science using 4K video resolution – an application in higher education

NARCIS (Netherlands)

Jan Kuijten; Ajda Ortac; Hans Maier; Gert de Heer

2015-01-01

To analyze, interpret and evaluate microscopic images, used in medical diagnostics and forensic science, video images for educational purposes were made with a very high resolution of 4096 × 2160 pixels (4K), which is four times as many pixels as High-Definition Video (1920 × 1080 pixels).

EDICAM fast video diagnostic installation on the COMPASS tokamak

Czech Academy of Sciences Publication Activity Database

Szappanos, A.; Berta, M.; Hron, Martin; Pánek, Radomír; Stöckel, Jan; Veres, G.; Weinzettl, Vladimír; Zoletnik, S.; Tulipán, S.

2010-01-01

Roč. 85, 3-4 (2010), s. 370-373 ISSN 0920-3796. [IAEA Technical Meeting on Control, Data Acquisition and Remote Participation for Fusion Research/7th./. Aix – en – Provence, 15.06.2009-19.06.2009] Institutional research plan: CEZ:AV0Z20430508 Keywords : Video diagnostic * Fast data processing * CMOS sensor * Image processing Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.143, year: 2010 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V3C-4Y0C2FK-1&_user=6542793&_coverDate=07%2F31%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000070123&_version=1&_urlVersion=0&_userid=6542793&md5=99eb6704be38e61ac7e2316cb63a7ee9&searchtype=a

Total quality management (TQM) in diagnostic radiology

International Nuclear Information System (INIS)

Rehani, M.M.

1995-01-01

The branch of quality assurance is now taking a new direction towards total quality management (TQM). Being of industrial origin, the concepts and terminologies in TQM are alien to medical and paramedical professionals. However, the impetus it has already made in other areas of health sciences makes medical physicists left out when diagnostic radiology does not encompass TQM. The purpose of this paper is to introduce the terms used in TQM and some aspects of its application to diagnostic radiology. (author). 12 refs., 1 tab

Impact of Constant Rate Factor on Objective Video Quality Assessment

Directory of Open Access Journals (Sweden)

Juraj Bienik

2017-01-01

Full Text Available This paper deals with the impact of constant rate factor value on the objective video quality assessment using PSNR and SSIM metrics. Compression efficiency of H.264 and H.265 codecs defined by different Constant rate factor (CRF values was tested. The assessment was done for eight types of video sequences depending on content for High Definition (HD, Full HD (FHD and Ultra HD (UHD resolution. Finally, performance of both mentioned codecs with emphasis on compression ratio and efficiency of coding was compared.

Quality Control in Diagnostic Radiology in the Netherlands (invited paper)

International Nuclear Information System (INIS)

Zoetelief, J.

1998-01-01

Application of the general principles of radiation protection to medical diagnostic radiology implies that each procedure using X rays or radionuclides is to be justified and optimised. Optimisation in diagnostic radiology implies that the radiation burden to the patient should be as low as possible, but compatible with the image quality necessary to obtain an adequate diagnosis or to guide treatment. Quality control of equipment is a prerequisite for achieving optimisation in diagnostic radiology. This was especially recognised for mammography as employed for breast cancer screening. Existing legislation in the Netherlands includes only a few criteria for equipment used in diagnostic radiology. In addition, the criteria are not all operational and measurement methods are lacking. Therefore, upon the initiative of the Dutch Ministry of Health, Welfare and Sports, the relevant professional societies, in collaboration with the former TNO Centre for Radiological Protection and Dosimetry, formulated eleven guidelines for quality control of equipment used in diagnostic radiology, including test procedures, test frequencies and limiting values. The implementation of quality control of equipment was included in the 1984 European Directive (84/466/Euratom) laying down basic measures for the radiation protection of persons undergoing medical examination or treatment. In the most recent European Directive on medical exposure (97/43/Euratom) the importance of quality control is stressed. In addition, the latter EC directive proposes the use of diagnostic reference levels for limiting the risks for patients undergoing diagnostic radiology. In the Netherlands preliminary reference levels for various procedures employed in diagnostic radiology are suggested. Finally, methods applied in the Netherlands for assessment of image quality are discussed. (author)

Quality of pharmaceutical care at the pharmacy counter : Patients’ experiences versus video observation

NARCIS (Netherlands)

Koster, Ellen S.; Blom, Lyda; Overbeeke, Marloes R.; Philbert, Daphne; Vervloet, Marcia; Koopman, Laura; van Dijk, Liset

2016-01-01

Introduction: Consumer Quality Index questionnaires are used to assess quality of care from patients’ experiences. Objective: To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations. Methods: Pharmaceutical

Quality of pharmaceutical care at the pharmacy counter: patients’ experiences versus video observation.

NARCIS (Netherlands)

Koster, E.S.; Blom, L.; Overbeeke, M.R.; Philbert, D.; Vervloet, M.; Koopman, L.; Dijk, L. van

2016-01-01

Introduction: Consumer Quality Index questionnaires are used to assess quality of care from patients’ experiences. Objective: To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations. Methods: Pharmaceutical

Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

International Nuclear Information System (INIS)

Wright, R.; Zander, M.; Brown, S.; Sandoval, D.; Gilpatrick, D.; Gibson, H.

1992-01-01

This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) is discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. (Author) (3 figs., 4 refs.)

Compensating for Type-I Errors in Video Quality Assessment

DEFF Research Database (Denmark)

Brunnström, Kjell; Tavakoli, Samira; Søgaard, Jacob

2015-01-01

This paper analyzes the impact on compensating for Type-I errors in video quality assessment. A Type-I error is to incorrectly conclude that there is an effect. The risk increases with the number of comparisons that are performed in statistical tests. Type-I errors are an issue often neglected...

Predicting personal preferences in subjective video quality assessment

DEFF Research Database (Denmark)

Korhonen, Jari

2017-01-01

In this paper, we study the problem of predicting the visual quality of a specific test sample (e.g. a video clip) experienced by a specific user, based on the ratings by other users for the same sample and the same user for other samples. A simple linear model and algorithm is presented, where...... the characteristics of each test sample are represented by a set of parameters, and the individual preferences are represented by weights for the parameters. According to the validation experiment performed on public visual quality databases annotated with raw individual scores, the proposed model can predict...

[Evaluation of quality of HIV diagnostic procedures in Poland].

Science.gov (United States)

Parczewski, Miłosz; Madaliński, Kazimierz; Leszczyszyn-Pynka, Magdalena; Boroń-Kaczmarska, Anna

2010-01-01

The aim of this work was quality assessment of HIV diagnostic procedures in Poland, including human and technical resources as well as laboratory practice. Sixty questionnaires were distributed among diagnostic centers to obtain qualitative data. Basing on the survey data serological control using coded panels of HIV-1/2 samples was performed. Thirty-one filled questionnaires were received (50.8%). Surveyed laboratories perform from 350 to 5500 serological screening tests per year. In most of laboratories fourth generation assays are available, while Blood Donation Centers screen the blood both with serological assays and by HIV-RNA detection. Sanitary and Epidemiological Stations and academic laboratories hold the ISO/IEC 17025 or IS0 9001:2001 accreditation, five of the surveyed centers participate in Labquality assurance and two in Quality Control in Molecular Diagnostics programs. Data of control serological testing were received from 21 centers. In the quality control assessment 194 analyses were performed with 91 true negative, 2 false negative, 96 true positive and 5 false positive results. False negative rate of % and false positive rate of 5.2% was noted for this study. Currently, virtually no guidelines related to the HIV-diagnostics quality assurance and control in Poland are in delineated. Development of the national unified quality control system, basing on the central institution is highly desirable. National certification within the frames of the quality control and assurance program should be mandatory for all the diagnostic labs, and aim at improvement of reliability of the result distributed among clinicians and patients.

Image quality - physical and diagnostic parameters. The radiologist's viewpoint

International Nuclear Information System (INIS)

Stender, H.St.

1985-01-01

The quality of a radiograph is determined by the diagnostic information it provides. This depends upon the visual detection of diagnostically relevant structures. The technical radiographic requirements are dependent upon the physical measurements and the physiological and optical conditions. Such physical factors as spatial resolution, contrast and noise are quantitative measurements, which must be oriented to the qualitative visual characteristics of the radiograph. The influence of subjective perception and complexity of structural noise on the detectability of details and structures particularly demands attention. Since radiographic quality depends upon the detection of diagnostically relevant structure and features, it is important to define these parameters on the basis of extensive radiographic analysis and the corresponding clinical findings. The diagnostically relevant radiographic parameters and image details and critical structures have been worked out for the examination of the lungs, colon, stomach, urinary tract and skeleton. Good image quality requires coordination of the physical-technical parameters with the visual ability of the observer, since only in this way can the diagnostic information be represented with sufficient clarity. (author)

Quality control for diagnostic oral microbiology laboratories in European countries

NARCIS (Netherlands)

Rautemaa-Richardson, R.; van der Reijden, W.A.; Dahlen, G.; Smith, A.J.

2011-01-01

Participation in diagnostic microbiology internal and external quality control (QC) processes is good laboratory practice and an essential component of a quality management system. However, no QC scheme for diagnostic oral microbiology existed until 2009 when the Clinical Oral Microbiology (COMB)

Quality Control in Diagnostic Radiology: Experiences and Achievements

International Nuclear Information System (INIS)

Mohd Khalid Matori; Husaini Salleh; Muhammad Jamal Md Isa

2015-01-01

Malaysian Nuclear Agency through its Medical Physics Group has been providing Quality Control (QC) services for medical X-ray apparatus used in diagnostic radiology to private clinics and hospitals since the year 1997. The Medical Physics Groups services is endorsed by the Malaysian Ministry Of Health (MOH) and is in accordance with the Malaysian Standard MS 838 and the Atomic Energy Licensing Act, 1984. Until today, the scopes of testing services also include all types of medical x-ray apparatus. The quality control (QC) in diagnostic radiology is considered as part of quality assurance program which provide accurate diagnostic information at the lowest cost and the least exposure of the patients to radiation. Many experience and obstacles were faced by Medical Physics Group. This paper will discuss the experiences and achievements of providing QC service from early stage until now so that it can be shared by the citizens of the Malaysian Nuclear Agency. The results of quality assurance inspection of all types of X-ray apparatus for medical conducted by Agency Nuclear Malaysia will be presented in brief. (author)

Educational Colonoscopy Video Enhances Bowel Preparation Quality and Comprehension in an Inner City Population.

Science.gov (United States)

Pillai, Ajish; Menon, Radha; Oustecky, David; Ahmad, Asyia

2017-07-24

Quality of bowel preparation and patient knowledge remains a major barrier for completing colorectal cancer screening. Few studies have tested unique ways to impact patient understanding centering on interactive computer programs, pictures, and brochures. Two studies explored instructional videos but focused on patient compliance and anxiety as endpoints. Furthermore, excessive video length and content may limit their impact on a broad patient population. No study so far has studied a video's impact on preparation quality and patient understanding of the colonoscopy procedure. We conducted a single blinded prospective study of inner city patients presenting for a first time screening colonoscopy. During their initial visit patients were randomized to watch an instructional colonoscopy video or a video discussing gastroesophageal reflux disease (GERD). All patients watched a 6 minutes long video with the same spokesperson, completed a demographic questionnaire (Supplemental Digital Content 1, http://links.lww.com/JCG/A352) and were enrolled only if screened within 30 days of their visit. On the day of the colonoscopy, patients completed a 14 question quiz of their knowledge. Blinded endoscopist graded patient preparations based on the Ottawa scale. All authors had access to the study data and reviewed and approved the final manuscript. Among the 104 subjects enrolled in the study, 56 were in the colonoscopy video group, 48 were in GERD video group, and 12 were excluded. Overall, 48% were male and 52% female; 90% of patients had less than a high school education, 76% were African American, and 67% used a 4 L split-dose preparation. There were no differences between either video group with regard to any of the above categories. Comparisons between the 2 groups revealed that the colonoscopy video group had significantly better Ottawa bowel preparation score (4.77 vs. 6.85; P=0.01) than the GERD video group. The colonoscopy video group also had less-inadequate repeat

Problems of quality assurance and quality control in diagnostic radiology

International Nuclear Information System (INIS)

Angerstein, W.

1986-01-01

Topical problems of quality assurance and quality control in diagnostic radiology are discussed and possible solutions are shown. Complex units are differentiated with reference to physicians, technicians, organization of labour, methods of examination and indication. Quality control of radiologic imaging systems should involve three stages: (1) simple tests carried out by radiologic technicians, (2) measurements by service technicians, (3) testing of products by the manufacturer and independent governmental or health service test agencies. (author)

Quality systems in veterinary diagnostics laboratories.

Science.gov (United States)

de Branco, Freitas Maia L M

2007-01-01

Quality assurance of services provided by veterinary diagnostics laboratories is a fundamental element promoted by international animal health organizations to establish trust, confidence and transparency needed for the trade of animals and their products at domestic and international levels. It requires, among other things, trained personnel, consistent and rigorous methodology, choice of suitable methods as well as appropriate calibration and traceability procedures. An important part of laboratory quality management is addressed by ISO/IEC 17025, which aims to facilitate cooperation among laboratories and their associated parties by assuring the generation of credible and consistent information derived from analytical results. Currently, according to OIE recommendation, veterinary diagnostics laboratories are only subject to voluntary compliance with standard ISO/IEC 17025; however, it is proposed here that OIE reference laboratories and collaboration centres strongly consider its adoption.

Basic quality control in diagnostic radiology

International Nuclear Information System (INIS)

Wikstrom, Erik

2016-01-01

Along the route toward regular performance of Quality Control in the Diagnostic Imaging sector there are a number of balances to negotiate: Patient/Staff safety considerations vs Regulatory compliance vs Performance of modern equipment vs Clinic's Productivity. At first glance these ambitions may seem in conflict. The tests performed to meet regulatory requirements may or may not bear any semblance to real clinical measurement scenarios. And the process of collecting the data from the quality assurance tests may induce a system down- time that adversely affects the clinic's overall productivity. Furthermore, the time it takes to complete the analysis of the test data and provide the report required to take the facility back into operation is time wasted for patients waiting for a diagnostic imaging exam

Radiological protection and quality control for diagnostic radiology in China

International Nuclear Information System (INIS)

Baorong, Yue

2008-01-01

Full text: There are 43,000 diagnostic departments, nearly 70,000 X-ray diagnostic facilities, 7,000 CT, 250 million for the annual total numbers of X-ray examinations, 120,000 occupationally exposed workers in diagnostic radiology. 'Basic standards for protection against ionizing radiation and for the safety of radiation sources' is promulgated on October, 2002. This basic standard follows the BSS. 'Rule on the administration of radio-diagnosis and radiotherapy', as a order of the Ministry of Health No. 46, is promulgated by Minister of Health on January 24, 2006. It includes general provisions, requirements and practice, establishment and approval of radio-diagnosis and radiotherapy services, safeguards and quality assurance, and so on. There are a series of radiological protection standards and quality control standards in diagnostic radiology, including 'radiological protection standard for the examination in X-ray diagnosis', 'radiological health protection standards for X-ray examination of child-bearing age women and pregnant women', 'radiological protection standards for the children in X-ray diagnosis', 'standards for radiological protection in medical X-ray diagnosis', 'specification for radiological protection monitoring in medical X-ray diagnosis', 'guide for reasonable application of medical X-ray diagnosis', 'general aspects for quality assurance in medical X-ray image of diagnosis', 'specification of image quality control test for the medical X-ray diagnostic equipment', 'specification of image quality assurance test for X-ray equipment for computed tomography', 'specification for testing of quality control in computed radiography (CR)' and 'specification for testing of quality control in X-ray mammography'. With the X-ray diagnostic equipment, there are acceptant tests, status tests and routing tests in large hospitals. It is poor for routing test in middle and smaller hospitals. CT is used widely in diagnostic radiology, however most workers in CT

Quality of pharmaceutical care at the pharmacy counter: patients' experiences versus video observation.

Science.gov (United States)

Koster, Ellen S; Blom, Lyda; Overbeeke, Marloes R; Philbert, Daphne; Vervloet, Marcia; Koopman, Laura; van Dijk, Liset

2016-01-01

Consumer Quality Index questionnaires are used to assess quality of care from patients' experiences. To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations. Pharmaceutical encounters in four pharmacies were video-recorded. Patients completed a questionnaire based upon the Consumer Quality Index Pharmaceutical Care after the encounter containing questions about patients' experiences regarding information provision, medication counseling, and pharmacy staff's communication style. An observation protocol was used to code the recorded encounters. Agreement between video observation and patients' experiences was calculated. In total, 109 encounters were included for analysis. For the domains "medication counseling" and "communication style", agreement between patients' experiences and observations was very high (>90%). Less agreement (45%) was found for "information provision", which was rated more positive by patients compared to the observations, especially for the topic, encouragement of patients' questioning behavior. A questionnaire is useful to assess the quality of medication counseling and pharmacy staff's communication style, but might be less suitable to evaluate information provision and pharmacy staff's encouragement of patients' questioning behavior. Although patients may believe that they have received all necessary information to use their new medicine, some information on specific instructions was not addressed during the encounter. When using questionnaires to get insight into information provision, observations of encounters are very informative to validate the patient questionnaires and make necessary adjustments.

Image quality enhancement for skin cancer optical diagnostics

Science.gov (United States)

Bliznuks, Dmitrijs; Kuzmina, Ilona; Bolocko, Katrina; Lihachev, Alexey

2017-12-01

The research presents image quality analysis and enhancement proposals in biophotonic area. The sources of image problems are reviewed and analyzed. The problems with most impact in biophotonic area are analyzed in terms of specific biophotonic task - skin cancer diagnostics. The results point out that main problem for skin cancer analysis is the skin illumination problems. Since it is often not possible to prevent illumination problems, the paper proposes image post processing algorithm - low frequency filtering. Practical results show diagnostic results improvement after using proposed filter. Along that, filter do not reduces diagnostic results' quality for images without illumination defects. Current filtering algorithm requires empirical tuning of filter parameters. Further work needed to test the algorithm in other biophotonic applications and propose automatic filter parameter selection.

High-resolution, low-delay, and error-resilient medical ultrasound video communication using H.264/AVC over mobile WiMAX networks.

Science.gov (United States)

Panayides, Andreas; Antoniou, Zinonas C; Mylonas, Yiannos; Pattichis, Marios S; Pitsillides, Andreas; Pattichis, Constantinos S

2013-05-01

In this study, we describe an effective video communication framework for the wireless transmission of H.264/AVC medical ultrasound video over mobile WiMAX networks. Medical ultrasound video is encoded using diagnostically-driven, error resilient encoding, where quantization levels are varied as a function of the diagnostic significance of each image region. We demonstrate how our proposed system allows for the transmission of high-resolution clinical video that is encoded at the clinical acquisition resolution and can then be decoded with low-delay. To validate performance, we perform OPNET simulations of mobile WiMAX Medium Access Control (MAC) and Physical (PHY) layers characteristics that include service prioritization classes, different modulation and coding schemes, fading channels conditions, and mobility. We encode the medical ultrasound videos at the 4CIF (704 × 576) resolution that can accommodate clinical acquisition that is typically performed at lower resolutions. Video quality assessment is based on both clinical (subjective) and objective evaluations.

Video Classification and Adaptive QoP/QoS Control for Multiresolution Video Applications on IPTV

Directory of Open Access Journals (Sweden)

Huang Shyh-Fang

2012-01-01

Full Text Available With the development of heterogeneous networks and video coding standards, multiresolution video applications over networks become important. It is critical to ensure the service quality of the network for time-sensitive video services. Worldwide Interoperability for Microwave Access (WIMAX is a good candidate for delivering video signals because through WIMAX the delivery quality based on the quality-of-service (QoS setting can be guaranteed. The selection of suitable QoS parameters is, however, not trivial for service users. Instead, what a video service user really concerns with is the video quality of presentation (QoP which includes the video resolution, the fidelity, and the frame rate. In this paper, we present a quality control mechanism in multiresolution video coding structures over WIMAX networks and also investigate the relationship between QoP and QoS in end-to-end connections. Consequently, the video presentation quality can be simply mapped to the network requirements by a mapping table, and then the end-to-end QoS is achieved. We performed experiments with multiresolution MPEG coding over WIMAX networks. In addition to the QoP parameters, the video characteristics, such as, the picture activity and the video mobility, also affect the QoS significantly.

Quality of pharmaceutical care at the pharmacy counter: patients’ experiences versus video observation

Directory of Open Access Journals (Sweden)

Koster ES

2016-03-01

Full Text Available Ellen S Koster,1 Lyda Blom,1 Marloes R Overbeeke,1 Daphne Philbert,1 Marcia Vervloet,2 Laura Koopman,2,3 Liset van Dijk2 1Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, the Netherlands; 2Netherlands Institute of Health Services Research (NIVEL, Utrecht, the Netherlands; 3National Health Care Institute, Diemen, the Netherlands Introduction: Consumer Quality Index questionnaires are used to assess quality of care from patients’ experiences.Objective: To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations.Methods: Pharmaceutical encounters in four pharmacies were video-recorded. Patients completed a questionnaire based upon the Consumer Quality Index Pharmaceutical Care after the encounter containing questions about patients’ experiences regarding information provision, medication counseling, and pharmacy staff’s communication style. An observation protocol was used to code the recorded encounters. Agreement between video observation and patients’ experiences was calculated.Results: In total, 109 encounters were included for analysis. For the domains “medication counseling” and “communication style”, agreement between patients’ experiences and observations was very high (>90%. Less agreement (45% was found for “information provision”, which was rated more positive by patients compared to the observations, especially for the topic, encouragement of patients’ questioning behavior.Conclusion: A questionnaire is useful to assess the quality of medication counseling and pharmacy staff’s communication style, but might be less suitable to evaluate information provision and pharmacy staff’s encouragement of patients’ questioning behavior. Although patients may believe that they have received all necessary information to use their new medicine, some information on specific instructions was not addressed during

Degraded visual environment image/video quality metrics

Science.gov (United States)

Baumgartner, Dustin D.; Brown, Jeremy B.; Jacobs, Eddie L.; Schachter, Bruce J.

2014-06-01

A number of image quality metrics (IQMs) and video quality metrics (VQMs) have been proposed in the literature for evaluating techniques and systems for mitigating degraded visual environments. Some require both pristine and corrupted imagery. Others require patterned target boards in the scene. None of these metrics relates well to the task of landing a helicopter in conditions such as a brownout dust cloud. We have developed and used a variety of IQMs and VQMs related to the pilot's ability to detect hazards in the scene and to maintain situational awareness. Some of these metrics can be made agnostic to sensor type. Not only are the metrics suitable for evaluating algorithm and sensor variation, they are also suitable for choosing the most cost effective solution to improve operating conditions in degraded visual environments.

The european approach to quality assurance in diagnostic radiology

International Nuclear Information System (INIS)

Benini, A.

1997-01-01

The european and increasingly the international organizations are emphasizing the importance of appropriate quality assurance programmes in diagnostic radiology. The European Directive (particularly the directive 84/466/EURATOM). the various publications of the International Commission for radiation protection (ICRP), related to protection of the patients and workers and the Basic Safety Standards of the International Atomic Energy Agency (IAEA) might be considered the landmarks of the new approach to the problems of dose reduction and quality in diagnostic radiology. In particular ICRP maintains a watching brief on all aspects related to radiation protection and makes recommendations concerning basic principles. Since ICRP 26 (1977), several ICRP publications have dealt with all the principal fields of diagnostic radiology. The IAEA has recently published the new Basic Safety Standards including guidance levels for the most common diagnostic investigations.Within the European countries the European Union and the European legislation have strong influence of the implementation of radiation protection and Q A at a national level. This has led to a substantial effort in the european countries to establish national standards and basic quality requirements. (author)

The Quality of Open-Access Video-Based Orthopaedic Instructional Content for the Shoulder Physical Exam is Inconsistent.

Science.gov (United States)

Urch, Ekaterina; Taylor, Samuel A; Cody, Elizabeth; Fabricant, Peter D; Burket, Jayme C; O'Brien, Stephen J; Dines, David M; Dines, Joshua S

2016-10-01

The internet has an increasing role in both patient and physician education. While several recent studies critically appraised the quality and accuracy of web-based written information available to patients, no studies have evaluated such parameters for open-access video content designed for provider use. The primary goal of the study was to determine the accuracy of internet-based instructional videos featuring the shoulder physical examination. An assessment of quality and accuracy of said video content was performed using the basic shoulder examination as a surrogate for the "best-case scenario" due to its widely accepted components that are stable over time. Three search terms ("shoulder," "examination," and "shoulder exam") were entered into the four online video resources most commonly accessed by orthopaedic surgery residents (VuMedi, G9MD, Orthobullets, and YouTube). Videos were captured and independently reviewed by three orthopaedic surgeons. Quality and accuracy were assessed in accordance with previously published standards. Of the 39 video tutorials reviewed, 61% were rated as fair or poor. Specific maneuvers such as the Hawkins test, O'Brien sign, and Neer impingement test were accurately demonstrated in 50, 36, and 27% of videos, respectively. Inter-rater reliability was excellent (mean kappa 0.80, range 0.79-0.81). Our results suggest that information presented in open-access video tutorials featuring the physical examination of the shoulder is inconsistent. Trainee exposure to such potentially inaccurate information may have a significant impact on trainee education.

Educational Quality of YouTube Videos in Thumb Exercises for Carpometacarpal Osteoarthritis: A Search on Current Practice.

Science.gov (United States)

Villafañe, Jorge Hugo; Cantero-Tellez, Raquel; Valdes, Kristin; Usuelli, Federico Giuseppe; Berjano, Pedro

2017-09-01

Conservative treatments are commonly performed therapeutic interventions for the management of carpometacarpal (CMC) joint osteoarthritis (OA). Physical and occupational therapies are starting to use video-based online content as both a patient teaching tool and a source for treatment techniques. YouTube is a popular video-sharing website that can be accessed easily. The purpose of this study was to analyze the quality of content and potential sources of bias in videos available on YouTube pertaining to thumb exercises for CMC OA. The YouTube video database was systematically searched using the search term thumb osteoarthritis and exercises from its inception to March 10, 2017. Authors independently selected videos, conducted quality assessment, and extracted results. A total of 832 videos were found using the keywords. Of these, 10 videos clearly demonstrated therapeutic exercise for the management of CMC OA. In addition, the top-ranked video found by performing a search of "views" was a video with more than 121 863 views uploaded in 2015 that lasted 12.33 minutes and scored only 2 points on the Global Score for Educational Value rating scale. Most of the videos viewed that described conservative interventions for CMC OA management have a low level of evidence to support their use. Although patients and novice hand therapists are using YouTube and other online resources, videos that are produced by expert hand therapists are scarce.

Quality of pharmaceutical care at the pharmacy counter: patients’ experiences versus video observation

Science.gov (United States)

Koster, Ellen S; Blom, Lyda; Overbeeke, Marloes R; Philbert, Daphne; Vervloet, Marcia; Koopman, Laura; van Dijk, Liset

2016-01-01

Introduction Consumer Quality Index questionnaires are used to assess quality of care from patients’ experiences. Objective To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations. Methods Pharmaceutical encounters in four pharmacies were video-recorded. Patients completed a questionnaire based upon the Consumer Quality Index Pharmaceutical Care after the encounter containing questions about patients’ experiences regarding information provision, medication counseling, and pharmacy staff’s communication style. An observation protocol was used to code the recorded encounters. Agreement between video observation and patients’ experiences was calculated. Results In total, 109 encounters were included for analysis. For the domains “medication counseling” and “communication style”, agreement between patients’ experiences and observations was very high (>90%). Less agreement (45%) was found for “information provision”, which was rated more positive by patients compared to the observations, especially for the topic, encouragement of patients’ questioning behavior. Conclusion A questionnaire is useful to assess the quality of medication counseling and pharmacy staff’s communication style, but might be less suitable to evaluate information provision and pharmacy staff’s encouragement of patients’ questioning behavior. Although patients may believe that they have received all necessary information to use their new medicine, some information on specific instructions was not addressed during the encounter. When using questionnaires to get insight into information provision, observations of encounters are very informative to validate the patient questionnaires and make necessary adjustments. PMID:27042025

Video quality-of-service for consumer terminals : a novel system for programmable components

NARCIS (Netherlands)

Hentschel, C.; Bril, R.J.; Chen, Y.; Braspenning, R.A.C.; Lan, T-H.

2003-01-01

Future consumer terminals will be more and more based on programmable platforms instead of only dedicated hardware. Novel scalable video algorithm (SVA) software modules trade off resource usage against quality of the output signal. SVAs together with a strategy manager and a quality-of-service

VQone MATLAB toolbox: A graphical experiment builder for image and video quality evaluations: VQone MATLAB toolbox.

Science.gov (United States)

Nuutinen, Mikko; Virtanen, Toni; Rummukainen, Olli; Häkkinen, Jukka

2016-03-01

This article presents VQone, a graphical experiment builder, written as a MATLAB toolbox, developed for image and video quality ratings. VQone contains the main elements needed for the subjective image and video quality rating process. This includes building and conducting experiments and data analysis. All functions can be controlled through graphical user interfaces. The experiment builder includes many standardized image and video quality rating methods. Moreover, it enables the creation of new methods or modified versions from standard methods. VQone is distributed free of charge under the terms of the GNU general public license and allows code modifications to be made so that the program's functions can be adjusted according to a user's requirements. VQone is available for download from the project page (http://www.helsinki.fi/psychology/groups/visualcognition/).

APPLICABILITY ANALYSIS OF THE PHASE CORRELATION ALGORITHM FOR STABILIZATION OF VIDEO FRAMES SEQUENCES FOR CAPILLARY BLOOD FLOW

Directory of Open Access Journals (Sweden)

K. A. Karimov

2016-05-01

Full Text Available Videocapillaroscopy is a convenient and non-invasive method of blood flow parameters recovery in the capillaries. Capillaries position can vary at recorded video sequences due to the registration features of capillary blood flow. Stabilization algorithm of video capillary blood flow based on phase correlation is proposed and researched. This algorithm is compared to the known algorithms of video frames stabilization with full-frame superposition and with key points. Programs, based on discussed algorithms, are compared under processing the experimentally recorded video sequences of human capillaries and under processing of computer-simulated sequences of video frames with the specified offset. The full-frame superposition algorithm provides high quality of stabilization; however, the program based on this algorithm requires significant computational resources. Software implementation of the algorithm based on the detection of the key points is characterized by good performance, but provides low quality of stabilization for video sequences capillary blood flow. Algorithm based on phase correlation method provides high quality of stabilization and program realization of this algorithm requires minimal computational resources. It is shown that the phase correlation algorithm is the most useful for stabilization of video sequences for capillaries blood flow. Obtained findings can be used in the software for biomedical diagnostics.

Video Measurements: Quantity or Quality

Science.gov (United States)

Zajkov, Oliver; Mitrevski, Boce

2012-01-01

Students have problems with understanding, using and interpreting graphs. In order to improve the students' skills for working with graphs, we propose Manual Video Measurement (MVM). In this paper, the MVM method is explained and its accuracy is tested. The comparison with the standardized video data software shows that its accuracy is comparable…

Intelligent Packet Shaper to Avoid Network Congestion for Improved Streaming Video Quality at Clients

DEFF Research Database (Denmark)

Kaul, Manohar; Khosla, Rajiv; Mitsukura, Y

2003-01-01

of this intelligent traffic-shaping algorithm on the underlying network real time packet traffic and the eradication of unwanted abruption in the streaming video qualiy. This paper concluded from the end results of the simulation that neural networks are a very superior means of modeling real-time traffic......This paper proposes a traffic shaping algorithm based on neural networks, which adapts to a network over which streaming video is being transmitted. The purpose of this intelligent shaper is to eradicate all traffic congestion and improve the end-user's video quality. It possesses the capability...

Quality criteria in diagnostic radiology of the skeleton

International Nuclear Information System (INIS)

Freyschmidt, J.

1985-01-01

Conventional diagnostic radiology continues to represent the basic technique in skeleton diagnostics and results in decisive diagnoses in more than 80% of all cases. Compared with other examination methods, it is cheap and relatively easy to perform; however, it makes high demands on the physician's clinical and technical expertise. Compared with computerized tomography, conventional radiography has the advantage of decades of experience and of being cheaper by far. The author thinks the following quality criteria to be important in diagnostic radiology of the skeleton: roentgenological examination of one or several skeleton regions in keeping with the clinical issue concerned, accurate visualization of the object in a typical and reproducible projection, radiation quality matched to the dimension of the object, matched mean optical density, visualization of soft tissue near to bones and joints, and radiation dose in keeping with the clinical issue concerned. (orig./MG) [de

Transbronchial Lung Cryobiopsy and Video-assisted Thoracoscopic Lung Biopsy in the Diagnosis of Diffuse Parenchymal Lung Disease. A Meta-analysis of Diagnostic Test Accuracy.

Science.gov (United States)

Iftikhar, Imran H; Alghothani, Lana; Sardi, Alejandro; Berkowitz, David; Musani, Ali I

2017-07-01

Transbronchial lung cryobiopsy is increasingly being used for the assessment of diffuse parenchymal lung diseases. Several studies have shown larger biopsy samples and higher yields compared with conventional transbronchial biopsies. However, the higher risk of bleeding and other complications has raised concerns for widespread use of this modality. To study the diagnostic accuracy and safety profile of transbronchial lung cryobiopsy and compare with video-assisted thoracoscopic surgery (VATS) by reviewing available evidence from the literature. Medline and PubMed were searched from inception until December 2016. Data on diagnostic performance were abstracted by constructing two-by-two contingency tables for each study. Data on a priori selected safety outcomes were collected. Risk of bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies tool. Random effects meta-analyses were performed to obtain summary estimates of the diagnostic accuracy. The pooled diagnostic yield, pooled sensitivity, and pooled specificity of transbronchial lung cryobiopsy were 83.7% (76.9-88.8%), 87% (85-89%), and 57% (40-73%), respectively. The pooled diagnostic yield, pooled sensitivity, and pooled specificity of VATS were 92.7% (87.6-95.8%), 91.0% (89-92%), and 58% (31-81%), respectively. The incidence of grade 2 (moderate to severe) endobronchial bleeding after transbronchial lung cryobiopsy and of post-procedural pneumothorax was 4.9% (2.2-10.7%) and 9.5% (5.9-14.9%), respectively. Although the diagnostic test accuracy measures of transbronchial lung cryobiopsy lag behind those of VATS, with an acceptable safety profile and potential cost savings, the former could be considered as an alternative in the evaluation of patients with diffuse parenchymal lung diseases.

A blinded assessment of video quality in wearable technology for telementoring in open surgery: the Google Glass experience.

Science.gov (United States)

Hashimoto, Daniel A; Phitayakorn, Roy; Fernandez-del Castillo, Carlos; Meireles, Ozanan

2016-01-01

The goal of telementoring is to recreate face-to-face encounters with a digital presence. Open-surgery telementoring is limited by lack of surgeon's point-of-view cameras. Google Glass is a wearable computer that looks like a pair of glasses but is equipped with wireless connectivity, a camera, and viewing screen for video conferencing. This study aimed to assess the safety of using Google Glass by assessing the video quality of a telementoring session. Thirty-four (n = 34) surgeons at a single institution were surveyed and blindly compared via video captured with Google Glass versus an Apple iPhone 5 during the open cholecystectomy portion of a Whipple. Surgeons were asked to evaluate the quality of the video and its adequacy for safe use in telementoring. Thirty-four of 107 invited surgical attendings (32%) responded to the anonymous survey. A total of 50% rated the Google Glass video as fair with the other 50% rating it as bad to poor. A total of 52.9% of respondents rated the Apple iPhone video as good. A significantly greater proportion of respondents felt Google Glass video quality was inadequate for telementoring versus the Apple iPhone's (82.4 vs 26.5%, p safe telementoring. As the device is still in initial phases of development, future iterations or competitor devices may provide a better telementoring application for wearable devices.

Quality of dementia diagnostic evaluation for ethnic minority patients: a nationwide study

DEFF Research Database (Denmark)

Nielsen, T Rune; Andersen, Birgitte Bo; Kastrup, Marianne

2011-01-01

Background/Aims: Diagnostic evaluation of dementia for ethnic minority patients may be challenging. This study aimed to evaluate the quality of diagnostic evaluation of dementia for patients from ethnic minorities in Denmark. Methods: The Danish national hospital registers were used to identify p......: There are significant ethnic disparities in the quality of diagnostic evaluations and outcome of dementia in the secondary healthcare sector....

Traffic and Quality Characterization of the H.264/AVC Scalable Video Coding Extension

Directory of Open Access Journals (Sweden)

Geert Van der Auwera

2008-01-01

Full Text Available The recent scalable video coding (SVC extension to the H.264/AVC video coding standard has unprecedented compression efficiency while supporting a wide range of scalability modes, including temporal, spatial, and quality (SNR scalability, as well as combined spatiotemporal SNR scalability. The traffic characteristics, especially the bit rate variabilities, of the individual layer streams critically affect their network transport. We study the SVC traffic statistics, including the bit rate distortion and bit rate variability distortion, with long CIF resolution video sequences and compare them with the corresponding MPEG-4 Part 2 traffic statistics. We consider (i temporal scalability with three temporal layers, (ii spatial scalability with a QCIF base layer and a CIF enhancement layer, as well as (iii quality scalability modes FGS and MGS. We find that the significant improvement in RD efficiency of SVC is accompanied by substantially higher traffic variabilities as compared to the equivalent MPEG-4 Part 2 streams. We find that separately analyzing the traffic of temporal-scalability only encodings gives reasonable estimates of the traffic statistics of the temporal layers embedded in combined spatiotemporal encodings and in the base layer of combined FGS-temporal encodings. Overall, we find that SVC achieves significantly higher compression ratios than MPEG-4 Part 2, but produces unprecedented levels of traffic variability, thus presenting new challenges for the network transport of scalable video.

Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity

International Nuclear Information System (INIS)

Schueler, Sabine; Walther, Stefan; Schuetz, Georg M.; Schlattmann, Peter; Dewey, Marc

2013-01-01

To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool. Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy. The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item (''Uninterpretable Results'') showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with ''no fulfilment'' increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy. The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies. (orig.)

Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity

Energy Technology Data Exchange (ETDEWEB)

Schueler, Sabine; Walther, Stefan; Schuetz, Georg M. [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Charite Medical School, Department of Radiology, Berlin (Germany); Schlattmann, Peter [University Hospital of Friedrich Schiller University Jena, Department of Medical Statistics, Informatics, and Documentation, Jena (Germany); Dewey, Marc [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Charite Medical School, Department of Radiology, Berlin (Germany); Charite, Institut fuer Radiologie, Berlin (Germany)

2013-06-15

To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool. Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy. The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item (''Uninterpretable Results'') showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with ''no fulfilment'' increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy. The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies. (orig.)

Comprehensive Clinical Audits of Diagnostic Radiology Practices: A Tool for Quality Improvement. Quality Assurance Audit for Diagnostic Radiology Improvement and Learning (QUAADRIL)

International Nuclear Information System (INIS)

2011-01-01

Interest in quality assurance processes and quality improvement in diagnostic radiology is being driven by a number of factors. These include the high cost and complexity of radiological equipment, acknowledgement of the possibility of increasing doses to patients, and the importance of radiological diagnosis to patient management within the health care environment. To acknowledge these interests, clinical audits have been introduced and, in Europe, mandated under a European Directive (Council Directive 97/47/EURATOM). Comprehensive clinical audits focus on clinical management and infrastructure, patient related and technical procedures, and education and research. This publication includes a structured set of standards appropriate for diagnostic radiology, an audit guide to their clinical review, and data collection sheets for the rapid production of reports in audit situations. It will be a useful guide for diagnostic radiology facilities wishing to improve their service to patients through timely diagnosis with minimal radiation dose.

Comprehensive Clinical Audits of Diagnostic Radiology Practices: A Tool for Quality Improvement. Quality Assurance Audit for Diagnostic Radiology Improvement and Learning (QUAADRIL)

International Nuclear Information System (INIS)

2010-01-01

Interest in quality assurance processes and quality improvement in diagnostic radiology is being driven by a number of factors. These include the high cost and complexity of radiological equipment, acknowledgement of the possibility of increasing doses to patients, and the importance of radiological diagnosis to patient management within the health care environment. To acknowledge these interests, clinical audits have been introduced and, in Europe, mandated under a European Directive (Council Directive 97/47/EURATOM). Comprehensive clinical audits focus on clinical management and infrastructure, patient related and technical procedures, and education and research. This publication includes a structured set of standards appropriate for diagnostic radiology, an audit guide to their clinical review, and data collection sheets for the rapid production of reports in audit situations. It will be a useful guide for diagnostic radiology facilities wishing to improve their service to patients through timely diagnosis with minimal radiation dose.

Imagining life with an ostomy: Does a video intervention improve quality-of-life predictions for a medical condition that may elicit disgust?☆

Science.gov (United States)

Angott, Andrea M.; Comerford, David A.; Ubel, Peter A.

2014-01-01

Objective To test a video intervention as a way to improve predictions of mood and quality-of-life with an emotionally evocative medical condition. Such predictions are typically inaccurate, which can be consequential for decision making. Method In Part 1, people presently or formerly living with ostomies predicted how watching a video depicting a person changing his ostomy pouch would affect mood and quality-of-life forecasts for life with an ostomy. In Part 2, participants from the general public read a description about life with an ostomy; half also watched a video depicting a person changing his ostomy pouch. Participants’ quality-of-life and mood forecasts for life with an ostomy were assessed. Results Contrary to our expectations, and the expectations of people presently or formerly living with ostomies, the video did not reduce mood or quality-of-life estimates, even among participants high in trait disgust sensitivity. Among low-disgust participants, watching the video increased quality-of-life predictions for ostomy. Conclusion Video interventions may improve mood and quality-of-life forecasts for medical conditions, including those that may elicit disgust, such as ostomy. Practice implications Video interventions focusing on patients’ experience of illness continue to show promise as components of decision aids, even for emotionally charged health states such as ostomy. PMID:23177398

Quality Assurance Programme for Computed Tomography: Diagnostic and Therapy Applications

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-08-15

This publication presents a harmonized approach to quality assurance in the field of computed tomography applied to both diagnostics and therapy. It gives a careful analysis of the principles and specific instructions that can be used for a quality assurance programme for optimal performance and reduced patient dose in diagnostic radiology. In some cases, radiotherapy programmes are making a transition from 2-D to 3-D radiotherapy, a complex process which critically depends on accurate treatment planning. In this respect, the authors also provide detailed information about the elements needed for quality assurance testing, including those relating to accurate patient characterization as needed for radiotherapy treatment planning.

Constancy check of beam quality in conventional diagnostic X-ray equipment

International Nuclear Information System (INIS)

Costa, Alessandro M.; Badin, Romulo S.; Leite, Marina S.; Caldas, Linda V.E.

2008-01-01

A tandem ionization chamber was developed for quality control programs of X-ray equipment used in conventional radiography and mammography. A methodology for the use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities was established. The application at a medical X-ray imaging facility of this established methodology is presented. The use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities is a useful method to control the performance of the X-ray equipment

Multi-frame super-resolution with quality self-assessment for retinal fundus videos.

Science.gov (United States)

Köhler, Thomas; Brost, Alexander; Mogalle, Katja; Zhang, Qianyi; Köhler, Christiane; Michelson, Georg; Hornegger, Joachim; Tornow, Ralf P

2014-01-01

This paper proposes a novel super-resolution framework to reconstruct high-resolution fundus images from multiple low-resolution video frames in retinal fundus imaging. Natural eye movements during an examination are used as a cue for super-resolution in a robust maximum a-posteriori scheme. In order to compensate heterogeneous illumination on the fundus, we integrate retrospective illumination correction for photometric registration to the underlying imaging model. Our method utilizes quality self-assessment to provide objective quality scores for reconstructed images as well as to select regularization parameters automatically. In our evaluation on real data acquired from six human subjects with a low-cost video camera, the proposed method achieved considerable enhancements of low-resolution frames and improved noise and sharpness characteristics by 74%. In terms of image analysis, we demonstrate the importance of our method for the improvement of automatic blood vessel segmentation as an example application, where the sensitivity was increased by 13% using super-resolution reconstruction.

An IEC standard on quality assurance for diagnostic X-ray systems

International Nuclear Information System (INIS)

Boer, J.A. den

1985-01-01

A presentation is given of some characteristics of the International Electrotechnical Commission (IEC). This is followed by a short discussion of general aspects of quality assurance in the diagnostic department. From this discussion it becomes apparent to which aspects of quality assurance IEC can contribute. Within that framework a working group of Sub-Committee 62 is at present active in developing a standard on quality assurance for diagnostic X-ray systems. The standard will contain a set of constancy tests that is claimed to allow a balanced quality assurance programme. The democratic procedure of IEC should guarantee that the proposed standard gains wide acceptance. (author)

Modeling the Quality of Videos Displayed With Local Dimming Backlight at Different Peak White and Ambient Light Levels

DEFF Research Database (Denmark)

Mantel, Claire; Søgaard, Jacob; Bech, Søren

2016-01-01

is computed using a model of the display. Widely used objective quality metrics are applied based on the rendering models of the videos to predict the subjective evaluations. As these predictions are not satisfying, three machine learning methods are applied: partial least square regression, elastic net......This paper investigates the impact of ambient light and peak white (maximum brightness of a display) on the perceived quality of videos displayed using local backlight dimming. Two subjective tests providing quality evaluations are presented and analyzed. The analyses of variance show significant...

Architectures for radio over fiber transmission of high-quality video and data signals

DEFF Research Database (Denmark)

Lebedev, Alexander

with a constraint on complexity. For wireless personal area networks distribution, we explore the notion of joint optimization of physical layer parameters of a fiber-wireless link (optical power levels, wireless transmission distance) and the codec parameters (quantization, error-resilience tools) based...... on the peak signal-to-noise ratio as an objective video quality metric for compressed video transmission. Furthermore, we experimentally demonstrate uncompressed 1080i highdefinition video distribution in V-band (50–75 GHz) and W-band (75–110 GHz) fiber-wireless links achieving 3 m of wireless transmission...... efficient wired/wireless backhaul of picocell networks. Gigabit signal transmission is realized in combined fiber-wireless-fiber link enabling simultaneous backhaul of dense metropolitan and suburban areas. In this Thesis, we propose a technique to combat periodic chromatic dispersion-induced radio...

Diagnosing psychogenic nonepileptic seizures: Video-EEG monitoring, suggestive seizure induction and diagnostic certainty.

Science.gov (United States)

Popkirov, Stoyan; Jungilligens, Johannes; Grönheit, Wenke; Wellmer, Jörg

2017-08-01

Psychogenic nonepileptic seizures (PNES) can remain undiagnosed for many years, leading to unnecessary medication and delayed treatment. A recent report by the International League Against Epilepsy Nonepileptic Seizures Task Force recommends a staged approach to the diagnosis of PNES (LaFrance, et al., 2013). We aimed to investigate its practical utility, and to apply the proposed classification to evaluate the role of long-term video-EEG monitoring (VEEG) and suggestive seizure induction (SSI) in PNES workup. Using electronic medical records, 122 inpatients (mean age 36.0±12.9years; 68% women) who received the diagnosis of PNES at our epilepsy center during a 4.3-year time period were included. There was an 82.8% agreement between diagnostic certainty documented at discharge and that assigned retroactively using the Task Force recommendations. In a minority of cases, having used the Task Force criteria could have encouraged the clinicians to give more certain diagnoses, exemplifying the Task Force report's utility. Both VEEG and SSI were effective at supporting high level diagnostic certainty. Interestingly, about one in four patients (26.2%) had a non-diagnostic ("negative") VEEG but a positive SSI. On average, this subgroup did not have significantly shorter mean VEEG recording times than VEEG-positive patients. However, VEEG-negative/SSI-positive patients had a significantly lower habitual seizure frequency than their counterparts. This finding emphasizes the utility of SSI in ascertaining the diagnosis of PNES in patients who do not have a spontaneous habitual event during VEEG due to, for example, low seizure frequency. Copyright © 2017 Elsevier Inc. All rights reserved.

Low-latency video transmission over high-speed WPANs based on low-power video compression

DEFF Research Database (Denmark)

Belyaev, Evgeny; Turlikov, Andrey; Ukhanova, Ann

2010-01-01

This paper presents latency-constrained video transmission over high-speed wireless personal area networks (WPANs). Low-power video compression is proposed as an alternative to uncompressed video transmission. A video source rate control based on MINMAX quality criteria is introduced. Practical...

Effects of music and music video interventions on sleep quality: A randomized controlled trial in adults with sleep disturbances.

Science.gov (United States)

Huang, Chiung-Yu; Chang, En-Ting; Hsieh, Yuan-Mei; Lai, Hui-Ling

2017-10-01

The present study aimed to compare the effects of music and music video interventions on objective and subjective sleep quality in adults with sleep disturbances. A randomized controlled trial was performed on 71 adults who were recruited from the outpatient department of a hospital with 1100 beds and randomly assigned to the control, music, and music video groups. During the 4 test days (Days 2-5), for 30min before nocturnal sleep, the music group listened to Buddhist music and the music video group watched Buddhist music videos. They were instructed to not listen/watch to the music/MV on the first night (pretest, Day 1) and the final night (Day 6). The control group received no intervention. Sleep was assessed using a one-channel electroencephalography machine in their homes and self-reported questionnaires. The music and music video interventions had no effect on any objective sleep parameters, as measured using electroencephalography. However, the music group had significantly longer subjective total sleep time than the music video group did (Wald χ 2 =6.23, p=0.04). Our study results increase knowledge regarding music interventions for sleep quality in adults with sleep disturbances. This study suggested that more research is required to strengthen the scientific knowledge of the effects of music intervention on sleep quality in adults with sleep disturbances. (ISRCTN94971645). Copyright © 2017 Elsevier Ltd. All rights reserved.

Validation of the fifth edition BI-RADS ultrasound lexicon with comparison of fourth and fifth edition diagnostic performance using video clips

International Nuclear Information System (INIS)

Yoon, Jung Hyun; Kim, Min Jung; Lee, Hye Sun; Kim, Sung Hun; Youk, Ji Hyun; Jeong, Sun Hye; Kim, You Me

2016-01-01

The aim of this study was to evaluate the positive predictive value (PPV) and the diagnostic performance of the ultrasonographic descriptors in the fifth edition of BI-RADS, comparing with the fourth edition using video clips. From September 2013 to July 2014, 80 breast masses in 74 women (mean age, 47.5±10.7 years) from five institutions of the Korean Society of Breast Imaging were included. Two radiologists individually reviewed the static and video images and analyzed the images according to the fourth and fifth edition of BI-RADS. The PPV of each descriptor was calculated and diagnostic performances between the fourth and fifth editions were compared. Of the 80 breast masses, 51 (63.8%) were benign and 29 (36.2%) were malignant. Suspicious ultrasonographic features such as irregular shape, non-parallel orientation, angular or spiculated margins, and combined posterior features showed higher PPV in both editions (all P<0.05). No significant differences were found in the diagnostic performances between the two editions (all P>0.05). The area under the receiver operating characteristics curve was higher in the fourth edition (0.708 to 0.690), without significance (P=0.416). The fifth edition of the BI-RADS ultrasound lexicon showed comparable performance to the fourth edition and can be useful in the differential diagnosis of breast masses using ultrasonography

A video Hartmann wavefront diagnostic that incorporates a monolithic microlens array

International Nuclear Information System (INIS)

Toeppen, J.S.; Bliss, E.S.; Long, T.W.; Salmon, J.T.

1991-07-01

we have developed a video Hartmann wavefront sensor that incorporates a monolithic array of microlenses as the focusing elements. The sensor uses a monolithic array of photofabricated lenslets. Combined with a video processor, this system reveals local gradients of the wavefront at a video frame rate of 30 Hz. Higher bandwidth is easily attainable with a camera and video processor that have faster frame rates. When used with a temporal filter, the reconstructed wavefront error is less than 1/10th wave

Flexible Macroblock Ordering for Context-Aware Ultrasound Video Transmission over Mobile WiMAX

Science.gov (United States)

Martini, Maria G.; Hewage, Chaminda T. E. R.

2010-01-01

The most recent network technologies are enabling a variety of new applications, thanks to the provision of increased bandwidth and better management of Quality of Service. Nevertheless, telemedical services involving multimedia data are still lagging behind, due to the concern of the end users, that is, clinicians and also patients, about the low quality provided. Indeed, emerging network technologies should be appropriately exploited by designing the transmission strategy focusing on quality provision for end users. Stemming from this principle, we propose here a context-aware transmission strategy for medical video transmission over WiMAX systems. Context, in terms of regions of interest (ROI) in a specific session, is taken into account for the identification of multiple regions of interest, and compression/transmission strategies are tailored to such context information. We present a methodology based on H.264 medical video compression and Flexible Macroblock Ordering (FMO) for ROI identification. Two different unequal error protection methodologies, providing higher protection to the most diagnostically relevant data, are presented. PMID:20827292

A novel no-reference objective stereoscopic video quality assessment method based on visual saliency analysis

Science.gov (United States)

Yang, Xinyan; Zhao, Wei; Ye, Long; Zhang, Qin

2017-07-01

This paper proposes a no-reference objective stereoscopic video quality assessment method with the motivation that making the effect of objective experiments close to that of subjective way. We believe that the image regions with different visual salient degree should not have the same weights when designing an assessment metric. Therefore, we firstly use GBVS algorithm to each frame pairs and separate both the left and right viewing images into the regions with strong, general and week saliency. Besides, local feature information like blockiness, zero-crossing and depth are extracted and combined with a mathematical model to calculate a quality assessment score. Regions with different salient degree are assigned with different weights in the mathematical model. Experiment results demonstrate the superiority of our method compared with the existed state-of-the-art no-reference objective Stereoscopic video quality assessment methods.

Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization

International Nuclear Information System (INIS)

Holmes, D.R. Jr.; Bove, A.A.; Wondrow, M.A.; Gray, J.E.

1986-01-01

A newly developed video x-ray progressive scanning system improves image quality, decreases radiation exposure, and can be added to any pulsed fluoroscopic x-ray system using a video display without major system modifications. With use of progressive video scanning, the radiation entrance exposure rate measured with a vascular phantom was decreased by 32 to 53% in comparison with a conventional fluoroscopic x-ray system. In addition to this substantial decrease in radiation exposure, the quality of the image was improved because of less motion blur and artifact. Progressive video scanning has the potential for widespread application to all pulsed fluoroscopic x-ray systems. Use of this technique should make cardiac catheterization procedures and all other fluoroscopic procedures safer for the patient and the involved medical and paramedical staff

WE-AB-206-01: Diagnostic Ultrasound Imaging Quality Assurance

Energy Technology Data Exchange (ETDEWEB)

Zagzebski, J. [University of Wisconsin (United States)

2016-06-15

The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. The goal of this ultrasound hands-on workshop is to demonstrate quality control (QC) testing in diagnostic ultrasound and to provide updates in ACR ultrasound accreditation requirements. The first half of this workshop will include two presentations reviewing diagnostic ultrasound QA/QC and ACR ultrasound accreditation requirements. The second half of the workshop will include live demonstrations of basic QC tests. An array of ultrasound testing phantoms and ultrasound scanners will be available for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations and on-site instructors. The targeted attendees are medical physicists in diagnostic imaging. Learning Objectives: Gain familiarity with common elements of a QA/QC program for diagnostic ultrasound imaging dentify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools Learn ACR ultrasound accreditation requirements Jennifer Walter is an employee of American College of Radiology on Ultrasound Accreditation.

WE-AB-206-01: Diagnostic Ultrasound Imaging Quality Assurance

International Nuclear Information System (INIS)

Zagzebski, J.

2016-01-01

The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. The goal of this ultrasound hands-on workshop is to demonstrate quality control (QC) testing in diagnostic ultrasound and to provide updates in ACR ultrasound accreditation requirements. The first half of this workshop will include two presentations reviewing diagnostic ultrasound QA/QC and ACR ultrasound accreditation requirements. The second half of the workshop will include live demonstrations of basic QC tests. An array of ultrasound testing phantoms and ultrasound scanners will be available for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations and on-site instructors. The targeted attendees are medical physicists in diagnostic imaging. Learning Objectives: Gain familiarity with common elements of a QA/QC program for diagnostic ultrasound imaging dentify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools Learn ACR ultrasound accreditation requirements Jennifer Walter is an employee of American College of Radiology on Ultrasound Accreditation.

Web-based video monitoring of CT and MRI procedures

Science.gov (United States)

Ratib, Osman M.; Dahlbom, Magdalena; Kho, Hwa T.; Valentino, Daniel J.; McCoy, J. Michael

2000-05-01

A web-based video transmission of images from CT and MRI consoles was implemented in an Intranet environment for real- time monitoring of ongoing procedures. Images captured from the consoles are compressed to video resolution and broadcasted through a web server. When called upon, the attending radiologists can view these live images on any computer within the secured Intranet network. With adequate compression, these images can be displayed simultaneously in different locations at a rate of 2 to 5 images/sec through standard LAN. The quality of the images being insufficient for diagnostic purposes, our users survey showed that they were suitable for supervising a procedure, positioning the imaging slices and for routine quality checking before completion of a study. The system was implemented at UCLA to monitor 9 CTs and 6 MRIs distributed in 4 buildings. This system significantly improved the radiologists productivity by saving precious time spent in trips between reading rooms and examination rooms. It also improved patient throughput by reducing the waiting time for the radiologists to come to check a study before moving the patient from the scanner.

ATM Quality of Service Tests for Digitized Video Using ATM Over Satellite: Laboratory Tests

Science.gov (United States)

Ivancic, William D.; Brooks, David E.; Frantz, Brian D.

1997-01-01

A digitized video application was used to help determine minimum quality of service parameters for asynchronous transfer mode (ATM) over satellite. For these tests, binomially distributed and other errors were digitally inserted in an intermediate frequency link via a satellite modem and a commercial gaussian noise generator. In this paper, the relation- ship between the ATM cell error and cell loss parameter specifications is discussed with regard to this application. In addition, the video-encoding algorithms, test configurations, and results are presented in detail.

Efficient data replication for the delivery of high-quality video content over P2P VoD advertising networks

Science.gov (United States)

Ho, Chien-Peng; Yu, Jen-Yu; Lee, Suh-Yin

2011-12-01

Recent advances in modern television systems have had profound consequences for the scalability, stability, and quality of transmitted digital data signals. This is of particular significance for peer-to-peer (P2P) video-on-demand (VoD) related platforms, faced with an immediate and growing demand for reliable service delivery. In response to demands for high-quality video, the key objectives in the construction of the proposed framework were user satisfaction with perceived video quality and the effective utilization of available resources on P2P VoD networks. This study developed a peer-based promoter to support online advertising in P2P VoD networks based on an estimation of video distortion prior to the replication of data stream chunks. The proposed technology enables the recovery of lost video using replicated stream chunks in real time. Load balance is achieved by adjusting the replication level of each candidate group according to the degree-of-distortion, thereby enabling a significant reduction in server load and increased scalability in the P2P VoD system. This approach also promotes the use of advertising as an efficient tool for commercial promotion. Results indicate that the proposed system efficiently satisfies the given fault tolerances.

Image quality assessment for video stream recognition systems

Science.gov (United States)

Chernov, Timofey S.; Razumnuy, Nikita P.; Kozharinov, Alexander S.; Nikolaev, Dmitry P.; Arlazarov, Vladimir V.

2018-04-01

Recognition and machine vision systems have long been widely used in many disciplines to automate various processes of life and industry. Input images of optical recognition systems can be subjected to a large number of different distortions, especially in uncontrolled or natural shooting conditions, which leads to unpredictable results of recognition systems, making it impossible to assess their reliability. For this reason, it is necessary to perform quality control of the input data of recognition systems, which is facilitated by modern progress in the field of image quality evaluation. In this paper, we investigate the approach to designing optical recognition systems with built-in input image quality estimation modules and feedback, for which the necessary definitions are introduced and a model for describing such systems is constructed. The efficiency of this approach is illustrated by the example of solving the problem of selecting the best frames for recognition in a video stream for a system with limited resources. Experimental results are presented for the system for identity documents recognition, showing a significant increase in the accuracy and speed of the system under simulated conditions of automatic camera focusing, leading to blurring of frames.

ICT diagnostic method of beryllium welding quality

International Nuclear Information System (INIS)

Sun Lingxia; Wei Kentang; Ye Yunchang

2002-01-01

To avoid the interference of high density material for the quality assay of beryllium welding line, a slice by slice scanning method was proposed based upon the research results of the Industrial Computerized Tomography (ICT) diagnostics for weld penetration, weld width, off-centered deviation and weld defects of beryllium-ring welding seam with high density material inside

Quality control in diagnostic radiology: software (Visual Basic 6) and database applications

International Nuclear Information System (INIS)

Md Saion Salikin; Muhammad Farid Abdul Khalid

2002-01-01

Quality Assurance programme in diagnostic Radiology is being implemented by the Ministry of Health (MoH) in Malaysia. Under this program the performance of an x-ray machine used for diagnostic purpose is tested by using the approved procedure which is commonly known as Quality Control in diagnostic radiology. The quality control or performance tests are carried out b a class H licence holder issued the Atomic Energy Licensing Act 1984. There are a few computer applications (software) that are available in the market which can be used for this purpose. A computer application (software) using Visual Basics 6 and Microsoft Access, is being developed to expedite data handling, analysis and storage as well as report writing of the quality control tests. In this paper important features of the software for quality control tests are explained in brief. A simple database is being established for this purpose which is linked to the software. Problems encountered in the preparation of database are discussed in this paper. A few examples of practical usage of the software and database applications are presented in brief. (Author)

Part Two: Learning Science Through Digital Video: Student Views on Watching and Creating Videos

Science.gov (United States)

Wade, P.; Courtney, A. R.

2014-12-01

The use of digital video for science education has become common with the wide availability of video imagery. This study continues research into aspects of using digital video as a primary teaching tool to enhance student learning in undergraduate science courses. Two survey instruments were administered to undergraduate non-science majors. Survey One focused on: a) What science is being learned from watching science videos such as a "YouTube" clip of a volcanic eruption or an informational video on geologic time and b) What are student preferences with regard to their learning (e.g. using video versus traditional modes of delivery)? Survey Two addressed students' perspectives on the storytelling aspect of the video with respect to: a) sustaining interest, b) providing science information, c) style of video and d) quality of the video. Undergraduate non-science majors were the primary focus group in this study. Students were asked to view video segments and respond to a survey focused on what they learned from the segments. The storytelling aspect of each video was also addressed by students. Students watched 15-20 shorter (3-15 minute science videos) created within the last four years. Initial results of this research support that shorter video segments were preferred and the storytelling quality of each video related to student learning.

Modeling the Color Image and Video Quality on Liquid Crystal Displays with Backlight Dimming

DEFF Research Database (Denmark)

Korhonen, Jari; Mantel, Claire; Burini, Nino

2013-01-01

Objective image and video quality metrics focus mostly on the digital representation of the signal. However, the display characteristics are also essential for the overall Quality of Experience (QoE). In this paper, we use a model of a backlight dimming system for Liquid Crystal Display (LCD......) and show how the modeled image can be used as an input to quality assessment algorithms. For quality assessment, we propose an image quality metric, based on Peak Signal-to-Noise Ratio (PSNR) computation in the CIE L*a*b* color space. The metric takes luminance reduction, color distortion and loss...

Video steganography based on bit-plane decomposition of wavelet-transformed video

Science.gov (United States)

Noda, Hideki; Furuta, Tomofumi; Niimi, Michiharu; Kawaguchi, Eiji

2004-06-01

This paper presents a steganography method using lossy compressed video which provides a natural way to send a large amount of secret data. The proposed method is based on wavelet compression for video data and bit-plane complexity segmentation (BPCS) steganography. BPCS steganography makes use of bit-plane decomposition and the characteristics of the human vision system, where noise-like regions in bit-planes of a dummy image are replaced with secret data without deteriorating image quality. In wavelet-based video compression methods such as 3-D set partitioning in hierarchical trees (SPIHT) algorithm and Motion-JPEG2000, wavelet coefficients in discrete wavelet transformed video are quantized into a bit-plane structure and therefore BPCS steganography can be applied in the wavelet domain. 3-D SPIHT-BPCS steganography and Motion-JPEG2000-BPCS steganography are presented and tested, which are the integration of 3-D SPIHT video coding and BPCS steganography, and that of Motion-JPEG2000 and BPCS, respectively. Experimental results show that 3-D SPIHT-BPCS is superior to Motion-JPEG2000-BPCS with regard to embedding performance. In 3-D SPIHT-BPCS steganography, embedding rates of around 28% of the compressed video size are achieved for twelve bit representation of wavelet coefficients with no noticeable degradation in video quality.

Radiation safety and quality control assurance in X-ray diagnostics 1998

International Nuclear Information System (INIS)

Servomaa, A.

1998-03-01

The report is based on a seminar course of lectures 'Radiation safety and quality assurance in X-ray diagnostics 1998' organized by the Radiation and Nuclear Safety Authority (STUK) in Finland. The lectures included actual information on X-ray examinations: methods of quality assurance, methods of measuring and calculating patient doses, examination frequencies, patient doses, occupational doses, and radiation risks. Paediatric X-ray examinations and interventional procedures were the most specific topics. The new Council Directive 97/43/Euratom on medical exposure, and the European Guidelines on quality criteria for diagnostic radiographic images, were discussed in several lectures. Lectures on general radiation threats and preparedness, examples of radiation accidents, and emergency preparedness in hospitals were also included. (editor)

Rheumatoid Arthritis Educational Video Series

Science.gov (United States)

... Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos ... Your Arthritis Managing Chronic Pain and Depression in Arthritis Nutrition & Rheumatoid Arthritis Arthritis and Health-related Quality of Life ...

Implementation of the quality control of diagnostic monitors

International Nuclear Information System (INIS)

Ramos Pacho, J. A.; Gomez Llorente, P. L.; Gomez Llorente, N.; Cons Perez, N.; Verde Velasco, J. M.; Perez Alvarez, M. E.; Delgado Aparicio, J. M.; Garcia Repiso, S.; Montes Fuentes, C.; Martin Rincon, C.

2013-01-01

The optimization of the quality of Radiology is aimed at obtaining greater diagnostic information minimizing the risks to the patient. This is essential, among other factors, not only that the image acquisition system works properly, but that the display device is capable of representing the information contained. (Author)

Unsupervised deep learning for real-time assessment of video streaming services

NARCIS (Netherlands)

Torres Vega, M.; Mocanu, D.C.; Liotta, A.

2017-01-01

Evaluating quality of experience in video streaming services requires a quality metric that works in real time and for a broad range of video types and network conditions. This means that, subjective video quality assessment studies, or complex objective video quality assessment metrics, which would

Quality control procedures of dental diagnostic radiology systems

International Nuclear Information System (INIS)

Andrade, Paula Serra Sasaki

2007-01-01

This work presents quality control reference procedures for dental diagnostic radiology systems, following the recommendations of the Publication 453 of the Brazilian Health Ministry (PF453), to be applied in dental clinics, in order to achieve an improvement in the radiological image qualities and the patient dose reduction. All tests were applied in an intraoral X rays system, following the methodology developed and the requirements of the PF 453. In order to verify the best quality of the image in relation to the smaller exposition time an object test was also developed in this work. The use of this object allowed the reduction of the exposition time of 0.5 seconds, the maximum value of the linear region of the characteristic curve, for 0.2 seconds. The tested X rays system showed a very good agreement with the applied procedures, detaching the reduction of the skin entrance dose using the film-holding devices. However, the size of the field increased and exceeded the maximum value of 6 cm recommended in the standard. The importance of the quality control in dental diagnostic radiology systems is essential due to the constant use of X radiation in dental clinics. The PF453 recommends the frequency of at least two years for the constancy tests. However, it is suggested that the professional, surgeon-dentist, should be responsible for the internal control of the image quality obtained from the X rays device. This can be done through monthly exposures of the object test developed in this work. (author)

Rheumatoid Arthritis Educational Video Series

Medline Plus

Full Text Available ... Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos ... Your Arthritis Managing Chronic Pain and Depression in Arthritis Nutrition & Rheumatoid Arthritis Arthritis and Health-related Quality of Life ...

Enhancement system of nighttime infrared video image and visible video image

Science.gov (United States)

Wang, Yue; Piao, Yan

2016-11-01

Visibility of Nighttime video image has a great significance for military and medicine areas, but nighttime video image has so poor quality that we can't recognize the target and background. Thus we enhance the nighttime video image by fuse infrared video image and visible video image. According to the characteristics of infrared and visible images, we proposed improved sift algorithm andαβ weighted algorithm to fuse heterologous nighttime images. We would deduced a transfer matrix from improved sift algorithm. The transfer matrix would rapid register heterologous nighttime images. And theαβ weighted algorithm can be applied in any scene. In the video image fusion system, we used the transfer matrix to register every frame and then used αβ weighted method to fuse every frame, which reached the time requirement soft video. The fused video image not only retains the clear target information of infrared video image, but also retains the detail and color information of visible video image and the fused video image can fluency play.

Quality optimization of H.264/AVC video transmission over noisy environments using a sparse regression framework

Science.gov (United States)

Pandremmenou, K.; Tziortziotis, N.; Paluri, S.; Zhang, W.; Blekas, K.; Kondi, L. P.; Kumar, S.

2015-03-01

We propose the use of the Least Absolute Shrinkage and Selection Operator (LASSO) regression method in order to predict the Cumulative Mean Squared Error (CMSE), incurred by the loss of individual slices in video transmission. We extract a number of quality-relevant features from the H.264/AVC video sequences, which are given as input to the LASSO. This method has the benefit of not only keeping a subset of the features that have the strongest effects towards video quality, but also produces accurate CMSE predictions. Particularly, we study the LASSO regression through two different architectures; the Global LASSO (G.LASSO) and Local LASSO (L.LASSO). In G.LASSO, a single regression model is trained for all slice types together, while in L.LASSO, motivated by the fact that the values for some features are closely dependent on the considered slice type, each slice type has its own regression model, in an e ort to improve LASSO's prediction capability. Based on the predicted CMSE values, we group the video slices into four priority classes. Additionally, we consider a video transmission scenario over a noisy channel, where Unequal Error Protection (UEP) is applied to all prioritized slices. The provided results demonstrate the efficiency of LASSO in estimating CMSE with high accuracy, using only a few features. les that typically contain high-entropy data, producing a footprint that is far less conspicuous than existing methods. The system uses a local web server to provide a le system, user interface and applications through an web architecture.

Perceptual quality estimation of H.264/AVC videos using reduced-reference and no-reference models

Science.gov (United States)

Shahid, Muhammad; Pandremmenou, Katerina; Kondi, Lisimachos P.; Rossholm, Andreas; Lövström, Benny

2016-09-01

Reduced-reference (RR) and no-reference (NR) models for video quality estimation, using features that account for the impact of coding artifacts, spatio-temporal complexity, and packet losses, are proposed. The purpose of this study is to analyze a number of potentially quality-relevant features in order to select the most suitable set of features for building the desired models. The proposed sets of features have not been used in the literature and some of the features are used for the first time in this study. The features are employed by the least absolute shrinkage and selection operator (LASSO), which selects only the most influential of them toward perceptual quality. For comparison, we apply feature selection in the complete feature sets and ridge regression on the reduced sets. The models are validated using a database of H.264/AVC encoded videos that were subjectively assessed for quality in an ITU-T compliant laboratory. We infer that just two features selected by RR LASSO and two bitstream-based features selected by NR LASSO are able to estimate perceptual quality with high accuracy, higher than that of ridge, which uses more features. The comparisons with competing works and two full-reference metrics also verify the superiority of our models.

A Survey of Standardized Approaches towards the Quality of Experience Evaluation for Video Services: An ITU Perspective

Directory of Open Access Journals (Sweden)

Debajyoti Pal

2018-01-01

Full Text Available Over the past few years there has been an exponential increase in the amount of multimedia data being streamed over the Internet. At the same time, we are also witnessing a change in the way quality of any particular service is interpreted, with more emphasis being given to the end-users. Thus, silently there has been a paradigm shift from the traditional Quality of Service approach (QoS towards a Quality of Experience (QoE model while evaluating the service quality. A lot of work that tries to evaluate the quality of audio, video, and multimedia services over the Internet has been done. At the same time, research is also going on trying to map the two different domains of quality metrics, i.e., the QoS and QoE domain. Apart from the work done by individual researchers, the International Telecommunications Union (ITU has been quite active in this area of quality assessment. This is obvious from the large number of ITU standards that are available for different application types. The sheer variety of techniques being employed by ITU as well as other researchers sometimes tends to be too complex and diversified. Although there are survey papers that try to present the current state of the art methodologies for video quality evaluation, none has focused on the ITU perspective. In this work, we try to fill up this void by presenting up-to-date information on the different measurement methods that are currently being employed by ITU for a video streaming scenario. We highlight the outline of each method with sufficient detail and try to analyze the challenges being faced along with the direction of future research.

Validation of the fifth edition BI-RADS ultrasound lexicon with comparison of fourth and fifth edition diagnostic performance using video clips

Directory of Open Access Journals (Sweden)

Jung Hyun Yoon

2016-10-01

Full Text Available Purpose The aim of this study was to evaluate the positive predictive value (PPV and the diagnostic performance of the ultrasonographic descriptors in the fifth edition of BI-RADS, comparing with the fourth edition using video clips. Methods From September 2013 to July 2014, 80 breast masses in 74 women (mean age, 47.5±10.7 years from five institutions of the Korean Society of Breast Imaging were included. Two radiologists individually reviewed the static and video images and analyzed the images according to the fourth and fifth edition of BI-RADS. The PPV of each descriptor was calculated and diagnostic performances between the fourth and fifth editions were compared. Results Of the 80 breast masses, 51 (63.8% were benign and 29 (36.2% were malignant. Suspicious ultrasonographic features such as irregular shape, non-parallel orientation, angular or spiculated margins, and combined posterior features showed higher PPV in both editions (all P0.05. The area under the receiver operating characteristics curve was higher in the fourth edition (0.708 to 0.690, without significance (P=0.416. Conclusion The fifth edition of the BI-RADS ultrasound lexicon showed comparable performance to the fourth edition and can be useful in the differential diagnosis of breast masses using ultrasonography.

Characterization of radiation qualities used in diagnostic X-ray

International Nuclear Information System (INIS)

Bero, M.; Zahili, M.; Al Ahmad, M.

2013-12-01

This study aims to adjust the radiation beams emitted from X-ray tubes installed at the National Radiation Metrology Laboratory in the field of diagnostic radiology (radiology and mammography) according to the IAEA protocol code number TRS 457, the second goal of this study is to establish various radiation qualities used fordiagnostic radiology applications: RQR, RQA and RQT and the radiation qualities related to mammography applications: RQA-M and RQR-M (author).

Quality of information accompanying on-line marketing of home diagnostic tests.

Science.gov (United States)

Datta, Adrija K; Selman, Tara J; Kwok, Tony; Tang, Teresa; Khan, Khalid S

2008-01-01

To assess the quality of information provided to consumers by websites marketing medical home diagnostic tests. A cross-sectional analysis of a database developed from searching targeted websites. Data sources were websites written in English which marketed medical home diagnostic tests. A meta-search engine was used to identify the first 20 citations for each type of home diagnostic medical test. Relevant websites limited to those written in English were reviewed independently and in triplicate, with disputes resolved by two further reviewers. Information on the quality of these sites was extracted using a pre-piloted performer. 168 websites were suitable for inclusion in the review. The quality of these sites showed marked variation. Only 24 of 168 (14.2%) complied with at least three-quarters of the quality items and just over half (95 of 168, 56.5%) reported official approval or certification of the test. Information on accuracy of the test marketed was reported by 87 of 168 (51.7%) websites, with 15 of 168 (8.9%) providing a scientific reference. Instructions for use of the product were found in 97 of 168 (57.9%). However, the course of action to be taken after obtaining the test result was stated in only 63 of 168 (37.5%) for a positive result and 43 of 168 (25.5%) for a negative result. The quality of information posted on commercial websites marketing home tests online is unsatisfactory and potentially misleading for consumers.

Extracting a Good Quality Frontal Face Image from a Low-Resolution Video Sequence

DEFF Research Database (Denmark)

Nasrollahi, Kamal; Moeslund, Thomas B.

2011-01-01

Feeding low-resolution and low-quality images, from inexpensive surveillance cameras, to systems like, e.g., face recognition, produces erroneous and unstable results. Therefore, there is a need for a mechanism to bridge the gap between on one hand low-resolution and low-quality images......, we use a learning-based super-resolution algorithm applied to the result of the reconstruction-based part to improve the quality by another factor of two. This results in an improvement factor of four for the entire system. The proposed system has been tested on 122 low-resolution sequences from two...... different databases. The experimental results show that the proposed system can indeed produce a high-resolution and good quality frontal face image from low-resolution video sequences....

Subjective quality of video sequences rendered on LCD with local backlight dimming at different lighting conditions

Science.gov (United States)

Mantel, Claire; Korhonen, Jari; Pedersen, Jesper M.; Bech, Søren; Andersen, Jakob Dahl; Forchhammer, Søren

2015-01-01

This paper focuses on the influence of ambient light on the perceived quality of videos displayed on Liquid Crystal Display (LCD) with local backlight dimming. A subjective test assessing the quality of videos with two backlight dimming methods and three lighting conditions, i.e. no light, low light level (5 lux) and higher light level (60 lux) was organized to collect subjective data. Results show that participants prefer the method exploiting local dimming possibilities to the conventional full backlight but that this preference varies depending on the ambient light level. The clear preference for one method at the low light conditions decreases at the high ambient light, confirming that the ambient light significantly attenuates the perception of the leakage defect (light leaking through dark pixels). Results are also highly dependent on the content of the sequence, which can modulate the effect of the ambient light from having an important influence on the quality grades to no influence at all.

Tree-structured vector quantization of CT chest scans: Image quality and diagnostic accuracy

International Nuclear Information System (INIS)

Cosman, P.C.; Tseng, C.; Gray, R.M.; Olshen, R.A.; Moses, L.E.; Davidson, H.C.; Bergin, C.J.; Riskin, E.A.

1993-01-01

The quality of lossy compressed images is often characterized by signal-to-noise ratios, informal tests of subjective quality, or receiver operating characteristic (ROC) curves that include subjective appraisals of the value of an image for a particular application. The authors believe that for medical applications, lossy compressed images should be judged by a more natural and fundamental aspect of relative image quality: their use in making accurate diagnoses. They apply a lossy compression algorithm to medical images, and quantify the quality of the images by the diagnostic performance of radiologists, as well as by traditional signal-to-noise ratios and subjective ratings. The study is unlike previous studies of the effects of lossy compression in that they consider non-binary detection tasks, simulate actual diagnostic practice instead of using paired tests or confidence rankings, use statistical methods that are more appropriate for non-binary clinical data than are the popular ROC curves, and use low-complexity predictive tree-structured vector quantization for compression rather than DCT-based transform codes combined with entropy coding. Their diagnostic tasks are the identification of nodules (tumors) in the lungs and lymphadenopathy in the mediastinum from computerized tomography (CT) chest scans. For the image modality, compression algorithm, and diagnostic tasks they consider, the original 12 bit per pixel (bpp) CT image can be compressed to between 1 bpp and 2 bpp with no significant changes in diagnostic accuracy

Intelligent control for scalable video processing

NARCIS (Netherlands)

Wüst, C.C.

2006-01-01

In this thesis we study a problem related to cost-effective video processing in software by consumer electronics devices, such as digital TVs. Video processing is the task of transforming an input video signal into an output video signal, for example to improve the quality of the signal. This

Moving beyond quality control in diagnostic radiology and the role of the clinically qualified medical physicist.

Science.gov (United States)

Delis, H; Christaki, K; Healy, B; Loreti, G; Poli, G L; Toroi, P; Meghzifene, A

2017-09-01

Quality control (QC), according to ISO definitions, represents the most basic level of quality. It is considered to be the snapshot of the performance or the characteristics of a product or service, in order to verify that it complies with the requirements. Although it is usually believed that "the role of medical physicists in Diagnostic Radiology is QC", this, not only limits the contribution of medical physicists, but is also no longer adequate to meet the needs of Diagnostic Radiology in terms of Quality. In order to assure quality practices more organized activities and efforts are required in the modern era of diagnostic radiology. The complete system of QC is just one element of a comprehensive quality assurance (QA) program that aims at ensuring that the requirements of quality of a product or service will consistently be fulfilled. A comprehensive Quality system, starts even before the procurement of any equipment, as the need analysis and the development of specifications are important components under the QA framework. Further expanding this framework of QA, a comprehensive Quality Management System can provide additional benefits to a Diagnostic Radiology service. Harmonized policies and procedures and elements such as mission statement or job descriptions can provide clarity and consistency in the services provided, enhancing the outcome and representing a solid platform for quality improvement. The International Atomic Energy Agency (IAEA) promotes this comprehensive quality approach in diagnostic imaging and especially supports the field of comprehensive clinical audits as a tool for quality improvement. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

About subjective evaluation of adaptive video streaming

Science.gov (United States)

Tavakoli, Samira; Brunnström, Kjell; Garcia, Narciso

2015-03-01

The usage of HTTP Adaptive Streaming (HAS) technology by content providers is increasing rapidly. Having available the video content in multiple qualities, using HAS allows to adapt the quality of downloaded video to the current network conditions providing smooth video-playback. However, the time-varying video quality by itself introduces a new type of impairment. The quality adaptation can be done in different ways. In order to find the best adaptation strategy maximizing users perceptual quality it is necessary to investigate about the subjective perception of adaptation-related impairments. However, the novelties of these impairments and their comparably long time duration make most of the standardized assessment methodologies fall less suited for studying HAS degradation. Furthermore, in traditional testing methodologies, the quality of the video in audiovisual services is often evaluated separated and not in the presence of audio. Nevertheless, the requirement of jointly evaluating the audio and the video within a subjective test is a relatively under-explored research field. In this work, we address the research question of determining the appropriate assessment methodology to evaluate the sequences with time-varying quality due to the adaptation. This was done by studying the influence of different adaptation related parameters through two different subjective experiments using a methodology developed to evaluate long test sequences. In order to study the impact of audio presence on quality assessment by the test subjects, one of the experiments was done in the presence of audio stimuli. The experimental results were subsequently compared with another experiment using the standardized single stimulus Absolute Category Rating (ACR) methodology.

Development of P4140 video data wall projector; Video data wall projector

Energy Technology Data Exchange (ETDEWEB)

Watanabe, H.; Inoue, H. [Toshiba Corp., Tokyo (Japan)

1998-12-01

The P4140 is a 3 cathode-ray tube (CRT) video data wall projector for super video graphics array (SVGA) signals. It is used as an image display unit, providing a large screen when several sets are put together. A high-quality picture has been realized by higher resolution and improved color uniformity technology. A new convergence adjustment system has also been developed through the optimal combination of digital and analog technologies. This video data wall installation has been greatly enhanced by the automation of cubes and cube performance settings. The P4140 video data wall projector can be used for displaying not only data but video as well. (author)

Toward enhancing the distributed video coder under a multiview video codec framework

Science.gov (United States)

Lee, Shih-Chieh; Chen, Jiann-Jone; Tsai, Yao-Hong; Chen, Chin-Hua

2016-11-01

The advance of video coding technology enables multiview video (MVV) or three-dimensional television (3-D TV) display for users with or without glasses. For mobile devices or wireless applications, a distributed video coder (DVC) can be utilized to shift the encoder complexity to decoder under the MVV coding framework, denoted as multiview distributed video coding (MDVC). We proposed to exploit both inter- and intraview video correlations to enhance side information (SI) and improve the MDVC performance: (1) based on the multiview motion estimation (MVME) framework, a categorized block matching prediction with fidelity weights (COMPETE) was proposed to yield a high quality SI frame for better DVC reconstructed images. (2) The block transform coefficient properties, i.e., DCs and ACs, were exploited to design the priority rate control for the turbo code, such that the DVC decoding can be carried out with fewest parity bits. In comparison, the proposed COMPETE method demonstrated lower time complexity, while presenting better reconstructed video quality. Simulations show that the proposed COMPETE can reduce the time complexity of MVME to 1.29 to 2.56 times smaller, as compared to previous hybrid MVME methods, while the image peak signal to noise ratios (PSNRs) of a decoded video can be improved 0.2 to 3.5 dB, as compared to H.264/AVC intracoding.

Learning to Swim Using Video Modelling and Video Feedback within a Self-Management Program

Science.gov (United States)

Lao, So-An; Furlonger, Brett E.; Moore, Dennis W.; Busacca, Margherita

2016-01-01

Although many adults who cannot swim are primarily interested in learning by direct coaching there are options that have a focus on self-directed learning. As an alternative a self-management program combined with video modelling, video feedback and high quality and affordable video technology was used to assess its effectiveness to assisting an…

Adaptive live multicast video streaming of SVC with UEP FEC

Science.gov (United States)

Lev, Avram; Lasry, Amir; Loants, Maoz; Hadar, Ofer

2014-09-01

Ideally, video streaming systems should provide the best quality video a user's device can handle without compromising on downloading speed. In this article, an improved video transmission system is presented which dynamically enhances the video quality based on a user's current network state and repairs errors from data lost in the video transmission. The system incorporates three main components: Scalable Video Coding (SVC) with three layers, multicast based on Receiver Layered Multicast (RLM) and an UnEqual Forward Error Correction (FEC) algorithm. The SVC provides an efficient method for providing different levels of video quality, stored as enhancement layers. In the presented system, a proportional-integral-derivative (PID) controller was implemented to dynamically adjust the video quality, adding or subtracting quality layers as appropriate. In addition, an FEC algorithm was added to compensate for data lost in transmission. A two dimensional FEC was used. The FEC algorithm came from the Pro MPEG code of practice #3 release 2. Several bit errors scenarios were tested (step function, cosine wave) with different bandwidth size and error values were simulated. The suggested scheme which includes SVC video encoding with 3 layers over IP Multicast with Unequal FEC algorithm was investigated under different channel conditions, variable bandwidths and different bit error rates. The results indicate improvement of the video quality in terms of PSNR over previous transmission schemes.

YouTube and food allergy: An appraisal of the educational quality of information.

Science.gov (United States)

Reddy, Keerthi; Kearns, Mary; Alvarez-Arango, Santiago; Carrillo-Martin, Ismael; Cuervo-Pardo, Nathaly; Cuervo-Pardo, Lyda; Dimov, Ves; Lang, David M; Lopez-Alvarez, Sonia; Schroer, Brian; Mohan, Kaushik; Dula, Mark; Zheng, Simin; Kozinetz, Claudia; Gonzalez-Estrada, Alexei

2018-03-07

Food allergy affects an estimated 8% of children and 3% of adults in the United States. Food-allergic individuals increasingly use the web for medical information. We sought to determine the educational quality of food allergy YouTube videos. We performed a YouTube search using keywords "food allergy" and "food allergies". The 300 most viewed videos were included and analyzed for characteristics, source, and content. Source was further classified as healthcare provider, alternative medicine provider, patient, company, media, and professional society. A scoring system (FA-DQS) was created to evaluate quality (-10 to +34 points). Negative points were assigned for misleading information. Eight reviewers scored each video independently. Three hundred videos were analyzed, with a median of 6351.50 views, 19 likes, and 1 dislike. More video presenters were female (54.3%). The most common type of video source was alternative medicine provider (26.3%). Alternative treatments included the following: water fast, juicing, Ayurveda, apple cider, yoga, visualization, and sea moss. Controversial diagnostics included kinesiology, IgG testing, and pulse test. Almost half of the videos depicted a non-IgE-mediated reaction (49.0%).Videos by professional societies had the highest FA-DQS (7.27). Scores for videos by professional societies were significantly different from other sources (P quality, evidence-based, educational videos on food allergy. © 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Preliminary study on effects of 60Co γ-irradiation on video quality and the image de-noising methods

International Nuclear Information System (INIS)

Yuan Mei; Zhao Jianbin; Cui Lei

2011-01-01

There will be variable noises appear on images in video once the play device irradiated by γ-rays, so as to affect the image clarity. In order to eliminate the image noising, the affection mechanism of γ-irradiation on video-play device was studied in this paper and the methods to improve the image quality with both hardware and software were proposed by use of protection program and de-noising algorithm. The experimental results show that the scheme of video de-noising based on hardware and software can improve effectively the PSNR by 87.5 dB. (authors)

An overview of the International Electrotechnical Commission's activities on quality assurance in diagnostic radiology

International Nuclear Information System (INIS)

Julius, H.W.; Ammers, H. van; Henshaw, E.T.

1989-01-01

In 1981, the International Electrotechnical Commission Sub-committee 62B set up a Working Group (WG 10) to deal with quality assurance in diagnostic X-ray departments and, more specifically, to develop international standards describing procedures to test the constancy of parameters of diagnostic X-ray installations. Since then, the working group has produced a report on General Aspects of Quality Assurance in Diagnostic X-ray Departments and four draft standards on specific topics, while seven more documents are in advanced drafting stage. Several others are presently under consideration. According to the approach adopted by the Working Group, these documents are meant to assist in establishing quality assurance programmes in hospitals and provide guidance on how to perform the tests and interpret their results. This paper reveals the general philosophy behind the activities of the Working Group as well as some details of the standard produced so far, with emphasis on the physical parameters of diagnostic X-ray installations and their proposed criteria for satisfactory performance. (author)

Evaluating radiographers' diagnostic accuracy in screen-reading mammograms: what constitutes a quality study?

International Nuclear Information System (INIS)

Debono, Josephine C; Poulos, Ann E

2015-01-01

The aim of this study was to first evaluate the quality of studies investigating the diagnostic accuracy of radiographers as mammogram screen-readers and then to develop an adapted tool for determining the quality of screen-reading studies. A literature search was used to identify relevant studies and a quality evaluation tool constructed by combining the criteria for quality of Whiting, Rutjes, Dinnes et al. and Brealey and Westwood. This constructed tool was then applied to the studies and subsequently adapted specifically for use in evaluating quality in studies investigating diagnostic accuracy of screen-readers. Eleven studies were identified and the constructed tool applied to evaluate quality. This evaluation resulted in the identification of quality issues with the studies such as potential for bias, applicability of results, study conduct, reporting of the study and observer characteristics. An assessment of the applicability and relevance of the tool for this area of research resulted in adaptations to the criteria and the development of a tool specifically for evaluating diagnostic accuracy in screen-reading. This tool, with further refinement and rigorous validation can make a significant contribution to promoting well-designed studies in this important area of research and practice

A New Dual-purpose Quality Control Dosimetry Protocol for Diagnostic Reference-level Determination in Computed Tomography.

Science.gov (United States)

Sohrabi, Mehdi; Parsi, Masoumeh; Sina, Sedigheh

2018-05-17

A diagnostic reference level is an advisory dose level set by a regulatory authority in a country as an efficient criterion for protection of patients from unwanted medical exposure. In computed tomography, the direct dose measurement and data collection methods are commonly applied for determination of diagnostic reference levels. Recently, a new quality-control-based dose survey method was proposed by the authors to simplify the diagnostic reference-level determination using a retrospective quality control database usually available at a regulatory authority in a country. In line with such a development, a prospective dual-purpose quality control dosimetry protocol is proposed for determination of diagnostic reference levels in a country, which can be simply applied by quality control service providers. This new proposed method was applied to five computed tomography scanners in Shiraz, Iran, and diagnostic reference levels for head, abdomen/pelvis, sinus, chest, and lumbar spine examinations were determined. The results were compared to those obtained by the data collection and quality-control-based dose survey methods, carried out in parallel in this study, and were found to agree well within approximately 6%. This is highly acceptable for quality-control-based methods according to International Atomic Energy Agency tolerance levels (±20%).

Scalable video on demand adaptive Internet-based distribution

CERN Document Server

Zink, Michael

2013-01-01

In recent years, the proliferation of available video content and the popularity of the Internet have encouraged service providers to develop new ways of distributing content to clients. Increasing video scaling ratios and advanced digital signal processing techniques have led to Internet Video-on-Demand applications, but these currently lack efficiency and quality. Scalable Video on Demand: Adaptive Internet-based Distribution examines how current video compression and streaming can be used to deliver high-quality applications over the Internet. In addition to analysing the problems

Quality of information accompanying on-line marketing of home diagnostic tests

Science.gov (United States)

Datta, Adrija K; Selman, Tara J; Kwok, Tony; Tang, Teresa; Khan, Khalid S

2008-01-01

Objective To assess the quality of information provided to consumers by websites marketing medical home diagnostic tests. Design A cross-sectional analysis of a database developed from searching targeted websites. Setting Data sources were websites written in English which marketed medical home diagnostic tests. Main outcome measures A meta-search engine was used to identify the first 20 citations for each type of home diagnostic medical test. Relevant websites limited to those written in English were reviewed independently and in triplicate, with disputes resolved by two further reviewers. Information on the quality of these sites was extracted using a pre-piloted performer. Results 168 websites were suitable for inclusion in the review. The quality of these sites showed marked variation. Only 24 of 168 (14.2%) complied with at least three-quarters of the quality items and just over half (95 of 168, 56.5%) reported official approval or certification of the test. Information on accuracy of the test marketed was reported by 87 of 168 (51.7%) websites, with 15 of 168 (8.9%) providing a scientific reference. Instructions for use of the product were found in 97 of 168 (57.9%). However, the course of action to be taken after obtaining the test result was stated in only 63 of 168 (37.5%) for a positive result and 43 of 168 (25.5%) for a negative result. Conclusions The quality of information posted on commercial websites marketing home tests online is unsatisfactory and potentially misleading for consumers. PMID:18263912

Diagnostic Accuracy of Global Pharma Health Fund Minilab™ in Assessing Pharmacopoeial Quality of Antimicrobials.

Science.gov (United States)

Pan, Hui; Ba-Thein, William

2018-01-01

Global Pharma Health Fund (GPHF) Minilab™, a semi-quantitative thin-layer chromatography (TLC)-based commercially available test kit, is widely used in drug quality surveillance globally, but its diagnostic accuracy is unclear. We investigated the diagnostic accuracy of Minilab system for antimicrobials, using high-performance liquid chromatography (HPLC) as reference standard. Following the Minilab protocols and the Pharmacopoeia of the People's Republic of China protocols, Minilab-TLC and HPLC were used to test five common antimicrobials (506 batches) for relative concentration of active pharmaceutical ingredients. The prevalence of poor-quality antimicrobials determined, respectively, by Minilab TLC and HPLC was amoxicillin (0% versus 14.9%), azithromycin (0% versus 17.4%), cefuroxime axetil (14.3% versus 0%), levofloxacin (0% versus 3.0%), and metronidazole (0% versus 38.0%). The Minilab TLC had false-positive and false-negative detection rates of 2.6% (13/506) and 15.2% (77/506) accordingly, resulting in the following test characteristics: sensitivity 0%, specificity 97.0%, positive predictive value 0, negative predictive value 0.8, positive likelihood ratio 0, negative likelihood ratio 1.0, diagnostic odds ratio 0, and adjusted diagnostic odds ratio 0.2. This study demonstrates unsatisfying diagnostic accuracy of Minilab system in screening poor-quality antimicrobials of common use. Using Minilab as a stand-alone system for monitoring drug quality should be reconsidered.

Task-oriented quality assessment and adaptation in real-time mission critical video streaming applications

Science.gov (United States)

Nightingale, James; Wang, Qi; Grecos, Christos

2015-02-01

In recent years video traffic has become the dominant application on the Internet with global year-on-year increases in video-oriented consumer services. Driven by improved bandwidth in both mobile and fixed networks, steadily reducing hardware costs and the development of new technologies, many existing and new classes of commercial and industrial video applications are now being upgraded or emerging. Some of the use cases for these applications include areas such as public and private security monitoring for loss prevention or intruder detection, industrial process monitoring and critical infrastructure monitoring. The use of video is becoming commonplace in defence, security, commercial, industrial, educational and health contexts. Towards optimal performances, the design or optimisation in each of these applications should be context aware and task oriented with the characteristics of the video stream (frame rate, spatial resolution, bandwidth etc.) chosen to match the use case requirements. For example, in the security domain, a task-oriented consideration may be that higher resolution video would be required to identify an intruder than to simply detect his presence. Whilst in the same case, contextual factors such as the requirement to transmit over a resource-limited wireless link, may impose constraints on the selection of optimum task-oriented parameters. This paper presents a novel, conceptually simple and easily implemented method of assessing video quality relative to its suitability for a particular task and dynamically adapting videos streams during transmission to ensure that the task can be successfully completed. Firstly we defined two principle classes of tasks: recognition tasks and event detection tasks. These task classes are further subdivided into a set of task-related profiles, each of which is associated with a set of taskoriented attributes (minimum spatial resolution, minimum frame rate etc.). For example, in the detection class

Dose and diagnostic image quality in digital tomosynthesis imaging of facial bones in pediatrics

Science.gov (United States)

King, J. M.; Hickling, S.; Elbakri, I. A.; Reed, M.; Wrogemann, J.

2011-03-01

The purpose of this study was to evaluate the use of digital tomosynthesis (DT) for pediatric facial bone imaging. We compared the eye lens dose and diagnostic image quality of DT facial bone exams relative to digital radiography (DR) and computed tomography (CT), and investigated whether we could modify our current DT imaging protocol to reduce patient dose while maintaining sufficient diagnostic image quality. We measured the dose to the eye lens for all three modalities using high-sensitivity thermoluminescent dosimeters (TLDs) and an anthropomorphic skull phantom. To assess the diagnostic image quality of DT compared to the corresponding DR and CT images, we performed an observer study where the visibility of anatomical structures in the DT phantom images were rated on a four-point scale. We then acquired DT images at lower doses and had radiologists indicate whether the visibility of each structure was adequate for diagnostic purposes. For typical facial bone exams, we measured eye lens doses of 0.1-0.4 mGy for DR, 0.3-3.7 mGy for DT, and 26 mGy for CT. In general, facial bone structures were visualized better with DT then DR, and the majority of structures were visualized well enough to avoid the need for CT. DT imaging provides high quality diagnostic images of the facial bones while delivering significantly lower doses to the lens of the eye compared to CT. In addition, we found that by adjusting the imaging parameters, the DT effective dose can be reduced by up to 50% while maintaining sufficient image quality.

Enabling 'Togetherness' in High-Quality Domestic Video Conferencing

NARCIS (Netherlands)

I. Kegel; P.S. Cesar Garcia (Pablo Santiago); A.J. Jansen (Jack); D.C.A. Bulterman (Dick); J. Kort; T. Stevens; N. Farber

2012-01-01

htmlabstractLow-cost video conferencing systems have provided an existence proof for the value of video communication in a home setting. At the same time, current systems have a number of fundamental limitations that inhibit more general social interactions among multiple groups of participants. In

Sound for digital video

CERN Document Server

Holman, Tomlinson

2013-01-01

Achieve professional quality sound on a limited budget! Harness all new, Hollywood style audio techniques to bring your independent film and video productions to the next level.In Sound for Digital Video, Second Edition industry experts Tomlinson Holman and Arthur Baum give you the tools and knowledge to apply recent advances in audio capture, video recording, editing workflow, and mixing to your own film or video with stunning results. This fresh edition is chockfull of techniques, tricks, and workflow secrets that you can apply to your own projects from preproduction

Subjective quality of video sequences rendered on LCD with local backlight dimming at different lighting conditions

DEFF Research Database (Denmark)

Mantel, Claire; Korhonen, Jari; Pedersen, Jesper Mørkhøj

2015-01-01

This paper focuses on the influence of ambient light on the perceived quality of videos displayed on Liquid Crystal Display (LCD) with local backlight dimming. A subjective test assessing the quality of videos with two backlight dimming methods and three lighting conditions, i.e. no light, low...... light level (5 lux) and higher light level (60 lux) was organized to collect subjective data. Results show that participants prefer the method exploiting local dimming possibilities to the conventional full backlight but that this preference varies depending on the ambient light level. The clear...... preference for one method at the low light conditions decreases at the high ambient light, confirming that the ambient light significantly attenuates the perception of the leakage defect (light leaking through dark pixels). Results are also highly dependent on the content of the sequence, which can modulate...

Enabling 'togetherness' in high-quality domestic video conferencing

NARCIS (Netherlands)

Kegel, I.; Cesar, P.; Jansen, J.; Bulterman, D.C.A.; Stevens, T.; Kort, J.; Färber, N.

2012-01-01

Low-cost video conferencing systems have provided an existence proof for the value of video communication in a home setting. At the same time, current systems have a number of fundamental limitations that inhibit more general social interactions among multiple groups of participants. In our work, we

Challenges in setting up quality control in diagnostic radiology ...

African Journals Online (AJOL)

Journal Home > Vol 24, No 4 (2015) >. Log in or ... Quality control (QC) on diagnostic radiology equipment form part of the fundamental requirements for the ... Inadequate cooperation by facilities management, lack of QC equipment and insufficient staff form the major challenges in setting up QC in the facilities under study.

Perception of quality control by personnel in diagnostic radiology ...

African Journals Online (AJOL)

This situation may be due to the perceived lack of interest and lack of cooperation from management of their facilities.The personnel also felt that they did not have sufficient training to implement QC and that QC results were difficult to analyse. Keywords: perception, quality control, personnel, management, diagnostic ...

Video enhancement : content classification and model selection

NARCIS (Netherlands)

Hu, H.

2010-01-01

The purpose of video enhancement is to improve the subjective picture quality. The field of video enhancement includes a broad category of research topics, such as removing noise in the video, highlighting some specified features and improving the appearance or visibility of the video content. The

Digital imaging in diagnostic radiology. Image quality - radiation exposure

International Nuclear Information System (INIS)

Schmidt, T.; Stieve, F.E.

1996-01-01

The publication contains the 37 lectures of the symposium on digital imaging in diagnostic radiology, held in November 1995 at Kloster Seeon, as well as contributions enhancing the information presented in the lectures. The publication reflects the state of the art in this subject field, discusses future trends and gives recommendations and information relating to current practice in radiology. In-depth information is given about R and D activities for the digitalisation of X-ray pictures and the image quality required to meet the purposes of modern diagnostics. Further aspects encompass radiological protection and dose optimization as well as optimization of examination methods. (vhe) [de

Current aspects in the development of the quality control in the conventional X-ray diagnostic radiology

International Nuclear Information System (INIS)

Stoeva, M.; Velkova, K.

2004-01-01

The role of the X-ray diagnostic radiology as one of the main factors forming the general public dose is indisputable. Following the requirement for justification of the application of X-rays for medical purposes, certain criteria for assessment of the parameters of the X-ray diagnostic equipment are formed and maximum permissible values defined. The latter are developed by the international and national radiation protection organizations and introduced both in the international and national legislation. The importance of the quality assurance concept for the radiation protection of the patient and staff in diagnostic radiology turned the quality control into main toll for obtaining high quality images with minimum dose to the patient and staff. X-ray diagnostics is one of the most common methods used in the medical practice. This is the main reason for the increase of the quality control protocols, winch makes their handling difficult. The latest developments in this area bring forward the idea for the development of specialized quality control software, which is capable of: 1) full or semi-automated calculation and assessment of the parameters of the X-ray diagnostic units; 2) tools for data handling and access; 3) tools for data analysis based on predefined procedures

NETWORK SERVICES FOR DIAGNOSTIC OPTODIGITAL COMPLEX FOR TELEMEDICINE

Directory of Open Access Journals (Sweden)

D. S. Kopylov

2014-03-01

Full Text Available The paper deals with a result of the network services development for the optodigital complex for telemedicine diagnostics. This complex is designed for laboratory and clinical tests in health care facilities. Composition of network services includes the following: a client application for database of diagnostic test, a web-service, a web interface, a video server and microimage processing server. Structure of these services makes it possible to combine set of software for transferring depersonalized medical data via the Internet and operating with optodigital devices included in the complex. Complex is consisted of three systems: micro-vision, endoscopic and network. The micro-vision system includes an automated digital microscope with two highly sensitive cameras which can be controlled remotely via the Internet. The endoscopic system gives the possibility to implement video broadcasting to remote users both during diagnostic tests and also off-line after tests. The network system is the core of the complex where network services and application software are functioning, intended for archiving, storage and providing access to the database of diagnostic tests. The following subjects are developed and tested for functional stability: states transfer protocol, commands transfer protocol and video-stream transfer protocol from automated digital microscope and video endoscope. These protocols can work in web browsers on modern mobile devices without additional software.

Standardized access, display, and retrieval of medical video

Science.gov (United States)

Bellaire, Gunter; Steines, Daniel; Graschew, Georgi; Thiel, Andreas; Bernarding, Johannes; Tolxdorff, Thomas; Schlag, Peter M.

1999-05-01

The system presented here enhances documentation and data- secured, second-opinion facilities by integrating video sequences into DICOM 3.0. We present an implementation for a medical video server extended by a DICOM interface. Security mechanisms conforming with DICOM are integrated to enable secure internet access. Digital video documents of diagnostic and therapeutic procedures should be examined regarding the clip length and size necessary for second opinion and manageable with today's hardware. Image sources relevant for this paper include 3D laparoscope, 3D surgical microscope, 3D open surgery camera, synthetic video, and monoscopic endoscopes, etc. The global DICOM video concept and three special workplaces of distinct applications are described. Additionally, an approach is presented to analyze the motion of the endoscopic camera for future automatic video-cutting. Digital stereoscopic video sequences are especially in demand for surgery . Therefore DSVS are also integrated into the DICOM video concept. Results are presented describing the suitability of stereoscopic display techniques for the operating room.

Head-camera video recordings of trauma core competency procedures can evaluate surgical resident's technical performance as well as colocated evaluators.

Science.gov (United States)

Mackenzie, Colin F; Pasley, Jason; Garofalo, Evan; Shackelford, Stacy; Chen, Hegang; Longinaker, Nyaradzo; Granite, Guinevere; Pugh, Kristy; Hagegeorge, George; Tisherman, Samuel A

2017-07-01

Unbiased evaluation of trauma core competency procedures is necessary to determine if residency and predeployment training courses are useful. We tested whether a previously validated individual procedure score (IPS) for individual procedure vascular exposure and fasciotomy (FAS) performance skills could discriminate training status by comparing IPS of evaluators colocated with surgeons to blind video evaluations. Performance of axillary artery (AA), brachial artery (BA), and femoral artery (FA) vascular exposures and lower extremity FAS on fresh cadavers by 40 PGY-2 to PGY-6 residents was video-recorded from head-mounted cameras. Two colocated trained evaluators assessed IPS before and after training. One surgeon in each pretraining tertile of IPS for each procedure was randomly identified for blind video review. The same 12 surgeons were video-recorded repeating the procedures less than 4 weeks after training. Five evaluators independently reviewed all 96 randomly arranged deidentified videos. Inter-rater reliability/consistency, intraclass correlation coefficients were compared by colocated versus video review of IPS, and errors. Study methodology and bias were judged by Medical Education Research Study Quality Instrument and the Quality Assessment of Diagnostic Accuracy Studies criteria. There were no differences (p ≥ 0.5) in IPS for AA, FA, FAS, whether evaluators were colocated or reviewed video recordings. Evaluator consistency was 0.29 (BA) - 0.77 (FA). Video and colocated evaluators were in total agreement (p = 1.0) for error recognition. Intraclass correlation coefficient was 0.73 to 0.92, dependent on procedure. Correlations video versus colocated evaluations were 0.5 to 0.9. Except for BA, blinded video evaluators discriminated (p competency. Prognostic study, level II.

Processing Decoded Video for LCD-LED Backlight Display

DEFF Research Database (Denmark)

Nadernejad, Ehsan

The quality of digital images and video signal on visual media such as TV screens and LCD displays is affected by two main factors; the display technology and compression standards. Accurate knowledge about the characteristics of display and the video signal can be utilized to develop advanced...... on local LED-LCD backlight. Second, removing the digital video codec artifacts such as blocking and ringing artifacts by post-processing algorithms. A novel algorithm based on image features with optimal balance between visual quality and power consumption was developed. In addition, to remove flickering...... algorithms for signal (image or video) enhancement. One particular application of such algorithms is the case of LCDs with dynamic local backlight. The thesis addressed two main problems; first, designing algorithms that improve the visual quality of perceived image and video and reduce power consumption...

Do Instructional Videos on Sputum Submission Result in Increased Tuberculosis Case Detection? A Randomized Controlled Trial.

Science.gov (United States)

Mhalu, Grace; Hella, Jerry; Doulla, Basra; Mhimbira, Francis; Mtutu, Hawa; Hiza, Helen; Sasamalo, Mohamed; Rutaihwa, Liliana; Rieder, Hans L; Seimon, Tamsyn; Mutayoba, Beatrice; Weiss, Mitchell G; Fenner, Lukas

2015-01-01

We examined the effect of an instructional video about the production of diagnostic sputum on case detection of tuberculosis (TB), and evaluated the acceptance of the video. Randomized controlled trial. We prepared a culturally adapted instructional video for sputum submission. We analyzed 200 presumptive TB cases coughing for more than two weeks who attended the outpatient department of the governmental Municipal Hospital in Mwananyamala (Dar es Salaam, Tanzania). They were randomly assigned to either receive instructions on sputum submission using the video before submission (intervention group, n = 100) or standard of care (control group, n = 100). Sputum samples were examined for volume, quality and presence of acid-fast bacilli by experienced laboratory technicians blinded to study groups. Median age was 39.1 years (interquartile range 37.0-50.0); 94 (47%) were females, 106 (53%) were males, and 49 (24.5%) were HIV-infected. We found that the instructional video intervention was associated with detection of a higher proportion of microscopically confirmed cases (56%, 95% confidence interval [95% CI] 45.7-65.9%, sputum smear positive patients in the intervention group versus 23%, 95% CI 15.2-32.5%, in the control group, p sex, modified the effectiveness of the intervention by improving it positively. When asked how well the video instructions were understood, the majority of patients in the intervention group reported to have understood the video instructions well (97%). Most of the patients thought the video would be useful in the cultural setting of Tanzania (92%). Sputum submission instructional videos increased the yield of tuberculosis cases through better quality of sputum samples. If confirmed in larger studies, instructional videos may have a substantial effect on the case yield using sputum microscopy and also molecular tests. This low-cost strategy should be considered as part of the efforts to control TB in resource-limited settings. Pan African

Quality control in dental diagnostic radiology : anomalous in the use of radiological equipment

International Nuclear Information System (INIS)

Alcaraz, M.; Martinez-Beneyto, Y.; Jodar, S.; Velasco, E.; Garcia-Vera, M. C.

2004-01-01

7,176 official quality control reports on dental diagnostic radiology were studied, relating to dental clinics located in 37 Spanish provinces covering 16 different autonomous Regions. The reports were issued as a result of the entry into force of Royal Decree 2071/1995 on quality control in General Diagnostic Radiology facilities, this Royal Decree was replaced by R. D. 1976/1999. The reports were writen by the UTPR (Technical Unit of Radiological Protection) Agsigma S. A. L., a company approved by the Nuclear Safety Council, and they correspond with the official reports issued during 1996-2001. This meants that a 5-year period has been monitored in order to observe the impacts of the establlishment of this legislation on quality control in intraoral dental diagnostic radiology facilities. The results show that 72.79% of the reports checked in 2001 would comply with the European Union's official recommendation (70 kVp, 8 mA> 1.5 mm of Al and 20 cm collimator length). Significant alterations have detected in a third (30.59%) of the radiological equipment. (Author) 36 refs

Staff acceptance of video monitoring for coordination: a video system to support perioperative situation awareness.

Science.gov (United States)

Kim, Young Ju; Xiao, Yan; Hu, Peter; Dutton, Richard

2009-08-01

To understand staff acceptance of a remote video monitoring system for operating room (OR) coordination. Improved real-time remote visual access to OR may enhance situational awareness but also raises privacy concerns for patients and staff. Survey. A system was implemented in a six-room surgical suite to display OR monitoring video at an access restricted control desk area. Image quality was manipulated to improve staff acceptance. Two months after installation, interviews and a survey were conducted on staff acceptance of video monitoring. About half of all OR personnel responded (n = 63). Overall levels of concerns were low, with 53% rated no concerns and 42% little concern. Top two reported uses of the video were to see if cases are finished and to see if a room is ready. Viewing the video monitoring system as useful did not reduce levels of concern. Staff in supervisory positions perceived less concern about the system's impact on privacy than did those supervised (p < 0.03). Concerns for patient privacy correlated with concerns for staff privacy and performance monitoring. Technical means such as manipulating image quality helped staff acceptance. Manipulation of image quality resulted overall acceptance of monitoring video, with residual levels of concerns. OR nurses may express staff privacy concern in the form of concerns over patient privacy. This study provided suggestions for technological and implementation strategies of video monitoring for coordination use in OR. Deployment of communication technology and integration of clinical information will likely raise concerns over staff privacy and performance monitoring. The potential gain of increased information access may be offset by negative impact of a sense of loss of autonomy.

A No-Reference Modular Video Quality Prediction Model for H.265/HEVC and VP9 Codecs on a Mobile Device

Directory of Open Access Journals (Sweden)

Debajyoti Pal

2017-01-01

Full Text Available We propose a modular no-reference video quality prediction model for videos that are encoded with H.265/HEVC and VP9 codecs and viewed on mobile devices. The impairments which can affect video transmission are classified into two broad types depending upon which layer of the TCP/IP model they originated from. Impairments from the network layer are called the network QoS factors, while those from the application layer are called the application/payload QoS factors. Initially we treat the network and application QoS factors separately and find out the 1 : 1 relationship between the respective QoS factors and the corresponding perceived video quality or QoE. The mapping from the QoS to the QoE domain is based upon a decision variable that gives an optimal performance. Next, across each group we choose multiple QoS factors and find out the QoE for such multifactor impaired videos by using an additive, multiplicative, and regressive approach. We refer to these as the integrated network and application QoE, respectively. At the end, we use a multiple regression approach to combine the network and application QoE for building the final model. We also use an Artificial Neural Network approach for building the model and compare its performance with the regressive approach.

Dimensioning Method for Conversational Video Applications in Wireless Convergent Networks

Directory of Open Access Journals (Sweden)

Raquel Perez Leal

2007-12-01

Full Text Available New convergent services are becoming possible, thanks to the expansion of IP networks based on the availability of innovative advanced coding formats such as H.264, which reduce network bandwidth requirements providing good video quality, and the rapid growth in the supply of dual-mode WiFi cellular terminals. This paper provides, first, a comprehensive subject overview as several technologies are involved, such as medium access protocol in IEEE802.11, H.264 advanced video coding standards, and conversational application characterization and recommendations. Second, the paper presents a new and simple dimensioning model of conversational video over wireless LAN. WLAN is addressed under the optimal network throughput and the perspective of video quality. The maximum number of simultaneous users resulting from throughput is limited by the collisions taking place in the shared medium with the statistical contention protocol. The video quality is conditioned by the packet loss in the contention protocol. Both approaches are analyzed within the scope of the advanced video codecs used in conversational video over IP, to conclude that conversational video dimensioning based on network throughput is not enough to ensure a satisfactory user experience, and video quality has to be taken also into account. Finally, the proposed model has been applied to a real-office scenario.

Dimensioning Method for Conversational Video Applications in Wireless Convergent Networks

Directory of Open Access Journals (Sweden)

Alonso JoséI

2008-01-01

Full Text Available Abstract New convergent services are becoming possible, thanks to the expansion of IP networks based on the availability of innovative advanced coding formats such as H.264, which reduce network bandwidth requirements providing good video quality, and the rapid growth in the supply of dual-mode WiFi cellular terminals. This paper provides, first, a comprehensive subject overview as several technologies are involved, such as medium access protocol in IEEE802.11, H.264 advanced video coding standards, and conversational application characterization and recommendations. Second, the paper presents a new and simple dimensioning model of conversational video over wireless LAN. WLAN is addressed under the optimal network throughput and the perspective of video quality. The maximum number of simultaneous users resulting from throughput is limited by the collisions taking place in the shared medium with the statistical contention protocol. The video quality is conditioned by the packet loss in the contention protocol. Both approaches are analyzed within the scope of the advanced video codecs used in conversational video over IP, to conclude that conversational video dimensioning based on network throughput is not enough to ensure a satisfactory user experience, and video quality has to be taken also into account. Finally, the proposed model has been applied to a real-office scenario.

Quality control test solutions for diagnostic radiology, nuclear medicine and health physics with PTW equipment

International Nuclear Information System (INIS)

Froescher, Olga

2007-01-01

Complete test of publication follows. In 1922 PTW-Freiburg was founded to produce and market a revolutionary new electromechanical component for measuring very small electrical charges. Today PTW is the specialist and one of the global market leaders for manufacturing and supplying high-quality products in diagnostic radiology, nuclear medicine, radiation therapy and health physics. The quality control of X-ray images is influenced by a number of parameters. To maintain a consistent performance of X-ray installations, quality checks have to be conducted regularly. PTW offers a variety of diagnostic test tools for different X-ray devices, and therefore to reduce patient exposure and costs for X-ray departments. PTW's 'Code of Practice' defines in an easy and compact way how to perform quality control measurements on different diagnostic X-ray installations. The necessary equipment for measuring main parameters as well as acceptable limits are mentioned accordingly. The 'Code of Practice' bases on actual standards.

High efficiency video coding (HEVC) algorithms and architectures

CERN Document Server

Budagavi, Madhukar; Sullivan, Gary

2014-01-01

This book provides developers, engineers, researchers and students with detailed knowledge about the High Efficiency Video Coding (HEVC) standard. HEVC is the successor to the widely successful H.264/AVC video compression standard, and it provides around twice as much compression as H.264/AVC for the same level of quality. The applications for HEVC will not only cover the space of the well-known current uses and capabilities of digital video – they will also include the deployment of new services and the delivery of enhanced video quality, such as ultra-high-definition television (UHDTV) and video with higher dynamic range, wider range of representable color, and greater representation precision than what is typically found today. HEVC is the next major generation of video coding design – a flexible, reliable and robust solution that will support the next decade of video applications and ease the burden of video on world-wide network traffic. This book provides a detailed explanation of the various parts ...

Efficient Delivery of Scalable Video Using a Streaming Class Model

Directory of Open Access Journals (Sweden)

Jason J. Quinlan

2018-03-01

Full Text Available When we couple the rise in video streaming with the growing number of portable devices (smart phones, tablets, laptops, we see an ever-increasing demand for high-definition video online while on the move. Wireless networks are inherently characterised by restricted shared bandwidth and relatively high error loss rates, thus presenting a challenge for the efficient delivery of high quality video. Additionally, mobile devices can support/demand a range of video resolutions and qualities. This demand for mobile streaming highlights the need for adaptive video streaming schemes that can adjust to available bandwidth and heterogeneity, and can provide a graceful changes in video quality, all while respecting viewing satisfaction. In this context, the use of well-known scalable/layered media streaming techniques, commonly known as scalable video coding (SVC, is an attractive solution. SVC encodes a number of video quality levels within a single media stream. This has been shown to be an especially effective and efficient solution, but it fares badly in the presence of datagram losses. While multiple description coding (MDC can reduce the effects of packet loss on scalable video delivery, the increased delivery cost is counterproductive for constrained networks. This situation is accentuated in cases where only the lower quality level is required. In this paper, we assess these issues and propose a new approach called Streaming Classes (SC through which we can define a key set of quality levels, each of which can be delivered in a self-contained manner. This facilitates efficient delivery, yielding reduced transmission byte-cost for devices requiring lower quality, relative to MDC and Adaptive Layer Distribution (ALD (42% and 76% respective reduction for layer 2, while also maintaining high levels of consistent quality. We also illustrate how selective packetisation technique can further reduce the effects of packet loss on viewable quality by

Video medical interpretation over 3G cellular networks: a feasibility study.

Science.gov (United States)

Locatis, Craig; Williamson, Deborah; Sterrett, James; Detzler, Isabel; Ackerman, Michael

2011-12-01

To test the feasibility of using cell phone technology to provide video medical interpretation services at a distance. Alternative cell phone services were researched and videoconferencing technologies were tried out to identify video products and telecommunication services needed to meet video medical interpretation requirements. The video and telecommunication technologies were tried out in a pharmacy setting and compared with use of the telephone. Outcomes were similar to findings in previous research involving video medical interpretation with higher bandwidth and video quality. Patients appreciated the interpretation service no matter how it is provided, while health providers and interpreters preferred video. It is possible to provide video medical interpretation services via cellular communication using lower bandwidth videoconferencing technology that provides sufficient quality, at least in pharmacy settings. However, a number of issues need to be addressed to ensure quality of service.

Modeling the Subjective Quality of Highly Contrasted Videos Displayed on LCD With Local Backlight Dimming

DEFF Research Database (Denmark)

Mantel, Claire; Bech, Søren; Korhonen, Jari

2015-01-01

Local backlight dimming is a technology aiming at both saving energy and improving visual quality on television sets. As the rendition of the image is specified locally, the numerical signal corresponding to the displayed image needs to be computed through a model of the display. This simulated...... signal can then be used as input to objective quality metrics. The focus of this paper is on determining which characteristics of locally backlit displays influence quality assessment. A subjective experiment assessing the quality of highly contrasted videos displayed with various local backlight......-dimming algorithms is set up. Subjective results are then compared with both objective measures and objective quality metrics using different display models. The first analysis indicates that the most significant objective features are temporal variations, power consumption (probably representing leakage...

Segment scheduling method for reducing 360° video streaming latency

Science.gov (United States)

Gudumasu, Srinivas; Asbun, Eduardo; He, Yong; Ye, Yan

2017-09-01

360° video is an emerging new format in the media industry enabled by the growing availability of virtual reality devices. It provides the viewer a new sense of presence and immersion. Compared to conventional rectilinear video (2D or 3D), 360° video poses a new and difficult set of engineering challenges on video processing and delivery. Enabling comfortable and immersive user experience requires very high video quality and very low latency, while the large video file size poses a challenge to delivering 360° video in a quality manner at scale. Conventionally, 360° video represented in equirectangular or other projection formats can be encoded as a single standards-compliant bitstream using existing video codecs such as H.264/AVC or H.265/HEVC. Such method usually needs very high bandwidth to provide an immersive user experience. While at the client side, much of such high bandwidth and the computational power used to decode the video are wasted because the user only watches a small portion (i.e., viewport) of the entire picture. Viewport dependent 360°video processing and delivery approaches spend more bandwidth on the viewport than on non-viewports and are therefore able to reduce the overall transmission bandwidth. This paper proposes a dual buffer segment scheduling algorithm for viewport adaptive streaming methods to reduce latency when switching between high quality viewports in 360° video streaming. The approach decouples the scheduling of viewport segments and non-viewport segments to ensure the viewport segment requested matches the latest user head orientation. A base layer buffer stores all lower quality segments, and a viewport buffer stores high quality viewport segments corresponding to the most recent viewer's head orientation. The scheduling scheme determines viewport requesting time based on the buffer status and the head orientation. This paper also discusses how to deploy the proposed scheduling design for various viewport adaptive video

High Dynamic Range Video

CERN Document Server

Myszkowski, Karol

2008-01-01

This book presents a complete pipeline forHDR image and video processing fromacquisition, through compression and quality evaluation, to display. At the HDR image and video acquisition stage specialized HDR sensors or multi-exposure techniques suitable for traditional cameras are discussed. Then, we present a practical solution for pixel values calibration in terms of photometric or radiometric quantities, which are required in some technically oriented applications. Also, we cover the problem of efficient image and video compression and encoding either for storage or transmission purposes, in

Learning a Continuous-Time Streaming Video QoE Model.

Science.gov (United States)

Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C

2018-05-01

Over-the-top adaptive video streaming services are frequently impacted by fluctuating network conditions that can lead to rebuffering events (stalling events) and sudden bitrate changes. These events visually impact video consumers' quality of experience (QoE) and can lead to consumer churn. The development of models that can accurately predict viewers' instantaneous subjective QoE under such volatile network conditions could potentially enable the more efficient design of quality-control protocols for media-driven services, such as YouTube, Amazon, Netflix, and so on. However, most existing models only predict a single overall QoE score on a given video and are based on simple global video features, without accounting for relevant aspects of human perception and behavior. We have created a QoE evaluator, called the time-varying QoE Indexer, that accounts for interactions between stalling events, analyzes the spatial and temporal content of a video, predicts the perceptual video quality, models the state of the client-side data buffer, and consequently predicts continuous-time quality scores that agree quite well with human opinion scores. The new QoE predictor also embeds the impact of relevant human cognitive factors, such as memory and recency, and their complex interactions with the video content being viewed. We evaluated the proposed model on three different video databases and attained standout QoE prediction performance.

Layer-based buffer aware rate adaptation design for SHVC video streaming

Science.gov (United States)

Gudumasu, Srinivas; Hamza, Ahmed; Asbun, Eduardo; He, Yong; Ye, Yan

2016-09-01

This paper proposes a layer based buffer aware rate adaptation design which is able to avoid abrupt video quality fluctuation, reduce re-buffering latency and improve bandwidth utilization when compared to a conventional simulcast based adaptive streaming system. The proposed adaptation design schedules DASH segment requests based on the estimated bandwidth, dependencies among video layers and layer buffer fullness. Scalable HEVC video coding is the latest state-of-art video coding technique that can alleviate various issues caused by simulcast based adaptive video streaming. With scalable coded video streams, the video is encoded once into a number of layers representing different qualities and/or resolutions: a base layer (BL) and one or more enhancement layers (EL), each incrementally enhancing the quality of the lower layers. Such layer based coding structure allows fine granularity rate adaptation for the video streaming applications. Two video streaming use cases are presented in this paper. The first use case is to stream HD SHVC video over a wireless network where available bandwidth varies, and the performance comparison between proposed layer-based streaming approach and conventional simulcast streaming approach is provided. The second use case is to stream 4K/UHD SHVC video over a hybrid access network that consists of a 5G millimeter wave high-speed wireless link and a conventional wired or WiFi network. The simulation results verify that the proposed layer based rate adaptation approach is able to utilize the bandwidth more efficiently. As a result, a more consistent viewing experience with higher quality video content and minimal video quality fluctuations can be presented to the user.

Application of Quality Assurance Strategies in Diagnostics and Clinical Support Services in Iranian Hospitals

NARCIS (Netherlands)

Aghaei Hashjin, Asgar; Kringos, Dionne; Ravaghi, Hamid; Manoochehri, Jila; Gorji, Hassan Abolghasem; Klazinga, Niek S.

2015-01-01

Background: Iran has a widespread diagnostics and clinical support services (DCSS) network that plays a crucial role in providing diagnostic and clinical support services to both inpatient and outpatient care. However, very little is known on the application of quality assurance (QA) policies in

Patient dosimetry and image quality in conventional diagnostic radiology. An experience from a local Serbian hospital

International Nuclear Information System (INIS)

Olivera Ciraj-Bjelac; Milojko Kovacevic; Dusko Kosutic; Milan Loncar; Dajana Veljkovic

2007-01-01

Complete test of publication follows. The optimization of image quality vs. patient dose ins an important task in medical imaging. Maximal validity of optimization has to be based on clinical images. Simultaneous measurement of patient dose levels and image quality assessment is used to investigate possibilities for dose reduction and maintain image quality. The survey was conducted in a local hospital performing more than 60000 images annually and representing typical Serbian practice. For four most frequent diagnostic procedures (seven projections) patient exposure was measured using kerma area product meter. Image quality was assessed by experienced radiologists using 'European Guidelines on Quality Criteria for Diagnostic Radiographic Images'. Following examination types were included into the survey: chest PA, chest LAT, pelvis AP, lumbar spine AP, lumbar spine LAT and LSJ, skull PA and skull LAT. Comparing actual radiographic technique with recommended technique in European Guidelines, modification of practice was proposed and implemented and image quality was re-assessed. At least 10 adult patients were followed for each projection, before and after corrective actions. Large dose saving without compromising diagnostic information were found for some examination types, showing that this simple method is very efficient dose reduction tool in conventional diagnostic radiology. Also, need for staff training and difficulties related to practical implementation of optimization methods in Serbia were discussed.

Performance Analysis of Video Transmission Using Sequential Distortion Minimization Method for Digital Video Broadcasting Terrestrial

Directory of Open Access Journals (Sweden)

Novita Astin

2016-12-01

Full Text Available This paper presents about the transmission of Digital Video Broadcasting system with streaming video resolution 640x480 on different IQ rate and modulation. In the video transmission, distortion often occurs, so the received video has bad quality. Key frames selection algorithm is flexibel on a change of video, but on these methods, the temporal information of a video sequence is omitted. To minimize distortion between the original video and received video, we aimed at adding methodology using sequential distortion minimization algorithm. Its aim was to create a new video, better than original video without significant loss of content between the original video and received video, fixed sequentially. The reliability of video transmission was observed based on a constellation diagram, with the best result on IQ rate 2 Mhz and modulation 8 QAM. The best video transmission was also investigated using SEDIM (Sequential Distortion Minimization Method and without SEDIM. The experimental result showed that the PSNR (Peak Signal to Noise Ratio average of video transmission using SEDIM was an increase from 19,855 dB to 48,386 dB and SSIM (Structural Similarity average increase 10,49%. The experimental results and comparison of proposed method obtained a good performance. USRP board was used as RF front-end on 2,2 GHz.

Development of Tandem ionization chambers for use in quality control programs in radiotherapy and diagnostic radiology

International Nuclear Information System (INIS)

Costa, Alessandro Martins da

2003-01-01

A quality control program of X-ray equipment used in diagnostic radiology and radiotherapy requires the check of the beam qualities constancy in terms of the half-value layers. In this work, two special double-faced parallel-plate ionization chambers were developed with inner electrodes of different materials, in tandem system. The different energy response of the two faces of each chamber allowed the development of tandem systems useful for the check of beam qualities constancy. The main application of these ionization chambers will be in quality control programs of diagnostic and therapeutic X-ray equipment for confirmation of half-value layers previously determined by the conventional method. Moreover, the tandem chambers may also be utilized for measurements of air kerma values (and air kerma rates) in kilo voltage X-radiation fields used for diagnostic and therapeutic procedures. The chambers were studied in relation to their operational characteristics, and they were calibrated in X-ray beams in accordance to international recommendations. They presented a very good level of performance. In this developed system no absorbers or special set-ups are necessary. A methodology of use of the chambers in the quality control of diagnostic and therapeutic X-ray systems was established, with the elaboration of the respective procedures. (author)

Distributed video coding with multiple side information

DEFF Research Database (Denmark)

Huang, Xin; Brites, C.; Ascenso, J.

2009-01-01

Distributed Video Coding (DVC) is a new video coding paradigm which mainly exploits the source statistics at the decoder based on the availability of some decoder side information. The quality of the side information has a major impact on the DVC rate-distortion (RD) performance in the same way...... the quality of the predictions had a major impact in predictive video coding. In this paper, a DVC solution exploiting multiple side information is proposed; the multiple side information is generated by frame interpolation and frame extrapolation targeting to improve the side information of a single...

Establishment of standard x-ray qualities to be used in diagnostic level at SSDLs

International Nuclear Information System (INIS)

A-Aziz, R.O.

2007-08-01

The objective of the present work is to modify x-ray machine (used by the secondary standard dosimetry laboratory in Sudan) to produce x-ray qualities suitable for the calibration at diagnostic level. It based on experimental evaluations. The importance of this study appears in development of protocols to calibrate the instruments used in diagnostic radiology in by good response of the instruments and low cost. In particular, the half value layer (HVL) values for the following qualities 40, 60, 80, 100, 120 and 150 were determined using various attenuation layers. Ionization chamber was used to determine the free air kerma rate at a distance of 100 cm from the x-ray generator. The obtained HVL values were compared with standard values of diagnostic levels. It was observed that the HVL of the present x-ray machine in most qualities are smaller than the standard ones. An approved method (described in the standard IEC 61267) was applied to determine the amount of additional filtration required to meet the standard values. The results show that the available cupper layers were not suitable for this purpose as most of the x-ray was absorbed in the material. Aluminum layers, on the other hand , show good performances to reduce the beams to the desired levels. The amount of additional filtration (from aluminum layers) needed in order to establish standard x-ray qualities to be used in diagnostic level were determined.(Author)

Summarization of Surveillance Video Sequences Using Face Quality Assessment

DEFF Research Database (Denmark)

Nasrollahi, Kamal; Moeslund, Thomas B.; Rahmati, Mohammad

2011-01-01

Constant working surveillance cameras in public places, such as airports and banks, produce huge amount of video data. Faces in such videos can be extracted in real time. However, most of these detected faces are either redundant or useless. Redundant information adds computational costs to facial...

Misinformation is prevalent in psoriasis-related YouTube videos.

Science.gov (United States)

Qi, J; Trang, T; Doong, J; Kang, S; Chien, A L

2016-11-15

Background Psoriasis patients seek information online, but little is known about their interaction with YouTube. We examined the quality of content in psoriasis-related YouTube videos and investigated their interactions with viewers.Methods YouTube was searched using the term "psoriasis." Relevant videos in English were independently categorized by two reviewers as useful, misleading, or patient view (regarding experience with psoriasis). Disagreements were settled by a third reviewer. Videos were rated on a Global Quality Scale (GQS) (1=poor, 5=excellent).Results According to our reviewers, 17% of the 47 videos were useful, 21% were misleading, and 62% represented patient views. Mean GQS scores were 4.2 ± 1.3 for useful videos, 1.7 ± 0.7 for misleading videos, and 2.2 ± 1.1 for patient view videos (p<0.001). Video views per day did not differ among the categories (p=0.65), whereas useful videos had fewest "Likes" (useful: 31 ± 55, 33 misleading: 151 ± 218, patient views: 165 ± 325, p=0.06) and comments (useful: 9.8 ± 18.3, misleading: 64.1 ± 89.7, 124.9 ± 34 199.4, p=0.009).Conclusions Useful videos were highest in quality but had similar viewership as misleading and patient view videos, with lower popularity and  engagement of users compared to other categories. Physicians and psoriasis patients should be aware of this pattern when pproaching YouTube as a resource.

Statistical conditional sampling for variable-resolution video compression.

Directory of Open Access Journals (Sweden)

Alexander Wong

Full Text Available In this study, we investigate a variable-resolution approach to video compression based on Conditional Random Field and statistical conditional sampling in order to further improve compression rate while maintaining high-quality video. In the proposed approach, representative key-frames within a video shot are identified and stored at full resolution. The remaining frames within the video shot are stored and compressed at a reduced resolution. At the decompression stage, a region-based dictionary is constructed from the key-frames and used to restore the reduced resolution frames to the original resolution via statistical conditional sampling. The sampling approach is based on the conditional probability of the CRF modeling by use of the constructed dictionary. Experimental results show that the proposed variable-resolution approach via statistical conditional sampling has potential for improving compression rates when compared to compressing the video at full resolution, while achieving higher video quality when compared to compressing the video at reduced resolution.

Real-time video streaming system for LHD experiment using IP multicast

International Nuclear Information System (INIS)

Emoto, Masahiko; Yamamoto, Takashi; Yoshida, Masanobu; Nagayama, Yoshio; Hasegawa, Makoto

2009-01-01

In order to accomplish smooth cooperation research, remote participation plays an important role. For this purpose, the authors have been developing various applications for remote participation for the LHD (Large Helical Device) experiments, such as Web interface for visualization of acquired data. The video streaming system is one of them. It is useful to grasp the status of the ongoing experiment remotely, and we provide the video images displayed in the control room to the remote users. However, usual streaming servers cannot send video images without delay. The delay changes depending on how to send the images, but even a little delay might become critical if the researchers use the images to adjust the diagnostic devices. One of the main causes of delay is the procedure of compressing and decompressing the images. Furthermore, commonly used video compression method is lossy; it removes less important information to reduce the size. However, lossy images cannot be used for physical analysis because the original information is lost. Therefore, video images for remote participation should be sent without compression in order to minimize the delay and to supply high quality images durable for physical analysis. However, sending uncompressed video images requires large network bandwidth. For example, sending 5 frames of 16bit color SXGA images a second requires 100Mbps. Furthermore, the video images must be sent to several remote sites simultaneously. It is hard for a server PC to handle such a large data. To cope with this problem, the authors adopted IP multicast to send video images to several remote sites at once. Because IP multicast packets are sent only to the network on which the clients want the data; the load of the server does not depend on the number of clients and the network load is reduced. In this paper, the authors discuss the feasibility of high bandwidth video streaming system using IP multicast. (author)

Identifying Measures Used for Assessing Quality of YouTube Videos with Patient Health Information: A Review of Current Literature.

Science.gov (United States)

Gabarron, Elia; Fernandez-Luque, Luis; Armayones, Manuel; Lau, Annie Ys

2013-02-28

Recent publications on YouTube have advocated its potential for patient education. However, a reliable description of what could be considered quality information for patient education on YouTube is missing. To identify topics associated with the concept of quality information for patient education on YouTube in the scientific literature. A literature review was performed in MEDLINE, ISI Web of Knowledge, Scopus, and PsychINFO. Abstract selection was first conducted by two independent reviewers; discrepancies were discussed in a second abstract review with two additional independent reviewers. Full text of selected papers were analyzed looking for concepts, definitions, and topics used by its authors that focused on the quality of information on YouTube for patient education. In total, 456 abstracts were extracted and 13 papers meeting eligibility criteria were analyzed. Concepts identified related to quality of information for patient education are categorized as expert-driven, popularity-driven, or heuristic-driven measures. These include (in descending order): (1) quality of content in 10/13 (77%), (2) view count in 9/13 (69%), (3) health professional opinion in 8/13 (62%), (4) adequate length or duration in 6/13 (46%), (5) public ratings in 5/13 (39%), (6) adequate title, tags, and description in 5/13 (39%), (7) good description or a comprehensive narrative in 4/13 (31%), (8) evidence-based practices included in video in 4/13 (31%), (9) suitability as a teaching tool in 4/13 (31%), (10) technical quality in 4/13 (31%), (11) credentials provided in video in 4/13 (31%), (12) enough amount of content to identify its objective in 3/13 (23%), and (13) viewership share in 2/13 (15%). Our review confirms that the current topics linked to quality of information for patient education on YouTube are unclear and not standardized. Although expert-driven, popularity-driven, or heuristic-driven measures are used as proxies to estimate the quality of video information

Guidelines for Quality Control of Equipment Used in Diagnostic Radiology in the Netherlands

International Nuclear Information System (INIS)

Berg, L. van den; Aarts, C.N.M.; Beentjes, L.B.; Dalen, A. van; Elsakkers, P.; Julius, H.W.; Kicken, P.J.H.; Meer, F. van der; Teeuwisse, W.; Thijssen, M.A.O.; Zoetelief, J.

1998-01-01

The Dutch working group on 'Quality Criteria for Equipment Used in Diagnostic Radiology' has formulated guidelines providing technical criteria for equipment used in conventional diagnostic radiology. These guidelines are applicable to the technical parameters having a major impact on image quality and patient dose and include methods for testing. The following parameters are included: tube voltage, automatic exposure control, film processing, film-screen combination, light tightness and illumination of the dark room, half-value layer and filtration, light field, grid, focal spot size, viewing boxes and geometrical indicators. Each guideline consists of the following chapters: (1) Scope and field of application, (2) Background information, (3) Test procedure, (4) Test frequency, (5) Registration of observations, (6) Evaluation and interpretation, (7) Test report. Chapter 3 includes both the principles of the test method and a step by step description of the procedures. The principles of the test procedure provide a basis for adaptation to local circumstances. The step by step test procedure allows a quality control measurement to be performed with limited physical knowledge of the equipment. Chapter 6 includes limiting values. Draft guidelines were evaluated in practice in 20 hospitals. The final document has been accepted by the professional societies in the Netherlands and the Dutch Minister of Health as a reference set of tools to perform Quality Control of equipment used for conventional diagnostic radiology. (author)

Enhance Video Film using Retnix method

Science.gov (United States)

Awad, Rasha; Al-Zuky, Ali A.; Al-Saleh, Anwar H.; Mohamad, Haidar J.

2018-05-01

An enhancement technique used to improve the studied video quality. Algorithms like mean and standard deviation are used as a criterion within this paper, and it applied for each video clip that divided into 80 images. The studied filming environment has different light intensity (315, 566, and 644Lux). This different environment gives similar reality to the outdoor filming. The outputs of the suggested algorithm are compared with the results before applying it. This method is applied into two ways: first, it is applied for the full video clip to get the enhanced film; second, it is applied for every individual image to get the enhanced image then compiler them to get the enhanced film. This paper shows that the enhancement technique gives good quality video film depending on a statistical method, and it is recommended to use it in different application.

Visual signal quality assessment quality of experience (QOE)

CERN Document Server

Ma, Lin; Lin, Weisi; Ngan, King

2015-01-01

This book provides comprehensive coverage of the latest trends/advances in subjective and objective quality evaluation for traditional visual signals, such as 2D images and video, as well as the most recent challenges for the field of multimedia quality assessment and processing, such as mobile video and social media. Readers will learn how to ensure the highest storage/delivery/ transmission quality of visual content (including image, video, graphics, animation, etc.) from the server to the consumer, under resource constraints, such as computation, bandwidth, storage space, battery life, etc.    Provides an overview of quality assessment for traditional visual signals; Covers newly emerged visual signals such as social media, 3D image/video, mobile video, high dynamic range (HDR) images, graphics/animation, etc., which demand better quality of experience (QoE); Helps readers to develop better quality metrics and processing methods for newly emerged visual signals; Enables testing, optimizing, benchmarking...

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Cerataphis brasiliensis

Science.gov (United States)

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the palm aphid, Cerataphis brasiliensis, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures...

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Aphis gossypii

Science.gov (United States)

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the cotton aphid, Aphis gossypii, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures that ca...

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Myzus persicae

Science.gov (United States)

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the green peach aphid, Myzus persicae, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures t...

A Super-resolution Reconstruction Algorithm for Surveillance Video

Directory of Open Access Journals (Sweden)

Jian Shao

2017-01-01

Full Text Available Recent technological developments have resulted in surveillance video becoming a primary method of preserving public security. Many city crimes are observed in surveillance video. The most abundant evidence collected by the police is also acquired through surveillance video sources. Surveillance video footage offers very strong support for solving criminal cases, therefore, creating an effective policy, and applying useful methods to the retrieval of additional evidence is becoming increasingly important. However, surveillance video has had its failings, namely, video footage being captured in low resolution (LR and bad visual quality. In this paper, we discuss the characteristics of surveillance video and describe the manual feature registration – maximum a posteriori – projection onto convex sets to develop a super-resolution reconstruction method, which improves the quality of surveillance video. From this method, we can make optimal use of information contained in the LR video image, but we can also control the image edge clearly as well as the convergence of the algorithm. Finally, we make a suggestion on how to adjust the algorithm adaptability by analyzing the prior information of target image.

Evaluation of video capture equipment for secondary image acquisition in the PACS.

Science.gov (United States)

Sukenobu, Yoshiharu; Sasagaki, Michihiro; Hirabuki, Norio; Naito, Hiroaki; Narumi, Yoshifumi; Inamura, Kiyonari

2002-01-01

There are many cases in which picture archiving and communication systems (PACS) are built with old-type existing modalities with no DICOM output. One of the methods for interfacing them to the PACS is to implement video capture (/ frame grabber) equipment. This equipment takes analog video signal output from medical imaging modalities, and amplitude of the video signal is A/D converted and supplied to the PACS. In this report, we measured and evaluated the accuracy at which this video capture equipment could capture the image. From the physical evaluation, we found the pixel values of an original image and its captured image were almost equal in gray level from 20%-90%. The change in the pixel values of a captured image was +/-3 on average. The change of gray level concentration was acceptable and had an average standard deviation of around 0.63. As for resolution, the degradation was observed at the highest physical level. In a subjective evaluation, the evaluation value of the CT image had a grade of 2.81 on the average (the same quality for a reference image was set to a grade of 3.0). Abnormalities in heads, chests, and abdomens were judged not to influence diagnostic accuracy. Some small differences were seen when comparing captured and reference images, but they are recognized as having no influence on the diagnoses.

Subjective quality of videos displayed with local backlight dimming at different peak white and ambient light levels

DEFF Research Database (Denmark)

Mantel, Claire; Korhonen, Jari; Forchhammer, Søren

2015-01-01

In this paper the influence of ambient light and peak white (maximum brightness) of a display on the subjective quality of videos shown with local backlight dimming is examined. A subjective experiment investigating those factors is set-up using high contrast test sequences. The results are firstly...

Deep video deblurring

KAUST Repository

Su, Shuochen

2016-11-25

Motion blur from camera shake is a major problem in videos captured by hand-held devices. Unlike single-image deblurring, video-based approaches can take advantage of the abundant information that exists across neighboring frames. As a result the best performing methods rely on aligning nearby frames. However, aligning images is a computationally expensive and fragile procedure, and methods that aggregate information must therefore be able to identify which regions have been accurately aligned and which have not, a task which requires high level scene understanding. In this work, we introduce a deep learning solution to video deblurring, where a CNN is trained end-to-end to learn how to accumulate information across frames. To train this network, we collected a dataset of real videos recorded with a high framerate camera, which we use to generate synthetic motion blur for supervision. We show that the features learned from this dataset extend to deblurring motion blur that arises due to camera shake in a wide range of videos, and compare the quality of results to a number of other baselines.

Resource-Constrained Low-Complexity Video Coding for Wireless Transmission

DEFF Research Database (Denmark)

Ukhanova, Ann

of video quality. We proposed a new metric for objective quality assessment that considers frame rate. As many applications deal with wireless video transmission, we performed an analysis of compression and transmission systems with a focus on power-distortion trade-off. We proposed an approach...... for ratedistortion-complexity optimization of upcoming video compression standard HEVC. We also provided a new method allowing decrease of power consumption on mobile devices in 3G networks. Finally, we proposed low-delay and low-power approaches for video transmission over wireless personal area networks, including......Constrained resources like memory, power, bandwidth and delay requirements in many mobile systems pose limitations for video applications. Standard approaches for video compression and transmission do not always satisfy system requirements. In this thesis we have shown that it is possible to modify...

Quality control of diagnostic x-ray units

International Nuclear Information System (INIS)

Marinkovic, O.; Milacic, S.; Jovicic, D.; Tanaskovic, I.

2001-01-01

The quality control program for diagnostic x-ray units has started at the Institute of Occupational and Radiological Health during 1990. It includes, among other measurements, reproducibility of dose, high voltage and exposure time. Dose reproducibility was less than 5% for 70% of tested x-ray units. The exposure time and high voltage reproducibility were less than 5% in 60% cases. The cassettes with amplifying foils made from components of rare earth are used in 10% of all x-ray departments. It is very important to work as much as it is possible to modernize general infrastructure as the radiological protection of patients would be better. (author)

Segmentation of object-based video of gaze communication

DEFF Research Database (Denmark)

Aghito, Shankar Manuel; Stegmann, Mikkel Bille; Forchhammer, Søren

2005-01-01

Aspects of video communication based on gaze interaction are considered. The overall idea is to use gaze interaction to control video, e.g. for video conferencing. Towards this goal, animation of a facial mask is demonstrated. The animation is based on images using Active Appearance Models (AAM......). Good quality reproduction of (low-resolution) coded video of an animated facial mask as low as 10-20 kbit/s using MPEG-4 object based video is demonstated....

Quality control of conventional diagnostic radiology equipment in Serbia and Montenegro

International Nuclear Information System (INIS)

Ciraj, O.; Kosutic, D.; Markovic, S.

2003-01-01

There are more than 1500 diagnostic X-ray tubes in service in Serbia and Montenegro. Diagnostic X-ray equipment is checked on annual basis. X-ray equipment Qc protocols have been adopted from several international standards and guidelines [1,2], which have been modified according our practice and measuring equipment. According our inventory, about one half of all installed units is used for conventional X-ray diagnostics, 10% are mobile units, 2% of all in units in operation are mammographic devices an another 2% are computed tomography units. In addition there are about 600 dental X-ray units, which is 36% of all units. It is worth mentioning that almost 30 % of all installed units have single-phase generators, another 25% are tree phase (six and twelve pulse) generators and nearly 9% are high frequency units. Majority of units was installed more than 25 years ago. The Quality Control (QC) in radiography is a central part of QA programme, which deals with equipment maintenance and monitoring. QA in diagnostic radiology is a mean of maintaining standards in imaging and working towards minimizing patient and staff doses. As a part of QA programme in diagnostic radiology, the performance characteristics of 96 conventional X-ray units were measured in six months period during 2003. The diagnostic units were located in hospitals all over the country. They represent 25% of the total conventional diagnostic units of the country. About one half of measured X-ray units were new-installed. QC program has positive effect on X-ray equipment performance in a period of a few years. It is essential to perform QC tests for all installed X-ray units at least on annual basis. This would lead to production of consistent X-ray images, with minimal retake rate and hence, will contribute to decreasing of the patient dose. Patient doses are determined by multitude factors which interact in very complicated manner. It is very important to perform real patient dose measurements in

An overview of the International Electrotechnical Commission's activities on quality assurance in diagnostic radiology

International Nuclear Information System (INIS)

Julius, H.W.; Ammers, H. van; Henshaw, E.T.

1989-01-01

In 1981, the International Electrotechnical Commission Sub-committee 62B set up a Working Group to deal with quality assurance in diagnostic X-ray departments and, more specifically, to develop international standards describing procedures to test the constancy of parameters of diagnostic X-ray Departments, four draft standards on specific topics, seven more documents are in advanced stage, and several others under consideration. According to the approach adopted by the Working Group, these documents are meant to assist in establishing quality assurance programmes in hospitals and provide guidance on how to perform tests and interpret results. This paper reveals the general philosophy behind the activities of the Working Group as well as some details of the standards produced so far, with emphasis on physical parameters of diagnostic X-ray installations and proposed criteria for satisfactory performance. (author)

Video based OER: Production, discovery, dissemination

OpenAIRE

Gibbs, Graham R.

2012-01-01

This paper reports lessons learned from a range of ESRC, HEA and Jisc funded projects. Four dimensions will be discussed, economic costs, quality, dissemination and pedagogy.\\ud \\ud Cost issues include the expense of making video, and the variety of skills and expertise required such as interviewing, scripting and editing. Quality issues are similar to those in broadcast video but not as great. However, there are specific requirements for special needs and issues around copyright and licensin...

Can student-produced video transform university teaching?

DEFF Research Database (Denmark)

2011-01-01

as preparation for the two week intensive field course. The overall objective of the redesign was to modernize and improve the quality of the students learning experience, by exploring the potentials of video and online tools to create flexible, student-centered and student-activating education. The student...... produced three types of videos during the course: Video 1 was independently produced by the students, guided by online tasks and instructions. These videos were student produced learning material, showing cases from all over Europe. The videos was collected and presented in a "visual database" in Google...

Content-Aware Video Adaptation under Low-Bitrate Constraint

Directory of Open Access Journals (Sweden)

Hsiao Ming-Ho

2007-01-01

Full Text Available With the development of wireless network and the improvement of mobile device capability, video streaming is more and more widespread in such an environment. Under the condition of limited resource and inherent constraints, appropriate video adaptations have become one of the most important and challenging issues in wireless multimedia applications. In this paper, we propose a novel content-aware video adaptation in order to effectively utilize resource and improve visual perceptual quality. First, the attention model is derived from analyzing the characteristics of brightness, location, motion vector, and energy features in compressed domain to reduce computation complexity. Then, through the integration of attention model, capability of client device and correlational statistic model, attractive regions of video scenes are derived. The information object- (IOB- weighted rate distortion model is used for adjusting the bit allocation. Finally, the video adaptation scheme dynamically adjusts video bitstream in frame level and object level. Experimental results validate that the proposed scheme achieves better visual quality effectively and efficiently.

Radiation exposure and image quality in X-ray diagnostic radiology. Physical principles and clinical applications. 2. ed.

International Nuclear Information System (INIS)

Saebel, Manfred; Aichinger, Horst; Dierker, Joachim; Joite-Barfuss, Sigrid

2012-01-01

Diagnostic X-rays are the largest contributor to radiation exposure to the general population, and protecting the patient from radiation damage is a major aim of modern health policy. Once the decision has been taken to use ionising radiation for imaging in a particular patient, it is necessary to optimize the image acquisition process taking into account the diagnostic quality of the images and the radiation dose to the patient. Both image quality and radiation dose are affected by a number of parameters, knowledge of which permits scientifically based decision making. The authors of this second edition of Radiation Exposure and Image Quality in X-ray Diagnostic Radiology have spent many years studying the optimization of radiological imaging. In this book they present in detail the basic physical principles of diagnostic radiology and their application to clinical problems. Particular attention is devoted to evaluation of the dose to the patient, the influence of scattered radiation on image quality, the use of antiscatter grids, and optimization of image quality and dose. The final section is a supplement containing tables of data and graphical depictions of X-ray spectra, interaction coefficients, characteristics of X-ray beams, and other aspects relevant to patient dose calculations. In addition, a complementary CD-ROM contains a user-friendly Excel file database covering these aspects that can be used in the reader's own programs. Since the first edition, the text, figures, tables, and references have all been thoroughly updated, and more detailed attention is now paid to image quality and radiation exposure when using digital imaging and computed tomography. This book will be an invaluable aid to medical physicists when performing calculations relating to patient dose and image quality, and will also prove useful for diagnostic radiologists and engineers. (orig.)

Student’s Video Production as Formative Assessment

Directory of Open Access Journals (Sweden)

Eduardo Gama

2017-04-01

Full Text Available Learning assessments are subject of discussion both in their theoretical and practical approaches. The process of measuring learning in physics by high school students, either qualitatively or quantitatively, is one in which it should be possible to identify not only the concepts and contents students failed to achieve but also the reasons for the failure. We propose that students’ video production offers a very effective formative assessment tool to teachers: as a formative assessment, it produces information that allows the understanding of where and when the learning process succeeded or failed, of identifying, as a subject or as a group, the deficiencies or misunderstandings related to the theme under analysis and their interpretation by students, and it provides also a different kind of assessment, related to some other life skills, such as ability to carry on a project till its conclusion and to work cooperatively. In this paper, we describe the use of videos produced by high school students as an assessment resource. The students were asked to prepare a short video, which was then presented to the whole group and discussed. The videos reveal aspects of students’ difficulties that usually do not appear in formal assessments such as tests and questionnaires. After the use of the videos as a component of classroom assessments and the use of the discussions to rethink learning activities in the group, the videos were analysed and classified in various categories. This analysis showed a strong correlation between the technical quality of the video and the content quality of the students’ argumentation. Also, it was shown that the students do not prepare their video based on quick and easy production; they usually choose forms of video production that require careful planning and implementation, and this reflects directly on the overall quality of the video and of the learning process.

Secured web-based video repository for multicenter studies.

Science.gov (United States)

Yan, Ling; Hicks, Matt; Winslow, Korey; Comella, Cynthia; Ludlow, Christy; Jinnah, H A; Rosen, Ami R; Wright, Laura; Galpern, Wendy R; Perlmutter, Joel S

2015-04-01

We developed a novel secured web-based dystonia video repository for the Dystonia Coalition, part of the Rare Disease Clinical Research network funded by the Office of Rare Diseases Research and the National Institute of Neurological Disorders and Stroke. A critical component of phenotypic data collection for all projects of the Dystonia Coalition includes a standardized video of each participant. We now describe our method for collecting, serving and securing these videos that is widely applicable to other studies. Each recruiting site uploads standardized videos to a centralized secured server for processing to permit website posting. The streaming technology used to view the videos from the website does not allow downloading of video files. With appropriate institutional review board approval and agreement with the hosting institution, users can search and view selected videos on the website using customizable, permissions-based access that maintains security yet facilitates research and quality control. This approach provides a convenient platform for researchers across institutions to evaluate and analyze shared video data. We have applied this methodology for quality control, confirmation of diagnoses, validation of rating scales, and implementation of new research projects. We believe our system can be a model for similar projects that require access to common video resources. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quality assurance in diagnostic radiology in Hungary - first experiences in acceptance testing

International Nuclear Information System (INIS)

Porubszky, T.; Pellet, S.; Ballay, L.; Talian, L.; Giczi, F.

2003-01-01

It is a general experience that optimum imaging with minimum patient doses, moreover, the safe operation and long life of X-ray equipment can be assured by regular measurement of technical parameters and checking of their constancy (routine performance testing) only. These tests are generally known as quality control, while together with the so-called corrective actions and its management it is called (physical-technical) quality assurance (QA). In the European Union, Directive 97/43/EURATOM about radiation protection of patients requires - among others - the good practice of (physical-technical) quality assurance. In Hungary, Decree No. 31/2001. (X.3.) of the Minister of Health harmonizes all of its requirements. Acceptance testing of new diagnostic X-ray equipment is assigned to NPHC-NRIRR. QA has been a daily practice in radiation therapy and nuclear medicine for a long time. A National Patient Dose Assessment Programme has also successfully run since 1989. We had, however, only few preliminaries in QA in diagnostic radiology in the second half of the eighties. Nowadays there are running QA programmes in some hospitals and mammography centres. he testing activity of our institute is independent from manufacturers, it is run within the frame of an accredited testing laboratory, using calibrated measuring instruments and based on valid international standards. So the started way of implementing QA in diagnostic radiology needs a lot of further efforts, adapting experiences of other countries, and also some financial help to reach an acceptable level in the EU. (authors)

MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

Science.gov (United States)

Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Triviño

2013-01-01

In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

The ASDEX upgrade digital video processing system for real-time machine protection

Energy Technology Data Exchange (ETDEWEB)

Drube, Reinhard, E-mail: reinhard.drube@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Neu, Gregor [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Cole, Richard H.; Lüddecke, Klaus [Unlimited Computer Systems GmbH, Seeshaupterstr. 15, 82393 Iffeldorf (Germany); Lunt, Tilmann; Herrmann, Albrecht [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

2013-11-15

Highlights: • We present the Real-Time Video diagnostic system of ASDEX Upgrade. • We show the implemented image processing algorithms for machine protection. • The way to achieve a robust operating multi-threading Real-Time system is described. -- Abstract: This paper describes the design, implementation, and operation of the Video Real-Time (VRT) diagnostic system of the ASDEX Upgrade plasma experiment and its integration with the ASDEX Upgrade Discharge Control System (DCS). Hot spots produced by heating systems erroneously or accidentally hitting the vessel walls, or from objects in the vessel reaching into the plasma outer border, show up as bright areas in the videos during and after the reaction. A system to prevent damage to the machine by allowing for intervention in a running discharge of the experiment was proposed and implemented. The VRT was implemented on a multi-core real-time Linux system. Up to 16 analog video channels (color and b/w) are acquired and multiple regions of interest (ROI) are processed on each video frame. Detected critical states can be used to initiate appropriate reactions – e.g. gracefully terminate the discharge. The system has been in routine operation since 2007.

Selectively De-animating and Stabilizing Videos

Science.gov (United States)

2014-12-11

motions intact. Video textures [97, 65, 7, 77] are a well-known approach for seamlessly looping stochastic motions. Like cinema - graphs, a video...domain of input videos to portraits. We all use portrait photographs to express our identities online. Portraits are often the first visuals seen by...quality of our result, we show some comparisons of our automated cinema - graphs against our user driven method described in Chapter 3 in Figure 4.7

Study on the quality assurance of diagnostic X-ray machines and assessment of the absorbed dose to patients

Science.gov (United States)

Hassan, G. M.; Rabie, N.; Mustafa, K. A.; Abdel-Khalik, S. S.

2012-09-01

Radiation exposure and image quality in X-ray diagnostic radiology provide a clear understanding of the relationship between the radiation dose delivered to a patient and image quality in optimizing medical diagnostic radiology. Because a certain amount of radiation is unavoidably delivered to patients, this should be as low as reasonably achievable. Several X-ray diagnostic machines were used at different medical diagnostic centers in Egypt for studying the beam quality and the dose delivered to the patient. This article studies the factors affecting the beam quality, such as the kilo-volt peak (kVp), exposure time (mSc), tube current (mAs) and the absorbed dose in (μGy) for different examinations. The maximum absorbed dose measured per mAs was 594±239 and 12.5±3.7 μGy for the abdomen and the chest, respectively, while the absorbed dose at the elbow was 18±6 μGy, which was the minimum dose recorded. The compound and expanded uncertainties accompanying these measurements were 4±0.35% and 8±0.7%, respectively. The measurements were done through quality control tests as acceptance procedures.

Descriptive analysis of YouTube music therapy videos.

Science.gov (United States)

Gooding, Lori F; Gregory, Dianne

2011-01-01

The purpose of this study was to conduct a descriptive analysis of music therapy-related videos on YouTube. Preliminary searches using the keywords music therapy, music therapy session, and "music therapy session" resulted in listings of 5000, 767, and 59 videos respectively. The narrowed down listing of 59 videos was divided between two investigators and reviewed in order to determine their relationship to actual music therapy practice. A total of 32 videos were determined to be depictions of music therapy sessions. These videos were analyzed using a 16-item investigator-created rubric that examined both video specific information and therapy specific information. Results of the analysis indicated that audio and visual quality was adequate, while narrative descriptions and identification information were ineffective in the majority of the videos. The top 5 videos (based on the highest number of viewings in the sample) were selected for further analysis in order to investigate demonstration of the Professional Level of Practice Competencies set forth in the American Music Therapy Association (AMTA) Professional Competencies (AMTA, 2008). Four of the five videos met basic competency criteria, with the quality of the fifth video precluding evaluation of content. Of particular interest is the fact that none of the videos included credentialing information. Results of this study suggest the need to consider ways to ensure accurate dissemination of music therapy-related information in the YouTube environment, ethical standards when posting music therapy session videos, and the possibility of creating AMTA standards for posting music therapy related video.

Web-video-mining-supported workflow modeling for laparoscopic surgeries.

Science.gov (United States)

Liu, Rui; Zhang, Xiaoli; Zhang, Hao

2016-11-01

As quality assurance is of strong concern in advanced surgeries, intelligent surgical systems are expected to have knowledge such as the knowledge of the surgical workflow model (SWM) to support their intuitive cooperation with surgeons. For generating a robust and reliable SWM, a large amount of training data is required. However, training data collected by physically recording surgery operations is often limited and data collection is time-consuming and labor-intensive, severely influencing knowledge scalability of the surgical systems. The objective of this research is to solve the knowledge scalability problem in surgical workflow modeling with a low cost and labor efficient way. A novel web-video-mining-supported surgical workflow modeling (webSWM) method is developed. A novel video quality analysis method based on topic analysis and sentiment analysis techniques is developed to select high-quality videos from abundant and noisy web videos. A statistical learning method is then used to build the workflow model based on the selected videos. To test the effectiveness of the webSWM method, 250 web videos were mined to generate a surgical workflow for the robotic cholecystectomy surgery. The generated workflow was evaluated by 4 web-retrieved videos and 4 operation-room-recorded videos, respectively. The evaluation results (video selection consistency n-index ≥0.60; surgical workflow matching degree ≥0.84) proved the effectiveness of the webSWM method in generating robust and reliable SWM knowledge by mining web videos. With the webSWM method, abundant web videos were selected and a reliable SWM was modeled in a short time with low labor cost. Satisfied performances in mining web videos and learning surgery-related knowledge show that the webSWM method is promising in scaling knowledge for intelligent surgical systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Despeckle filtering for ultrasound imaging and video II selected applications

CERN Document Server

Loizou, Christos P

2015-01-01

In ultrasound imaging and video visual perception is hindered by speckle multiplicative noise that degrades the quality. Noise reduction is therefore essential for improving the visual observation quality or as a pre-processing step for further automated analysis, such as image/video segmentation, texture analysis and encoding in ultrasound imaging and video. The goal of the first book (book 1 of 2 books) was to introduce the problem of speckle in ultrasound image and video as well as the theoretical background, algorithmic steps, and the MatlabTM for the following group of despeckle filters:

European specialist porphyria laboratories: diagnostic strategies, analytical quality, clinical interpretation, and reporting as assessed by an external quality assurance program.

Science.gov (United States)

Aarsand, Aasne K; Villanger, Jørild H; Støle, Egil; Deybach, Jean-Charles; Marsden, Joanne; To-Figueras, Jordi; Badminton, Mike; Elder, George H; Sandberg, Sverre

2011-11-01

The porphyrias are a group of rare metabolic disorders whose diagnosis depends on identification of specific patterns of porphyrin precursor and porphyrin accumulation in urine, blood, and feces. Diagnostic tests for porphyria are performed by specialized laboratories in many countries. Data regarding the analytical and diagnostic performance of these laboratories are scarce. We distributed 5 sets of multispecimen samples from different porphyria patients accompanied by clinical case histories to 18-21 European specialist porphyria laboratories/centers as part of a European Porphyria Network organized external analytical and postanalytical quality assessment (EQA) program. The laboratories stated which analyses they would normally have performed given the case histories and reported results of all porphyria-related analyses available, interpretative comments, and diagnoses. Reported diagnostic strategies initially showed considerable diversity, but the number of laboratories applying adequate diagnostic strategies increased during the study period. We found an average interlaboratory CV of 50% (range 12%-152%) for analytes in absolute concentrations. Result normalization by forming ratios to the upper reference limits did not reduce this variation. Sixty-five percent of reported results were within biological variation-based analytical quality specifications. Clinical interpretation of the obtained analytical results was accurate, and most laboratories established the correct diagnosis in all distributions. Based on a case-based EQA scheme, variations were apparent in analytical and diagnostic performance between European specialist porphyria laboratories. Our findings reinforce the use of EQA schemes as an essential tool to assess both analytical and diagnostic processes and thereby to improve patient care in rare diseases.

The emerging High Efficiency Video Coding standard (HEVC)

International Nuclear Information System (INIS)

Raja, Gulistan; Khan, Awais

2013-01-01

High definition video (HDV) is becoming popular day by day. This paper describes the performance analysis of latest upcoming video standard known as High Efficiency Video Coding (HEVC). HEVC is designed to fulfil all the requirements for future high definition videos. In this paper, three configurations (intra only, low delay and random access) of HEVC are analyzed using various 480p, 720p and 1080p high definition test video sequences. Simulation results show the superior objective and subjective quality of HEVC

Quality control for diagnostic oral microbiology laboratories in European countries

Directory of Open Access Journals (Sweden)

Andrew J. Smith

2011-11-01

Full Text Available Participation in diagnostic microbiology internal and external quality control (QC processes is good laboratory practice and an essential component of a quality management system. However, no QC scheme for diagnostic oral microbiology existed until 2009 when the Clinical Oral Microbiology (COMB Network was created. At the European Oral Microbiology Workshop in 2008, 12 laboratories processing clinical oral microbiological samples were identified. All these were recruited to participate into the study and six laboratories from six European countries completed both the online survey and the first QC round. Three additional laboratories participated in the second round. Based on the survey, European oral microbiology laboratories process a significant (mean per laboratory 4,135 number of diagnostic samples from the oral cavity annually. A majority of the laboratories did not participate in any internal or external QC programme and nearly half of the laboratories did not have standard operating procedures for the tests they performed. In both QC rounds, there was a large variation in the results, interpretation and reporting of antibiotic susceptibility testing among the laboratories. In conclusion, the results of this study demonstrate the need for harmonisation of laboratory processing methods and interpretation of results for oral microbiology specimens. The QC rounds highlighted the value of external QC in evaluating the efficacy and safety of processes, materials and methods used in the laboratory. The use of standardised methods is also a prerequisite for multi-centre epidemiological studies that can provide important information on emerging microbes and trends in anti-microbial susceptibility for empirical prescribing in oro-facial infections.

Quality-of-Life Differences among Diagnostic Subgroups of Children Receiving Ventilating Tubes for Otitis Media

DEFF Research Database (Denmark)

Heidemann, Christian Hamilton; Lauridsen, Henrik Hein; Kjeldsen, Anette Drøhse

2015-01-01

OBJECTIVE: The pathological picture may differ considerably between diagnostic subgroups of children with otitis media receiving ventilating tubes. The aims of this study are to investigate differences in quality of life among diagnostic subgroups of children treated with ventilating tubes...... media with effusion (OME), and 38% mixed diagnosis of rAOM and OME (rAOM/OME). There were no significant differences between children diagnosed with rAOM and children diagnosed with rAOM/OME. However, these children had a significantly poorer quality of life at baseline compared with children diagnosed...... with only OME. Factors associated with clinical success included a diagnosis of rAOM, number of interrupted nights, physician visits, and canceled social activities due to OM. CONCLUSIONS: Results highlight the importance of distinguishing between diagnostic subgroups of children having ventilating tube...

Quality control in diagnostic radiology. Historical development and present status in Europe

International Nuclear Information System (INIS)

Michael Moores, B.

2007-01-01

Complete test of publication follows. Quality control is now an accepted activity within the overall radiation protection framework for diagnostic radiology. Indeed it is now a legal requirement within Member States specified in EC Directives that establish the basic requirements for radiation protection in medicine. This was not always the case and its historical development can be considered in three parts: 1) The development of test procedures and standardisation of practices; 2) Harmonisation of initiatives and the creation of a European dimension in such practices; 3) Its role and function in a changing and evolving technological environment - current status and future needs. The development of tests methods for diagnostic X-ray equipment was initially intimately related to the development of a scientific basis for the X-ray imaging process. Knowledge of the physical basis for image production in film-screen and fluoroscopic processes required the definition and specification and measurement of particular parameters within the image forming chain. The development of test methods and the necessary measuring equipment involved ongoing research and development by physical scientists throughout Europe and North America. However, the many different approaches employed meant that results of measurements could not always be compared. However, once acceptable test methods and equipment had been developed it was possible to standardise practices through the development of test protocols. In 1980 a foundation for collective European actions was established through the EC radiation protection research and development programme. This helped to establish a European wide forum for actions in the field of medical radiation protection including quality control. These initiatives were driven by EC Directives, which were concerned with protection of the worker, general public and patients from medical practices that utilised ionising radiation. Multi national research

Rate-distortion optimization for compressive video sampling

Science.gov (United States)

Liu, Ying; Vijayanagar, Krishna R.; Kim, Joohee

2014-05-01

The recently introduced compressed sensing (CS) framework enables low complexity video acquisition via sub- Nyquist rate sampling. In practice, the resulting CS samples are quantized and indexed by finitely many bits (bit-depth) for transmission. In applications where the bit-budget for video transmission is constrained, rate- distortion optimization (RDO) is essential for quality video reconstruction. In this work, we develop a double-level RDO scheme for compressive video sampling, where frame-level RDO is performed by adaptively allocating the fixed bit-budget per frame to each video block based on block-sparsity, and block-level RDO is performed by modelling the block reconstruction peak-signal-to-noise ratio (PSNR) as a quadratic function of quantization bit-depth. The optimal bit-depth and the number of CS samples are then obtained by setting the first derivative of the function to zero. In the experimental studies the model parameters are initialized with a small set of training data, which are then updated with local information in the model testing stage. Simulation results presented herein show that the proposed double-level RDO significantly enhances the reconstruction quality for a bit-budget constrained CS video transmission system.

Robust Watermarking of Video Streams

Directory of Open Access Journals (Sweden)

T. Polyák

2006-01-01

Full Text Available In the past few years there has been an explosion in the use of digital video data. Many people have personal computers at home, and with the help of the Internet users can easily share video files on their computer. This makes possible the unauthorized use of digital media, and without adequate protection systems the authors and distributors have no means to prevent it.Digital watermarking techniques can help these systems to be more effective by embedding secret data right into the video stream. This makes minor changes in the frames of the video, but these changes are almost imperceptible to the human visual system. The embedded information can involve copyright data, access control etc. A robust watermark is resistant to various distortions of the video, so it cannot be removed without affecting the quality of the host medium. In this paper I propose a video watermarking scheme that fulfills the requirements of a robust watermark. 

Violent Video Games and Children’s Aggressive Behaviors

Directory of Open Access Journals (Sweden)

Luca Milani

2015-08-01

Full Text Available The literature provides some evidence that the use of violent video games increases the risk for young people to develop aggressive cognitions and even behaviors. We aimed to verify whether exposure to violent video games is linked to problems of aggression in a sample of Italian children. Four questionnaires were administered to 346 children between 7 and 14 years of age, attending primary and secondary schools in Northern Italy. Variables measured were externalization, quality of interpersonal relationships, aggression, quality of coping strategies, and parental stress. Participants who preferred violent games showed higher scores for externalization and aggression. The use of violent video games and age were linked to higher levels of aggression, coping strategies, and the habitual video game weekly consumption of participants. Our data confirm the role of violent video games as risk factors for problems of aggressive behavior and of externalization in childhood and early adolescence.

Large-video-display-format conversion

NARCIS (Netherlands)

Haan, de G.

2000-01-01

High-quality video-format converters apply motion estimation and motion compensation to prevent jitter resulting from picture-rate conversion, and aliasing due to de-interlacing, in sequences with motion. Although initially considered as too expensive, high-quality conversion is now economically

Semantic web technologies for video surveillance metadata

OpenAIRE

Poppe, Chris; Martens, Gaëtan; De Potter, Pieterjan; Van de Walle, Rik

2012-01-01

Video surveillance systems are growing in size and complexity. Such systems typically consist of integrated modules of different vendors to cope with the increasing demands on network and storage capacity, intelligent video analytics, picture quality, and enhanced visual interfaces. Within a surveillance system, relevant information (like technical details on the video sequences, or analysis results of the monitored environment) is described using metadata standards. However, different module...

Quality criteria in diagnostic radiology of the skull

International Nuclear Information System (INIS)

Friedmann, G.

1985-01-01

Diagnostic survey radiology of the skull relies on pictures to be taken if indicated and to meet all conceivable requirements. Those radiograph directions and projections were selected out of the profusion of known and described ones which allow both as small a number of pictures and as comprehensive a demonstration of all skull sections and1structures as possible. With this in mind, quality criteria for plain radiographs of the skull taken laterally and sagittably, for partial radiographs of the visceral cranium including orbit and of the base of the skull including petrons bone are described. (orig./MG) [de

The experiences of health-related quality of life in patients with nonspecific symptoms who undergo a diagnostic evaluation for cancer

DEFF Research Database (Denmark)

Moseholm, Ellen; Lindhardt, Bjarne Oerskov; Rydahl-Hansen, Susan

2017-01-01

The diagnostic phase of cancer can affect health-related quality of life (HRQoL). The aim of this study was to investigate how patients with nonspecific symptoms experience HRQoL while undergoing diagnostic evaluations for cancer. Twenty-one participants who had completed a fast-track evaluation...... of Cancer Quality of Life questionnaire (EORCT-QLQ-C30). Data analysis was based on qualitative content analysis by Krippendorff. The analysis generated six categories: symptoms, physical-, role-, emotional-, cognitive- and social functioning, and the diagnostic fast-track experience. From these categories......, a main theme was identified: Health-related quality of life is not solely affected by the diagnostic process. The results provide a comprehensive understanding of HRQoL in the diagnostic phase of possible cancer, which can be used not only to enhance evidence-based care, but also in the interpretation...

MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

Directory of Open Access Journals (Sweden)

Behrang Barekatain

Full Text Available In recent years, Random Network Coding (RNC has emerged as a promising solution for efficient Peer-to-Peer (P2P video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

Design considerations for computationally constrained two-way real-time video communication

Science.gov (United States)

Bivolarski, Lazar M.; Saunders, Steven E.; Ralston, John D.

2009-08-01

Today's video codecs have evolved primarily to meet the requirements of the motion picture and broadcast industries, where high-complexity studio encoding can be utilized to create highly-compressed master copies that are then broadcast one-way for playback using less-expensive, lower-complexity consumer devices for decoding and playback. Related standards activities have largely ignored the computational complexity and bandwidth constraints of wireless or Internet based real-time video communications using devices such as cell phones or webcams. Telecommunications industry efforts to develop and standardize video codecs for applications such as video telephony and video conferencing have not yielded image size, quality, and frame-rate performance that match today's consumer expectations and market requirements for Internet and mobile video services. This paper reviews the constraints and the corresponding video codec requirements imposed by real-time, 2-way mobile video applications. Several promising elements of a new mobile video codec architecture are identified, and more comprehensive computational complexity metrics and video quality metrics are proposed in order to support the design, testing, and standardization of these new mobile video codecs.

DEFINITION AND ANALYSIS OF MOTION ACTIVITY AFTER-STROKE PATIENT FROM THE VIDEO STREAM

Directory of Open Access Journals (Sweden)

M. Yu. Katayev

2014-01-01

Full Text Available This article describes an approach to the assessment of motion activity of man in after-stroke period, allowing the doctor to get new information to give a more informed recommendations on rehabilitation treatment than in traditional approaches. Consider description of the hardware-software complex for determination and analysis of motion activity after-stroke patient for the video stream. The article provides a description of the complex, its algorithmic filling and the results of the work on the example of processing of the actual data. The algorithms and technology to significantly accelerate the gait analysis and improve the quality of diagnostics post-stroke patients.

Skype resilience to high motion videos

NARCIS (Netherlands)

Exarchakos, G.; Druda, L.; Menkovski, V.; Bellavista, P.; Liotta, A.

Skype is one of the most popular video call services in the current Internet world. One of its strengths is the use of an adaptive mechanism to match the constraints of the underlying network. This work is focused on how this mechanism can maximize the video quality as perceived by the viewers using

A Novel System for Supporting Autism Diagnosis Using Home Videos: Iterative Development and Evaluation of System Design.

Science.gov (United States)

Nazneen, Nazneen; Rozga, Agata; Smith, Christopher J; Oberleitner, Ron; Abowd, Gregory D; Arriaga, Rosa I

2015-06-17

Observing behavior in the natural environment is valuable to obtain an accurate and comprehensive assessment of a child's behavior, but in practice it is limited to in-clinic observation. Research shows significant time lag between when parents first become concerned and when the child is finally diagnosed with autism. This lag can delay early interventions that have been shown to improve developmental outcomes. To develop and evaluate the design of an asynchronous system that allows parents to easily collect clinically valid in-home videos of their child's behavior and supports diagnosticians in completing diagnostic assessment of autism. First, interviews were conducted with 11 clinicians and 6 families to solicit feedback from stakeholders about the system concept. Next, the system was iteratively designed, informed by experiences of families using it in a controlled home-like experimental setting and a participatory design process involving domain experts. Finally, in-field evaluation of the system design was conducted with 5 families of children (4 with previous autism diagnosis and 1 child typically developing) and 3 diagnosticians. For each family, 2 diagnosticians, blind to the child's previous diagnostic status, independently completed an autism diagnosis via our system. We compared the outcome of the assessment between the 2 diagnosticians, and between each diagnostician and the child's previous diagnostic status. The system that resulted through the iterative design process includes (1) NODA smartCapture, a mobile phone-based application for parents to record prescribed video evidence at home; and (2) NODA Connect, a Web portal for diagnosticians to direct in-home video collection, access developmental history, and conduct an assessment by linking evidence of behaviors tagged in the videos to the Diagnostic and Statistical Manual of Mental Disorders criteria. Applying clinical judgment, the diagnostician concludes a diagnostic outcome. During field

Evaluation of educational content of YouTube videos relating to neurogenic bladder and intermittent catheterization.

Science.gov (United States)

Ho, Matthew; Stothers, Lynn; Lazare, Darren; Tsang, Brian; Macnab, Andrew

2015-01-01

Many patients conduct internet searches to manage their own health problems, to decide if they need professional help, and to corroborate information given in a clinical encounter. Good information can improve patients' understanding of their condition and their self-efficacy. Patients with spinal cord injury (SCI) featuring neurogenic bladder (NB) require knowledge and skills related to their condition and need for intermittent catheterization (IC). Information quality was evaluated in videos accessed via YouTube relating to NB and IC using search terms "neurogenic bladder intermittent catheter" and "spinal cord injury intermittent catheter." Video content was independently rated by 3 investigators using criteria based on European Urological Association (EAU) guidelines and established clinical practice. In total, 71 videos met the inclusion criteria. Of these, 12 (17%) addressed IC and 50 (70%) contained information on NB. The remaining videos met inclusion criteria, but did not contain information relevant to either IC or NB. Analysis indicated poor overall quality of information, with some videos with information contradictory to EAU guidelines for IC. High-quality videos were randomly distributed by YouTube. IC videos featuring a healthcare narrator scored significantly higher than patient-narrated videos, but not higher than videos with a merchant narrator. About half of the videos contained commercial content. Some good-quality educational videos about NB and IC are available on YouTube, but most are poor. The videos deemed good quality were not prominently ranked by the YouTube search algorithm, consequently user access is less likely. Study limitations include the limit of 50 videos per category and the use of a de novo rating tool. Information quality in videos with healthcare narrators was not higher than in those featuring merchant narrators. Better material is required to improve patients' understanding of their condition.

Establishing the standard X-ray beam qualities for calibration of dosimeters used in diagnostic radiology following IAEA-TRS457

International Nuclear Information System (INIS)

Duong Van Trieu; Ho Quang Tuan; Bui Duc Ky

2014-01-01

The determination of the patient dose needs to provide a reference dose for the patient that reference dose levels to assess the relative risk during X- ray diagnostic. This mission, We had established a number of standard beam qualities to perform calibrations of diagnostic dosimeters and methods of measuring patient dose in X-ray diagnostic. At radiation dosimetry room, we had establish RQR2, RQR3, RQR4, RQR5, RQR6 beam qualities based on IAEA-TRS457 documentation with homogeneity coefficient (h) for each beam quality in the range 0.7 - 0.8, and haft-value layers HVL1, HVL2 of experimental and IAEA is different about 10%. Established calibration method for diagnostic dosimeters as KAP meters, UNFORS dosimeters, and the TLD dosimeters, practical measurements of entrance surface air kerma on Shimadzu X-ray machines used phantom. (author)

Watermarking textures in video games

Science.gov (United States)

Liu, Huajian; Berchtold, Waldemar; Schäfer, Marcel; Lieb, Patrick; Steinebach, Martin

2014-02-01

Digital watermarking is a promising solution to video game piracy. In this paper, based on the analysis of special challenges and requirements in terms of watermarking textures in video games, a novel watermarking scheme for DDS textures in video games is proposed. To meet the performance requirements in video game applications, the proposed algorithm embeds the watermark message directly in the compressed stream in DDS files and can be straightforwardly applied in watermark container technique for real-time embedding. Furthermore, the embedding approach achieves high watermark payload to handle collusion secure fingerprinting codes with extreme length. Hence, the scheme is resistant to collusion attacks, which is indispensable in video game applications. The proposed scheme is evaluated in aspects of transparency, robustness, security and performance. Especially, in addition to classical objective evaluation, the visual quality and playing experience of watermarked games is assessed subjectively in game playing.

CHALLENGES IN SETTING UP QUALITY CONTROL IN DIAGNOSTIC RADIOLOGY FACILITIES IN NIGERIA.

Science.gov (United States)

Inyang, S O; Egbe, N O; Ekpo, E

2015-01-01

The Nigerian Nuclear Regulatory Authority (NNRA) was established to regulate and control the use of radioactive and radiation emitting sources in Nigeria. Quality control (QC) on diagnostic radiology equipment form part of the fundamental requirements for the authorization of diagnostic radiology facilities in the Country. Some quality control tests (output, exposure linearity and reproducibility) were measured on the x-ray machines in the facilities that took part in the study. Questionnaire was developed to evaluate the frequencies at which QC tests were conducted in the facilities and the challenges in setting up QC. Results show great variation in the values of the QC parameters measured. Inadequate cooperation by facilities management, lack of QC equipment and insufficient staff form the major challenges in setting up QC in the facilities under study. The responses on the frequencies at which QC tests should be conducted did not correspond to the recommended standards; indicating that personnel were not familiar with QC implementation and may require further training on QC.

Holovideo: Real-time 3D range video encoding and decoding on GPU

Science.gov (United States)

Karpinsky, Nikolaus; Zhang, Song

2012-02-01

We present a 3D video-encoding technique called Holovideo that is capable of encoding high-resolution 3D videos into standard 2D videos, and then decoding the 2D videos back into 3D rapidly without significant loss of quality. Due to the nature of the algorithm, 2D video compression such as JPEG encoding with QuickTime Run Length Encoding (QTRLE) can be applied with little quality loss, resulting in an effective way to store 3D video at very small file sizes. We found that under a compression ratio of 134:1, Holovideo to OBJ file format, the 3D geometry quality drops at a negligible level. Several sets of 3D videos were captured using a structured light scanner, compressed using the Holovideo codec, and then uncompressed and displayed to demonstrate the effectiveness of the codec. With the use of OpenGL Shaders (GLSL), the 3D video codec can encode and decode in realtime. We demonstrated that for a video size of 512×512, the decoding speed is 28 frames per second (FPS) with a laptop computer using an embedded NVIDIA GeForce 9400 m graphics processing unit (GPU). Encoding can be done with this same setup at 18 FPS, making this technology suitable for applications such as interactive 3D video games and 3D video conferencing.

Radiation safety and quality control assurance in X-ray diagnostics 1998; Saeteilyturvallisuus ja laadunvarmistus roentgendiagnostiikassa 1998

Energy Technology Data Exchange (ETDEWEB)

Servomaa, A [ed.

1998-03-01

The report is based on a seminar course of lectures `Radiation safety and quality assurance in X-ray diagnostics 1998` organized by the Radiation and Nuclear Safety Authority (STUK) in Finland. The lectures included actual information on X-ray examinations: methods of quality assurance, methods of measuring and calculating patient doses, examination frequencies, patient doses, occupational doses, and radiation risks. Paediatric X-ray examinations and interventional procedures were the most specific topics. The new Council Directive 97/43/Euratom on medical exposure, and the European Guidelines on quality criteria for diagnostic radiographic images, were discussed in several lectures. Lectures on general radiation threats and preparedness, examples of radiation accidents, and emergency preparedness in hospitals were also included. (editor)

Breast Ultrasound Examination with Video Monitor System: A Satisfaction Survey among Patients

International Nuclear Information System (INIS)

Ryu, Jung Kyu; Kim, Hyun Cheol; Yang, Dal Mo

2010-01-01

The purpose of this study is to assess the patients satisfaction with a newly established video-monitor system and the associated basic items for performing breast ultrasound exams by conducting a survey among the patients. 349 patients were invited to take the survey and they had undergone breast ultrasound examination once during the 3 months after the monitor system has been introduced. The questionnaire was composed of 8 questions, 4 of which were about the basic items such as age, gender and the reason of their taking the breast ultrasound exam, their preference for the gender of the examiner and the desired length of time for the examination. The other 4 question were about their satisfaction with the video monitor. The patients were divided into two groups according to the purposes of taking the exams, which were screening or diagnostic purposes. The results were compared between these 2 groups. The satisfaction with the video monitor system was assessed by using a scoring system that ranged from 1 to 5. For the total patients, the screening group was composed of 124 patients and the diagnostic group was composed of 225. The reasons why the patients wanted to take the examinations in the diagnostic group varied. The questionnaire about the preference of the gender of the examiner showed that 81.5% in the screening group and 79.1% in the diagnostic group preferred a woman doctor. The required, suitable time for the breast ultrasound examination was 5 to 10 minutes or 10 to 15 minutes for about 70% of the patients. The mean satisfaction score for the video monitor system was as high as 3.95 point. The portion of patients in each group who answered over 3 points for their satisfaction with the monitor system was 88.7% and 94.2%, respectively. Our study showed that patients preferred 5-15 minutes for the length of the examination time and a female examiner. We also confirmed high patient satisfaction with the video monitor system

Breast Ultrasound Examination with Video Monitor System: A Satisfaction Survey among Patients

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jung Kyu; Kim, Hyun Cheol; Yang, Dal Mo [East-West Neo Medical Center, Kyung-Hee University, Seoul (Korea, Republic of)

2010-03-15

The purpose of this study is to assess the patients satisfaction with a newly established video-monitor system and the associated basic items for performing breast ultrasound exams by conducting a survey among the patients. 349 patients were invited to take the survey and they had undergone breast ultrasound examination once during the 3 months after the monitor system has been introduced. The questionnaire was composed of 8 questions, 4 of which were about the basic items such as age, gender and the reason of their taking the breast ultrasound exam, their preference for the gender of the examiner and the desired length of time for the examination. The other 4 question were about their satisfaction with the video monitor. The patients were divided into two groups according to the purposes of taking the exams, which were screening or diagnostic purposes. The results were compared between these 2 groups. The satisfaction with the video monitor system was assessed by using a scoring system that ranged from 1 to 5. For the total patients, the screening group was composed of 124 patients and the diagnostic group was composed of 225. The reasons why the patients wanted to take the examinations in the diagnostic group varied. The questionnaire about the preference of the gender of the examiner showed that 81.5% in the screening group and 79.1% in the diagnostic group preferred a woman doctor. The required, suitable time for the breast ultrasound examination was 5 to 10 minutes or 10 to 15 minutes for about 70% of the patients. The mean satisfaction score for the video monitor system was as high as 3.95 point. The portion of patients in each group who answered over 3 points for their satisfaction with the monitor system was 88.7% and 94.2%, respectively. Our study showed that patients preferred 5-15 minutes for the length of the examination time and a female examiner. We also confirmed high patient satisfaction with the video monitor system

The Effect of Signal Quality and Contiguous Word of Mouth on Customer Acquisition for a Video-on-Demand Service

OpenAIRE

Sungjoon Nam; Puneet Manchanda; Pradeep K. Chintagunta

2010-01-01

This paper documents the existence and magnitude of contiguous word-of-mouth effects of signal quality of a video-on-demand (VOD) service on customer acquisition. We operationalize contiguous word-of-mouth effect based on geographic proximity and use behavioral data to quantify the effect. The signal quality for this VOD service is exogenously determined, objectively measured, and spatially uncorrelated. Furthermore, it is unobserved to the potential subscriber and is revealed postadoption. F...

Do Instructional Videos on Sputum Submission Result in Increased Tuberculosis Case Detection? A Randomized Controlled Trial.

Directory of Open Access Journals (Sweden)

Grace Mhalu

Full Text Available We examined the effect of an instructional video about the production of diagnostic sputum on case detection of tuberculosis (TB, and evaluated the acceptance of the video.Randomized controlled trial.We prepared a culturally adapted instructional video for sputum submission. We analyzed 200 presumptive TB cases coughing for more than two weeks who attended the outpatient department of the governmental Municipal Hospital in Mwananyamala (Dar es Salaam, Tanzania. They were randomly assigned to either receive instructions on sputum submission using the video before submission (intervention group, n = 100 or standard of care (control group, n = 100. Sputum samples were examined for volume, quality and presence of acid-fast bacilli by experienced laboratory technicians blinded to study groups.Median age was 39.1 years (interquartile range 37.0-50.0; 94 (47% were females, 106 (53% were males, and 49 (24.5% were HIV-infected. We found that the instructional video intervention was associated with detection of a higher proportion of microscopically confirmed cases (56%, 95% confidence interval [95% CI] 45.7-65.9%, sputum smear positive patients in the intervention group versus 23%, 95% CI 15.2-32.5%, in the control group, p <0.0001, an increase in volume of specimen defined as a volume ≥3ml (78%, 95% CI 68.6-85.7%, versus 45%, 95% CI 35.0-55.3%, p <0.0001, and specimens less likely to be salivary (14%, 95% CI 7.9-22.4%, versus 39%, 95% CI 29.4-49.3%, p = 0.0001. Older age, but not the HIV status or sex, modified the effectiveness of the intervention by improving it positively. When asked how well the video instructions were understood, the majority of patients in the intervention group reported to have understood the video instructions well (97%. Most of the patients thought the video would be useful in the cultural setting of Tanzania (92%.Sputum submission instructional videos increased the yield of tuberculosis cases through better quality of sputum

Quality control of diagnostic x-ray equipment and film processing

International Nuclear Information System (INIS)

1993-01-01

According to the section 40 of the Radiation Act (592/92), the licensee is required in Finland to make the arrangements to control the function of the radiation equipment and related facilities used for medical procedures. The guide explains how quality control can be organized for diagnostic x-ray equipment. It also gives recommendations for constancy tests for conventional x-ray radiographic and fluoroscopic equipment and for film processing. The recommendations are based on the publications and statements of the International Committee for Radiation Protection (ICRP) and standardization organizations. The intention is that the operators of x-ray equipment or the maintenance personnel are able to perform the quality control tests presented in the guide

Processing Decoded Video for Backlight Dimming

DEFF Research Database (Denmark)

Burini, Nino; Korhonen, Jari

rendition of the signals, particularly in the case of LCDs with dynamic local backlight. This thesis shows that it is possible to model LCDs with dynamic backlight to design algorithms that improve the visual quality of 2D and 3D content, and that digital video coding artifacts like blocking or ringing can......Quality of digital image and video signals on TV screens is aected by many factors, including the display technology and compression standards. An accurate knowledge of the characteristics of the display andof the video signals can be used to develop advanced algorithms that improve the visual...... be reduced with post-processing. LCD screens with dynamic local backlight are modeled in their main aspects, like pixel luminance, light diusion and light perception. Following the model, novel algorithms based on optimization are presented and extended, then reduced in complexity, to produce backlights...

Mobile Video in Everyday Social Interactions

Science.gov (United States)

Reponen, Erika; Lehikoinen, Jaakko; Impiö, Jussi

Video recording has become a spontaneous everyday activity for many people, thanks to the video capabilities of modern mobile phones. Internet connectivity of mobile phones enables fluent sharing of captured material even real-time, which makes video an up-and-coming everyday interaction medium. In this article we discuss the effect of the video camera in the social environment, everyday life situations, mainly based on a study where four groups of people used digital video cameras in their normal settings. We also reflect on another study of ours, relating to real-time mobile video communication and discuss future views. The aim of our research is to understand the possibilities in the domain of mobile video. Live and delayed sharing seem to have their special characteristics, live video being used as a virtual window between places whereas delayed video usage has more scope for good-quality content. While this novel way of interacting via mobile video enables new social patterns, it also raises new concerns for privacy and trust between participating persons in all roles, largely due to the widely spreading possibilities of videos. Video in a social situation affects cameramen (who record), targets (who are recorded), passers-by (who are unintentionally in the situation), and the audience (who follow the videos or recording situations) but also the other way around, the participants affect the video by their varying and evolving personal and communicational motivations for recording.

The quality assurance program data analysis for diagnostic radiology in government hospitals in southern provinces of Syria

International Nuclear Information System (INIS)

Kharita, M. H.; Khedr, M. S.; Wannus, K. M.

2008-01-01

This study covered comprehensive evaluation for diagnostic radiography and fluorography equipment used in medicine by applying SAEC quality control rules. The results showed that most of considered x-ray equipment have an acceptable performance but few reached 21.6% in radiography and 36.8% in fluorography need repair and recalibration. Also recommendations and guidance for repair and preventative maintenance are required and quality assurance program should be applied in all diagnostic radiology institutions in Syria.(author)

Quality-of-Life Differences among Diagnostic Subgroups of Children Receiving Ventilating Tubes for Otitis Media.

Science.gov (United States)

Heidemann, Christian Hamilton; Lauridsen, Henrik Hein; Kjeldsen, Anette Drøhse; Faber, Christian Emil; Johansen, Eva Charlotte Jung; Godballe, Christian

2015-10-01

The pathological picture may differ considerably between diagnostic subgroups of children with otitis media receiving ventilating tubes. The aims of this study are to investigate differences in quality of life among diagnostic subgroups of children treated with ventilating tubes and to investigate possible predictors for clinical success. Longitudinal observational study. Secondary care units. Four hundred ninety-one families were enrolled in the study. The Otitis Media-6 questionnaire was applied in the assessment of child quality of life. Caregivers completed questionnaires at 7 time points from before treatment to 18-month follow-up. Logistic regression analysis was used to investigate possible predictors for clinical success. Response rates ranged from 96% to 81%; diagnostic distribution: 15% recurrent acute otitis media (rAOM), 47% otitis media with effusion (OME), and 38% mixed diagnosis of rAOM and OME (rAOM/OME). There were no significant differences between children diagnosed with rAOM and children diagnosed with rAOM/OME. However, these children had a significantly poorer quality of life at baseline compared with children diagnosed with only OME. Factors associated with clinical success included a diagnosis of rAOM, number of interrupted nights, physician visits, and canceled social activities due to OM. Results highlight the importance of distinguishing between diagnostic subgroups of children having ventilating tube treatment. A diagnosis of rAOM was found to predict baseline quality of life. Children with rAOM with or without OME were found to suffer significantly more than children with only OME before treatment. Factors associated with disease severity were found to predict clinical success. © American Academy of Otolaryngology-Head and Neck Surgery Foundation 2015.

Spatiotemporal video deinterlacing using control grid interpolation

Science.gov (United States)

Venkatesan, Ragav; Zwart, Christine M.; Frakes, David H.; Li, Baoxin

2015-03-01

With the advent of progressive format display and broadcast technologies, video deinterlacing has become an important video-processing technique. Numerous approaches exist in the literature to accomplish deinterlacing. While most earlier methods were simple linear filtering-based approaches, the emergence of faster computing technologies and even dedicated video-processing hardware in display units has allowed higher quality but also more computationally intense deinterlacing algorithms to become practical. Most modern approaches analyze motion and content in video to select different deinterlacing methods for various spatiotemporal regions. We introduce a family of deinterlacers that employs spectral residue to choose between and weight control grid interpolation based spatial and temporal deinterlacing methods. The proposed approaches perform better than the prior state-of-the-art based on peak signal-to-noise ratio, other visual quality metrics, and simple perception-based subjective evaluations conducted by human viewers. We further study the advantages of using soft and hard decision thresholds on the visual performance.

Comparison of Different Matrices as Potential Quality Control Samples for Neurochemical Dementia Diagnostics

NARCIS (Netherlands)

Lelental, Natalia; Brandner, Sebastian; Kofanova, Olga; Blennow, Kaj; Zetterberg, Henrik; Andreasson, Ulf; Engelborghs, Sebastiaan; Mroczko, Barbara; Gabryelewicz, Tomasz; Teunissen, Charlotte; Mollenhauer, Brit; Parnetti, Lucilla; Chiasserini, Davide; Molinuevo, Jose Luis; Perret-Liaudet, Armand; Verbeek, Marcel M.; Andreasen, Niels; Brosseron, Frederic; Bahl, Justyna M. C.; Herukka, Sanna-Kaisa; Hausner, Lucrezia; Froelich, Lutz; Labonte, Anne; Poirier, Judes; Miller, Anne-Marie; Zilka, Norbert; Kovacech, Branislav; Urbani, Andrea; Suardi, Silvia; Oliveira, Catarina; Baldeiras, Ines; Dubois, Bruno; Rot, Uros; Lehmann, Sylvain; Skinningsrud, Anders; Betsou, Fay; Wiltfang, Jens; Gkatzima, Olymbia; Winblad, Bengt; Buchfelder, Michael; Kornhuber, Johannes; Lewczuk, Piotr

2016-01-01

Background: Assay-vendor independent quality control (QC) samples for neurochemical dementia diagnostics (NDD) biomarkers are so far commercially unavailable. This requires that NDD laboratories prepare their own QC samples, for example by pooling leftover cerebrospinal fluid (CSF) samples.

Everything is ok on YouTube! Quality assessment of YouTube videos on the topic of phacoemulsification in eyes with small pupil.

Science.gov (United States)

Aykut, Aslan; Kukner, Amber Senel; Karasu, Bugra; Palancıglu, Yeliz; Atmaca, Fatih; Aydogan, Tumay

2018-01-22

Usage of YouTube as an educational tool is gaining attention in academic research. To date, there has been no study on the content and quality of eye surgery videos on YouTube. The aim of this study was to analyze YouTube videos on phacoemulsification in eyes with small pupil. We searched for the phrases "small pupil cataract surgery," "small pupil phacoemulsification," "small pupil cataract surgery complications," and "small pupil phacoemulsification complications" in January 2015. Each resulting video was evaluated by all authors, and Krippendorff's alpha was calculated to measure agreement. Videos were classified according to pupil size (small/very small) in the beginning of the surgery, and whether pupillary diameter was large enough to continue surgery safely after pupillary dilation by the surgeon in the video (safe/not safe). Methods of dilatation were also analyzed. Any stated ocular comorbidity or surgical complications were noted. A total of 96 videos were reviewed. No mechanical intervention for pupillary dilatation was performed in 46 videos. Fifty-eight operated eyes had no stated ocular comorbidity. Ninety-five operations ended successfully without major complication. There was fair agreement between the evaluators regarding pupil sizes (Kα = 0.670) but poor agreement regarding safety (Kα = 0.337). YouTube videos on small pupil phacoemulsification have low complication rates when compared to the literature, although no reliable mechanical dilatation methods are used in almost half of these videos. Until YouTube's place in e-learning becomes clearer, we suggest that viewers be cautious regarding small pupil phacoemulsification videos on YouTube.

An Analysis of Quality of Service (QoS In Live Video Streaming Using Evolved HSPA Network Media

Directory of Open Access Journals (Sweden)

Achmad Zakaria Azhar

2016-10-01

Full Text Available Evolved High Speed Packet Access (HSPA+ is a mobile telecommunication system technology and the evolution of HSPA technology. This technology has a packet data based service with downlink speeds up to 21.1 Mbps and uplink speed up to 11.5 Mbps on the bandwidth 5MHz. This technology is expected to fulfill and support the needs for information that involves all aspects of multimedia such as video and audio, especially live video streaming. By utilizing this technology it will facilitate communicating the information, for example to monitoring the situation of the house, the news coverage at some certain area, and other events in real time. This thesis aims to identify and test the Quality of Service (QoS performance on the network that is used for live video streaming with the parameters of throughput, delay, jitter and packet loss. The software used for monitoring the data traffic of the live video streaming network is wireshark network analyzer. From the test results it is obtained that the average throughput of provider B is 5,295 Kbps bigger than the provider A, the average delay of provider B is 0.618 ms smaller than the provider A, the average jitter of provider B is 0.420 ms smaller than the provider A and the average packet loss of provider B is 0.451% smaller than the provider A.

Delay Discounting of Video Game Players: Comparison of Time Duration Among Gamers.

Science.gov (United States)

Buono, Frank D; Sprong, Matthew E; Lloyd, Daniel P; Cutter, Christopher J; Printz, Destiny M B; Sullivan, Ryan M; Moore, Brent A

2017-02-01

Video game addiction or Internet game disorder, as proposed by the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition), has similar criterion characteristics to other impulse control disorders. There is limited research examining video game addiction within a behavioral economic framework using delay discounting. The current study evaluated delay-discounting patterns of money and video game play by usual weekly hours of video game play. A total of 104 participants were split into 1 of 3 groups of video game players (low, medium, and high) and were asked to complete a monetary and video game discounting procedure through an online survey. Results showed significant differences between groups within both the monetary (p = 0.003) and video game discounting procedures (p = 0.004). Additionally, a positive linear relationship was noted between the groups across both procedures. The results of the current article reinforce previous findings that more hours of video game use are associated with greater impulsivity and provide implications for future research.

The Educational Efficacy of Distinct Information Delivery Systems in Modified Video Games

Science.gov (United States)

Moshirnia, Andrew; Israel, Maya

2010-01-01

Despite the increasing popularity of many commercial video games, this popularity is not shared by educational video games. Modified video games, however, can bridge the gap in quality between commercial and education video games by embedding educational content into popular commercial video games. This study examined how different information…

Training value of laparoscopic colorectal videos on the World Wide Web: a pilot study on the educational quality of laparoscopic right hemicolectomy videos.

Science.gov (United States)

Celentano, V; Browning, M; Hitchins, C; Giglio, M C; Coleman, M G

2017-11-01

Instructive laparoscopy videos with appropriate exposition could be ideal for initial training in laparoscopic surgery, but unfortunately there are no guidelines for annotating these videos or agreed methods to measure the educational content and the safety of the procedure presented. Aim of this study is to systematically search the World Wide Web to determine the availability of laparoscopic colorectal surgery videos and to objectively establish their potential training value. A search for laparoscopic right hemicolectomy videos was performed on the three most used English language web search engines Google.com, Bing.com, and Yahoo.com; moreover, a survey among 25 local trainees was performed to identify additional websites for inclusion. All laparoscopic right hemicolectomy videos with an English language title were included. Videos of open surgery, single incision laparoscopic surgery, robotic, and hand-assisted surgery were excluded. The safety of the demonstrated procedure was assessed with a validated competency assessment tool specifically designed for laparoscopic colorectal surgery and data on the educational content of the video were extracted. Thirty-one websites were identified and 182 surgical videos were included. One hundred and seventy-three videos (95%) detailed the year of publication; this demonstrated a significant increase in the number of videos published per year from 2009. Characteristics of the patient were rarely presented, only 10 videos (5.4%) reported operating time and only 6 videos (3.2%) reported 30-day morbidity; 34 videos (18.6%) underwent a peer-review process prior to publication. Formal case presentation, the presence of audio narration, the use of diagrams, and snapshots and a step-by-step approach are all characteristics of peer-reviewed videos but no significant difference was found in the safety of the procedure. Laparoscopic videos can be a useful adjunct to operative training. There is a large and increasing amount of

Subjective evaluation of HDTV stereoscopic videos in IPTV scenarios using absolute category rating

Science.gov (United States)

Wang, K.; Barkowsky, M.; Cousseau, R.; Brunnström, K.; Olsson, R.; Le Callet, P.; Sjöström, M.

2011-03-01

Broadcasting of high definition (HD) stereobased 3D (S3D) TV are planned, or has already begun, in Europe, the US, and Japan. Specific data processing operations such as compression and temporal and spatial resampling are commonly used tools for saving network bandwidth when IPTV is the distribution form, as this results in more efficient recording and transmission of 3DTV signals, however at the same time it inevitably brings quality degradations to the processed video. This paper investigated observers quality judgments of state of the art video coding schemes (simulcast H.264/AVC or H.264/MVC), with or without added temporal and spatial resolution reduction of S3D videos, by subjective experiments using the Absolute Category Rating method (ACR) method. The results showed that a certain spatial resolution reduction working together with high quality video compressing was the most bandwidth efficient way of processing video data when the required video quality is to be judged as "good" quality. As the subjective experiment was performed in two different laboratories in two different countries in parallel, a detailed analysis of the interlab differences was performed.

Radiation exposure and image quality in x-Ray diagnostic radiology physical principles and clinical applications

CERN Document Server

Aichinger, Horst; Joite-Barfuß, Sigrid; Säbel, Manfred

2012-01-01

The largest contribution to radiation exposure to the population as a whole arises from diagnostic X-rays. Protecting the patient from radiation is a major aim of modern health policy, and an understanding of the relationship between radiation dose and image quality is of pivotal importance in optimising medical diagnostic radiology. In this volume the data provided for exploring these concerns are partly based on X-ray spectra, measured on diagnostic X-ray tube assemblies, and are supplemented by the results of measurements on phantoms and simulation calculations.

A reference guide to quality assurance for diagnostic radiography

International Nuclear Information System (INIS)

1986-01-01

The College of Radiographers, through its Professional and Technical Committee, set up a small Working Party to compile a list of references which would help radiographers to become experts at Quality Assurance in Diagnostic Imaging departments. The list is not comprehensive, but includes references which the Working Party have experience of and have found useful. The references provided should aid in the objectives of:- 1. determining acceptable standards of new equipment; 2. making comparisons during use with accepted base line performance; 3. establishing loss of cost effectiveness and the need for replacement. (author)

For Video Games, Bad News Is Good News: News Reporting of Violent Video Game Studies.

Science.gov (United States)

Copenhaver, Allen; Mitrofan, Oana; Ferguson, Christopher J

2017-12-01

News coverage of video game violence studies has been critiqued for focusing mainly on studies supporting negative effects and failing to report studies that did not find evidence for such effects. These concerns were tested in a sample of 68 published studies using child and adolescent samples. Contrary to our hypotheses, study effect size was not a predictor of either newspaper coverage or publication in journals with a high-impact factor. However, a relationship between poorer study quality and newspaper coverage approached significance. High-impact journals were not found to publish studies with higher quality. Poorer quality studies, which tended to highlight negative findings, also received more citations in scholarly sources. Our findings suggest that negative effects of violent video games exposure in children and adolescents, rather than large effect size or high methodological quality, increase the likelihood of a study being cited in other academic publications and subsequently receiving news media coverage.

The Use of Smart Glasses for Surgical Video Streaming.

Science.gov (United States)

Hiranaka, Takafumi; Nakanishi, Yuta; Fujishiro, Takaaki; Hida, Yuichi; Tsubosaka, Masanori; Shibata, Yosaku; Okimura, Kenjiro; Uemoto, Harunobu

2017-04-01

Observation of surgical procedures performed by experts is extremely important for acquisition and improvement of surgical skills. Smart glasses are small computers, which comprise a head-mounted monitor and video camera, and can be connected to the internet. They can be used for remote observation of surgeries by video streaming. Although Google Glass is the most commonly used smart glasses for medical purposes, it is still unavailable commercially and has some limitations. This article reports the use of a different type of smart glasses, InfoLinker, for surgical video streaming. InfoLinker has been commercially available in Japan for industrial purposes for more than 2 years. It is connected to a video server via wireless internet directly, and streaming video can be seen anywhere an internet connection is available. We have attempted live video streaming of knee arthroplasty operations that were viewed at several different locations, including foreign countries, on a common web browser. Although the quality of video images depended on the resolution and dynamic range of the video camera, speed of internet connection, and the wearer's attention to minimize image shaking, video streaming could be easily performed throughout the procedure. The wearer could confirm the quality of the video as the video was being shot by the head-mounted display. The time and cost for observation of surgical procedures can be reduced by InfoLinker, and further improvement of hardware as well as the wearer's video shooting technique is expected. We believe that this can be used in other medical settings.

Performance comparison of AV1, HEVC, and JVET video codecs on 360 (spherical) video

Science.gov (United States)

Topiwala, Pankaj; Dai, Wei; Krishnan, Madhu; Abbas, Adeel; Doshi, Sandeep; Newman, David

2017-09-01

This paper compares the coding efficiency performance on 360 videos, of three software codecs: (a) AV1 video codec from the Alliance for Open Media (AOM); (b) the HEVC Reference Software HM; and (c) the JVET JEM Reference SW. Note that 360 video is especially challenging content, in that one codes full res globally, but typically looks locally (in a viewport), which magnifies errors. These are tested in two different projection formats ERP and RSP, to check consistency. Performance is tabulated for 1-pass encoding on two fronts: (1) objective performance based on end-to-end (E2E) metrics such as SPSNR-NN, and WS-PSNR, currently developed in the JVET committee; and (2) informal subjective assessment of static viewports. Constant quality encoding is performed with all the three codecs for an unbiased comparison of the core coding tools. Our general conclusion is that under constant quality coding, AV1 underperforms HEVC, which underperforms JVET. We also test with rate control, where AV1 currently underperforms the open source X265 HEVC codec. Objective and visual evidence is provided.

Next generation diagnostic molecular pathology: critical appraisal of quality assurance in Europe.

Science.gov (United States)

Dubbink, Hendrikus J; Deans, Zandra C; Tops, Bastiaan B J; van Kemenade, Folkert J; Koljenović, S; van Krieken, Han J M; Blokx, Willeke A M; Dinjens, Winand N M; Groenen, Patricia J T A

2014-06-01

Tumor evaluation in pathology is more and more based on a combination of traditional histopathology and molecular analysis. Due to the rapid development of new cancer treatments that specifically target aberrant proteins present in tumor cells, treatment decisions are increasingly based on the molecular features of the tumor. Not only the number of patients eligible for targeted precision medicine, but also the number of molecular targets per patient and tumor type is rising. Diagnostic molecular pathology, the discipline that determines the molecular aberrations present in tumors for diagnostic, prognostic or predictive purposes, is faced with true challenges. The laboratories have to meet the need of comprehensive molecular testing using only limited amount of tumor tissue, mostly fixed in formalin and embedded in paraffin (FFPE), in short turnaround time. Choices must be made for analytical methods that provide accurate, reliable and cost-effective results. Validation of the test procedures and results is essential. In addition, participation and good performance in internal (IQA) and external quality assurance (EQA) schemes is mandatory. In this review, we critically evaluate the validation procedure for comprehensive molecular tests as well as the organization of quality assurance and assessment of competence of diagnostic molecular pathology laboratories within Europe. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

On the relative importance of audio and video in the presence of packet losses

DEFF Research Database (Denmark)

Korhonen, Jari; Reiter, Ulrich; Myakotnykh, Eugene

2010-01-01

In streaming applications, unequal protection of audio and video tracks may be necessary to maintain the optimal perceived overall quality. For this purpose, the application should be aware of the relative importance of audio and video in an audiovisual sequence. In this paper, we propose...... a subjective test arrangement for finding the optimal tradeoff between subjective audio and video qualities in situations when it is not possible to have perfect quality for both modalities concurrently. Our results show that content poses a significant impact on the preferred compromise between audio...... and video quality, but also that the currently used classification criteria for content are not sufficient to predict the users’ preference...

REAL-TIME VIDEO SCALING BASED ON CONVOLUTION NEURAL NETWORK ARCHITECTURE

OpenAIRE

S Safinaz; A V Ravi Kumar

2017-01-01

In recent years, video super resolution techniques becomes mandatory requirements to get high resolution videos. Many super resolution techniques researched but still video super resolution or scaling is a vital challenge. In this paper, we have presented a real-time video scaling based on convolution neural network architecture to eliminate the blurriness in the images and video frames and to provide better reconstruction quality while scaling of large datasets from lower resolution frames t...

A Directory of English Language Teaching Videos.

Science.gov (United States)

Falsetti, Julie, Comp.

This third edition of the video directory updates previous editions and alphabetically lists videos, by title. It is designed to assist in the teaching of English or the training of teachers of English. Information included are format, standard, variety, use, target, level, price, duration, quality, support materials included, distributor, year…

Markerless registration for image guided surgery. Preoperative image, intraoperative video image, and patient

International Nuclear Information System (INIS)

Kihara, Tomohiko; Tanaka, Yuko

1998-01-01

Real-time and volumetric acquisition of X-ray CT, MR, and SPECT is the latest trend of the medical imaging devices. A clinical challenge is to use these multi-modality volumetric information complementary on patient in the entire diagnostic and surgical processes. The intraoperative image and patient integration intents to establish a common reference frame by image in diagnostic and surgical processes. This provides a quantitative measure during surgery, for which we have been relied mostly on doctors' skills and experiences. The intraoperative image and patient integration involves various technologies, however, we think one of the most important elements is the development of markerless registration, which should be efficient and applicable to the preoperative multi-modality data sets, intraoperative image, and patient. We developed a registration system which integrates preoperative multi-modality images, intraoperative video image, and patient. It consists of a real-time registration of video camera for intraoperative use, a markerless surface sampling matching of patient and image, our previous works of markerless multi-modality image registration of X-ray CT, MR, and SPECT, and an image synthesis on video image. We think these techniques can be used in many applications which involve video camera like devices such as video camera, microscope, and image Intensifier. (author)

Real-time video streaming in mobile cloud over heterogeneous wireless networks

Science.gov (United States)

Abdallah-Saleh, Saleh; Wang, Qi; Grecos, Christos

2012-06-01

Recently, the concept of Mobile Cloud Computing (MCC) has been proposed to offload the resource requirements in computational capabilities, storage and security from mobile devices into the cloud. Internet video applications such as real-time streaming are expected to be ubiquitously deployed and supported over the cloud for mobile users, who typically encounter a range of wireless networks of diverse radio access technologies during their roaming. However, real-time video streaming for mobile cloud users across heterogeneous wireless networks presents multiple challenges. The network-layer quality of service (QoS) provision to support high-quality mobile video delivery in this demanding scenario remains an open research question, and this in turn affects the application-level visual quality and impedes mobile users' perceived quality of experience (QoE). In this paper, we devise a framework to support real-time video streaming in this new mobile video networking paradigm and evaluate the performance of the proposed framework empirically through a lab-based yet realistic testing platform. One particular issue we focus on is the effect of users' mobility on the QoS of video streaming over the cloud. We design and implement a hybrid platform comprising of a test-bed and an emulator, on which our concept of mobile cloud computing, video streaming and heterogeneous wireless networks are implemented and integrated to allow the testing of our framework. As representative heterogeneous wireless networks, the popular WLAN (Wi-Fi) and MAN (WiMAX) networks are incorporated in order to evaluate effects of handovers between these different radio access technologies. The H.264/AVC (Advanced Video Coding) standard is employed for real-time video streaming from a server to mobile users (client nodes) in the networks. Mobility support is introduced to enable continuous streaming experience for a mobile user across the heterogeneous wireless network. Real-time video stream packets

Interlaboratory comparison and accreditation in quality control testing of diagnostic X-ray equipment

International Nuclear Information System (INIS)

Kepler, K.; Vladimirov, A.; Servomaa, A.

2005-01-01

The Univ. of Tartu provides a quality control service to the majority of diagnostic X-ray departments in Estonia. Its methodology has been adopted from the IEC and other relevant standards. Recently the Testing Centre of the Univ. of Tartu was accredited on this methodology by ISO/IEC 17025. Besides the implementation of the quality management system, participation in interlaboratory comparison (ILC) was one of the prerequisites for the accreditation. Tests for estimating reproducibility of tube voltage and dose rate, accuracy of the voltage and accuracy of exposure time were carried out on a diagnostic X-ray unit in the Radiation and Nuclear Safety Authority in Helsinki. The measurement performance was judged by calculating deviation En normalised with respect to the stated uncertainties. En values for all tests were less than unity and by the common ILC criteria the testing performance could be considered as acceptable. (authors)

SDI HDTV video transmission unit; SDI high vision eizo denso sochi

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

The number is increasing of broadcasting stations who use HDTV (high-definition television) signals for program formulation for the improvement of video quality for general broadcasting programs. The above-named unit, which transmits HDTV signals which are broadcasting materials over a long distance with their high quality well preserved, is capable of the optical transmission of SDI (serial digital interface) signals meeting the standards of BTA (Broadcasting Technologies Association) on 1 video channel and 2 digital audio channels. It can also work on the light wavelength multiplex system. It was developed under the guidance of TTNet (Tokyo Telecommunication Network Co., Inc.), and gained public favor when it successfully transmitted programs over a distance of approximately 400km from Nagano to Tokyo during the Nagano Olympic Games. It now transmits various high-quality video signals for instance in the relay of baseball games, thereby contributing to the improvement of video quality for broadcasting. (translated by NEDO)

SVC VIDEO STREAM ALLOCATION AND ADAPTATION IN HETEROGENEOUS NETWORK

Directory of Open Access Journals (Sweden)

E. A. Pakulova

2016-07-01

Full Text Available The paper deals with video data transmission in format H.264/SVC standard with QoS requirements satisfaction. The Sender-Side Path Scheduling (SSPS algorithm and Sender-Side Video Adaptation (SSVA algorithm were developed. SSPS algorithm gives the possibility to allocate video traffic among several interfaces while SSVA algorithm dynamically changes the quality of video sequence in relation to QoS requirements. It was shown that common usage of two developed algorithms enables to aggregate throughput of access networks, increase parameters of Quality of Experience and decrease losses in comparison with Round Robin algorithm. For evaluation of proposed solution, the set-up was made. The trace files with throughput of existing public networks were used in experiments. Based on this information the throughputs of networks were limited and losses for paths were set. The results of research may be used for study and transmission of video data in heterogeneous wireless networks.

Secure and Efficient Reactive Video Surveillance for Patient Monitoring

Directory of Open Access Journals (Sweden)

An Braeken

2016-01-01

Full Text Available Video surveillance is widely deployed for many kinds of monitoring applications in healthcare and assisted living systems. Security and privacy are two promising factors that align the quality and validity of video surveillance systems with the caliber of patient monitoring applications. In this paper, we propose a symmetric key-based security framework for the reactive video surveillance of patients based on the inputs coming from data measured by a wireless body area network attached to the human body. Only authenticated patients are able to activate the video cameras, whereas the patient and authorized people can consult the video data. User and location privacy are at each moment guaranteed for the patient. A tradeoff between security and quality of service is defined in order to ensure that the surveillance system gets activated even in emergency situations. In addition, the solution includes resistance against tampering with the device on the patient’s side.

Diagnostic quality and observer variation in radiographic diagnoses of approximal caries

International Nuclear Information System (INIS)

Espelid, I.; Tveit, A.B.

1986-01-01

The aim of the study was to compare observer variations, observer strategy, and diagnostic quality with regard to radiographic caries diagnoses made at different depth levels. Qualitative assessment of approximal carious lesions on the basis of radiographs were made for sound (n=28) and carious (n=123) lesions by seven dentists. The inter- and intra-observer variations were lowest when lesions were diagnosed as being in the outermost parts of the teeth. The frequency of false positive scores was lower when dentin was examined as compared with enamel. The quality of radiographic diagnoses showed small variations (p>0.05) when different levels of pulpal depths were interpreted

Intelligent keyframe extraction for video printing

Science.gov (United States)

Zhang, Tong

2004-10-01

Nowadays most digital cameras have the functionality of taking short video clips, with the length of video ranging from several seconds to a couple of minutes. The purpose of this research is to develop an algorithm which extracts an optimal set of keyframes from each short video clip so that the user could obtain proper video frames to print out. In current video printing systems, keyframes are normally obtained by evenly sampling the video clip over time. Such an approach, however, may not reflect highlights or regions of interest in the video. Keyframes derived in this way may also be improper for video printing in terms of either content or image quality. In this paper, we present an intelligent keyframe extraction approach to derive an improved keyframe set by performing semantic analysis of the video content. For a video clip, a number of video and audio features are analyzed to first generate a candidate keyframe set. These features include accumulative color histogram and color layout differences, camera motion estimation, moving object tracking, face detection and audio event detection. Then, the candidate keyframes are clustered and evaluated to obtain a final keyframe set. The objective is to automatically generate a limited number of keyframes to show different views of the scene; to show different people and their actions in the scene; and to tell the story in the video shot. Moreover, frame extraction for video printing, which is a rather subjective problem, is considered in this work for the first time, and a semi-automatic approach is proposed.

Dynamic Video Streaming in Caching-enabled Wireless Mobile Networks

OpenAIRE

Liang, C.; Hu, S.

2017-01-01

Recent advances in software-defined mobile networks (SDMNs), in-network caching, and mobile edge computing (MEC) can have great effects on video services in next generation mobile networks. In this paper, we jointly consider SDMNs, in-network caching, and MEC to enhance the video service in next generation mobile networks. With the objective of maximizing the mean measurement of video quality, an optimization problem is formulated. Due to the coupling of video data rate, computing resource, a...

YouTube videos as a source of medical information during the Ebola hemorrhagic fever epidemic.

Science.gov (United States)

Nagpal, Sajan Jiv Singh; Karimianpour, Ahmadreza; Mukhija, Dhruvika; Mohan, Diwakar; Brateanu, Andrei

2015-01-01

The content and quality of medical information available on video sharing websites such as YouTube is not known. We analyzed the source and quality of medical information about Ebola hemorrhagic fever (EHF) disseminated on YouTube and the video characteristics that influence viewer behavior. An inquiry for the search term 'Ebola' was made on YouTube. The first 100 results were arranged in decreasing order of "relevance" using the default YouTube algorithm. Videos 1-50 and 51-100 were allocated to a high relevance (HR), and a low relevance (LR) video group, respectively. Multivariable logistic regression models were used to assess the predictors of a video being included in the HR vs. LR groups. Fourteen videos were excluded because they were parodies, songs or stand-up comedies (n = 11), not in English (n = 2) or a remaining part of a previous video (n = 1). Two scales, the video information and quality and index and the medical information and content index (MICI) assessed the overall quality, and the medical content of the videos, respectively. There were no videos from hospitals or academic medical centers. Videos in the HR group had a higher median number of views (186,705 vs. 43,796, p YouTube videos presenting clinical symptoms of infectious diseases during epidemics are more likely to be included in the HR group and influence viewers behavior.

Development of procedures to ensure quality and integrity in Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics systems

International Nuclear Information System (INIS)

Coutts, G.W.; Coon, M.L.; Hinz, A.F.; Hornady, R.S.; Lang, D.D.; Lund, N.P.

1983-01-01

The diagnostic systems for Tandem Mirror Experiment-Upgrade (TMX-U) have grown from eleven initial systems to more than twenty systems. During operation, diagnostic system modifications are sometimes required to complete experimental objectives. Also, during operations new diagnostic systems are being developed and implemented. To ensure and maintain the quality and integrity of the data signals, a set of plans and systematic actions are being developed. This paper reviews the procedures set in place to maintain the integrity of existing data systems and ensure the performance objectives of new diagnostics being added

Resolution enhancement of low quality videos using a high-resolution frame

NARCIS (Netherlands)

Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

2006-01-01

This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of

Pharyngeal video fluoroscopy: Selected unusual cases

International Nuclear Information System (INIS)

Conoley, P.M.; Fox, D.R.

1987-01-01

The videotape in this exhibit presents cases illustrative of the use of pharyngeal video fluoroscopy in diagnostic evaluations and therapeutic decision-making in a variety of speech and swallowing disorders of adults and children. Clinical problems addressed include an interesting compensatory speech mechanism in a cleft-palate patient, a preoperative candidate for a Lefort procedure, uncontrolled nasality in a singer, and dysphagia in an antimony worker

Video Inpainting of Complex Scenes

OpenAIRE

Newson, Alasdair; Almansa, Andrés; Fradet, Matthieu; Gousseau, Yann; Pérez, Patrick

2015-01-01

We propose an automatic video inpainting algorithm which relies on the optimisation of a global, patch-based functional. Our algorithm is able to deal with a variety of challenging situations which naturally arise in video inpainting, such as the correct reconstruction of dynamic textures, multiple moving objects and moving background. Furthermore, we achieve this in an order of magnitude less execution time with respect to the state-of-the-art. We are also able to achieve good quality result...

A qualitative analysis of methotrexate self-injection education videos on YouTube.

Science.gov (United States)

Rittberg, Rebekah; Dissanayake, Tharindri; Katz, Steven J

2016-05-01

The aim of this study is to identify and evaluate the quality of videos for patients available on YouTube for learning to self-administer subcutaneous methotrexate. Using the search term "Methotrexate injection," two clinical reviewers analyzed the first 60 videos on YouTube. Source and search rank of video, audience interaction, video duration, and time since video was uploaded on YouTube were recorded. Videos were classified as useful, misleading, or a personal patient view. Videos were rated for reliability, comprehensiveness, and global quality scale (GQS). Reasons for misleading videos were documented, and patient videos were documented as being either positive or negative towards methotrexate (MTX) injection. Fifty-one English videos overlapped between the two geographic locations; 10 videos were classified as useful (19.6 %), 14 misleading (27.5 %), and 27 personal patient view (52.9 %). Total views of videos were 161,028: 19.2 % useful, 72.8 % patient, and 8.0 % misleading. Mean GQS: 4.2 (±1.0) useful, 1.6 (±1.1) misleading, and 2.0 (±0.9) for patient videos (p tool available, clinicians need to be familiar with specific resources to help guide and educate their patients to ensure best outcomes.

Video error concealment using block matching and frequency selective extrapolation algorithms

Science.gov (United States)

P. K., Rajani; Khaparde, Arti

2017-06-01

Error Concealment (EC) is a technique at the decoder side to hide the transmission errors. It is done by analyzing the spatial or temporal information from available video frames. It is very important to recover distorted video because they are used for various applications such as video-telephone, video-conference, TV, DVD, internet video streaming, video games etc .Retransmission-based and resilient-based methods, are also used for error removal. But these methods add delay and redundant data. So error concealment is the best option for error hiding. In this paper, the error concealment methods such as Block Matching error concealment algorithm is compared with Frequency Selective Extrapolation algorithm. Both the works are based on concealment of manually error video frames as input. The parameter used for objective quality measurement was PSNR (Peak Signal to Noise Ratio) and SSIM(Structural Similarity Index). The original video frames along with error video frames are compared with both the Error concealment algorithms. According to simulation results, Frequency Selective Extrapolation is showing better quality measures such as 48% improved PSNR and 94% increased SSIM than Block Matching Algorithm.

Reduced bandwidth video for remote vehicle operations

Energy Technology Data Exchange (ETDEWEB)

Noell, T.E.; DePiero, F.W.

1993-08-01

Oak Ridge National Laboratory staff have developed a video compression system for low-bandwidth remote operations. The objective is to provide real-time video at data rates comparable to available tactical radio links, typically 16 to 64 thousand bits per second (kbps), while maintaining sufficient quality to achieve mission objectives. The system supports both continuous lossy transmission of black and white (gray scale) video for remote driving and progressive lossless transmission of black and white images for remote automatic target acquisition. The average data rate of the resulting bit stream is 64 kbps. This system has been demonstrated to provide video of sufficient quality to allow remote driving of a High-Mobility Multipurpose Wheeled Vehicle at speeds up to 15 mph (24.1 kph) on a moguled dirt track. The nominal driving configuration provides a frame rate of 4 Hz, a compression per frame of 125:1, and a resulting latency of {approximately}1s. This paper reviews the system approach and implementation, and further describes some of our experiences when using the system to support remote driving.

Re-Establishment of Standard Radiation Qualities for Calibration of Dosemeter in Diagnostic Radiology - RQR Series

International Nuclear Information System (INIS)

Asmaliza Hashim; Norhayati Abdullah; Mohd Firdaus Abd Rahman

2016-01-01

After repairing the high voltage (HV) generator for Philips MG165 X-Ray Machine, the reestablishment of the standard radiation qualities has been done at Medical Physics Calibration Laboratory to meet the IEC and IAEA standard. Standard radiation qualities are the important criteria for calibration of dosemeter in diagnostic radiology. Standard radiation qualities are defined as the added filtration needed to produce and the half value layer (HVL) of the beam for specifies x-ray tube kilo voltage (kV). For calibration of dosemeter in diagnostic radiology, standard radiation qualities RQR represent the beam incident on the patient in general radiography, fluoroscopy and dental application. The HVL were measured using PTW ion chamber of volume 1 cm"3 with PTW electrometer and aluminium filter with 99.9 % purity was used as additional filter for RQR and filter for HVL. The first establishment of standard radiation qualities was made in 2009 for the radiation qualities of RQR. The results of additional filter and 1st HVL from 2009 to 2016 will be discussed further in paper. The ratios of the measured HVL to the standard IEC HVL value for the RQR series also described in this paper. The details of the measurement and the results are described in this paper. (author)

Role of the medical physicist in quality control in diagnostic x-ray departments

International Nuclear Information System (INIS)

Cameron, J.R.

1973-01-01

Medical physicists can play a role in education of future radiologists and technologists by teaching quality control needs and techniques. He or she can also provide service to the diagnostic section by establishing a quality control program. Finally, the medical physicist can play an important role in the development of simple and inexpensive techniques for quality control by radiological technologists. The ongoing work at the University of Wisconsin in this area is to provide quality control in measurement of the effective kVcp, the measurement of the effective focal spot size, the performance of the processing equipment, the output in mR/mAs, and the measurement of the half-value-layer and the total filtration. (U.S.)

Fast and Accurate Video PQoS Estimation over Wireless Networks

Directory of Open Access Journals (Sweden)

Emanuele Viterbo

2008-06-01

Full Text Available This paper proposes a curve fitting technique for fast and accurate estimation of the perceived quality of streaming media contents, delivered within a wireless network. The model accounts for the effects of various network parameters such as congestion, radio link power, and video transmission bit rate. The evaluation of the perceived quality of service (PQoS is based on the well-known VQM objective metric, a powerful technique which is highly correlated to the more expensive and time consuming subjective metrics. Currently, PQoS is used only for offline analysis after delivery of the entire video content. Thanks to the proposed simple model, we can estimate in real time the video PQoS and we can rapidly adapt the content transmission through scalable video coding and bit rates in order to offer the best perceived quality to the end users. The designed model has been validated through many different measurements in realistic wireless environments using an ad hoc WiFi test bed.

The Important Elements of a Science Video

Science.gov (United States)

Harned, D. A.; Moorman, M.; McMahon, G.

2012-12-01

New technologies have revolutionized use of video as a means of communication. Films have become easier to create and to distribute. Video is omnipresent in our culture and supplements or even replaces writing in many applications. How can scientists and educators best use video to communicate scientific results? Video podcasts are being used in addition to journal, print, and online publications to communicate the relevance of scientific findings of the U.S. Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) program to general audiences such as resource managers, educational groups, public officials, and the general public. In an effort to improve the production of science videos a survey was developed to provide insight into effective science communication with video. Viewers of USGS podcast videos were surveyed using Likert response- scaling to identify the important elements of science videos. The surveys were of 120 scientists and educators attending the 2010 and 2011 Fall Meetings of the American Geophysical Union and the 2012 meeting of the National Monitoring Council. The median age of the respondents was 44 years, with an education level of a Bachelor's Degree or higher. Respondents reported that their primary sources for watching science videos were YouTube and science websites. Video length was the single most important element associated with reaching the greatest number of viewers. The surveys indicated a median length of 5 minutes as appropriate for a web video, with 5-7 minutes the 25th-75th percentiles. An illustration of the effect of length: a 5-minute and a 20-minute version of a USGS film on the effect of urbanization on water-quality was made available on the same website. The short film has been downloaded 3 times more frequently than the longer film version. The survey showed that the most important elements to include in a science film are style elements including strong visuals, an engaging story, and a simple message, and

Smart Video Communication for Social Groups - The Vconect Project

NARCIS (Netherlands)

M. Ursu; P. Stollenmayer; D. Williams; P. Torres; P.S. Cesar Garcia (Pablo Santiago); N. Farber; E. Geelhoed

2014-01-01

htmlabstractThis article introduces the Vconect project. Vconect (Video Communications for Networked Communities) is a collaborative European research and development project dealing with high-quality enriched video as a medium for mass communication within social communities. The technical

Impact of different cloud deployments on real-time video applications for mobile video cloud users

Science.gov (United States)

Khan, Kashif A.; Wang, Qi; Luo, Chunbo; Wang, Xinheng; Grecos, Christos

2015-02-01

The latest trend to access mobile cloud services through wireless network connectivity has amplified globally among both entrepreneurs and home end users. Although existing public cloud service vendors such as Google, Microsoft Azure etc. are providing on-demand cloud services with affordable cost for mobile users, there are still a number of challenges to achieve high-quality mobile cloud based video applications, especially due to the bandwidth-constrained and errorprone mobile network connectivity, which is the communication bottleneck for end-to-end video delivery. In addition, existing accessible clouds networking architectures are different in term of their implementation, services, resources, storage, pricing, support and so on, and these differences have varied impact on the performance of cloud-based real-time video applications. Nevertheless, these challenges and impacts have not been thoroughly investigated in the literature. In our previous work, we have implemented a mobile cloud network model that integrates localized and decentralized cloudlets (mini-clouds) and wireless mesh networks. In this paper, we deploy a real-time framework consisting of various existing Internet cloud networking architectures (Google Cloud, Microsoft Azure and Eucalyptus Cloud) and a cloudlet based on Ubuntu Enterprise Cloud over wireless mesh networking technology for mobile cloud end users. It is noted that the increasing trend to access real-time video streaming over HTTP/HTTPS is gaining popularity among both research and industrial communities to leverage the existing web services and HTTP infrastructure in the Internet. To study the performance under different deployments using different public and private cloud service providers, we employ real-time video streaming over the HTTP/HTTPS standard, and conduct experimental evaluation and in-depth comparative analysis of the impact of different deployments on the quality of service for mobile video cloud users. Empirical

Video Waterscrambling: Towards a Video Protection Scheme Based on the Disturbance of Motion Vectors

Science.gov (United States)

Bodo, Yann; Laurent, Nathalie; Laurent, Christophe; Dugelay, Jean-Luc

2004-12-01

With the popularity of high-bandwidth modems and peer-to-peer networks, the contents of videos must be highly protected from piracy. Traditionally, the models utilized to protect this kind of content are scrambling and watermarking. While the former protects the content against eavesdropping (a priori protection), the latter aims at providing a protection against illegal mass distribution (a posteriori protection). Today, researchers agree that both models must be used conjointly to reach a sufficient level of security. However, scrambling works generally by encryption resulting in an unintelligible content for the end-user. At the moment, some applications (such as e-commerce) may require a slight degradation of content so that the user has an idea of the content before buying it. In this paper, we propose a new video protection model, called waterscrambling, whose aim is to give such a quality degradation-based security model. This model works in the compressed domain and disturbs the motion vectors, degrading the video quality. It also allows embedding of a classical invisible watermark enabling protection against mass distribution. In fact, our model can be seen as an intermediary solution to scrambling and watermarking.

Video Waterscrambling: Towards a Video Protection Scheme Based on the Disturbance of Motion Vectors

Directory of Open Access Journals (Sweden)

Yann Bodo

2004-10-01

Full Text Available With the popularity of high-bandwidth modems and peer-to-peer networks, the contents of videos must be highly protected from piracy. Traditionally, the models utilized to protect this kind of content are scrambling and watermarking. While the former protects the content against eavesdropping (a priori protection, the latter aims at providing a protection against illegal mass distribution (a posteriori protection. Today, researchers agree that both models must be used conjointly to reach a sufficient level of security. However, scrambling works generally by encryption resulting in an unintelligible content for the end-user. At the moment, some applications (such as e-commerce may require a slight degradation of content so that the user has an idea of the content before buying it. In this paper, we propose a new video protection model, called waterscrambling, whose aim is to give such a quality degradation-based security model. This model works in the compressed domain and disturbs the motion vectors, degrading the video quality. It also allows embedding of a classical invisible watermark enabling protection against mass distribution. In fact, our model can be seen as an intermediary solution to scrambling and watermarking.

EDICAM fast video diagnostic installation on the COMPASS tokamak

International Nuclear Information System (INIS)

Szappanos, A.; Berta, M.; Hron, M.; Panek, R.; Stoeckel, J.; Tulipan, S.; Veres, G.; Weinzettl, V.; Zoletnik, S.

2010-01-01

A new camera system 'event detection intelligent camera' (EDICAM) is being developed by the Hungarian Association and has been installed on the COMPASS tokamak in the Institute of Plasma Physics AS CR in Prague, during February 2009. The standalone system contains a data acquisition PC and a prototype sensor module of EDICAM. Appropriate optical system have been designed and adjusted for the local requirements, and a mechanical holder keeps the camera out of the magnetic field. The fast camera contains a monochrome CMOS sensor with advanced control features and spectral sensitivity in the visible range. A special web based control interface has been implemented using Java spring framework to provide the control features in a graphical user environment. Java native interface (JNI) is used to reach the driver functions and to collect the data stored by direct memory access (DMA). Using a built in real-time streaming server one can see the live video from the camera through any web browser in the intranet. The live video is distributed in a Motion Jpeg format using real-time streaming protocol (RTSP) and a Java applet have been written to show the movie on the client side. The control system contains basic image processing features and the 3D wireframe of the tokamak can be projected to the selected frames. A MatLab interface is also presented with advanced post processing and analysis features to make the raw data available for high level computing programs. In this contribution all the concepts of EDICAM control center and the functions of the distinct software modules are described.

Quality control of diagnostic radiology to reduce absorbed dose of patients in Iran

International Nuclear Information System (INIS)

Aghahadi, Bahman.

1996-01-01

In order to reduce absorbed dose, to increase the image quality and to reduce the numbers of rejected films various quality control parameters were applied to X ray machines. These parameter are Kilo Volt peak, Milli Ampere, Exposure Time Focal Film Distance, Inherent Filters, Additional Filters Half Value Layer, Processor Condition, Cassettes. To evaluate and to apply these parameters in diagnostic radiological centers, ten hospitals were selected and a total number of 12 X ray machines were kept under quality control program. Considering different kinds of diagnostic radiology examination and to compare the dose before and after implementation of a quality control program, two kinds of examinations include in chest and abdomen examinations were considered. For each X ray machine, ten patients and for all selected centers, 120 patients were selected for chest examination and 120 patients for abdomen examinations; before and after implementation of quality control program, a total of 480 patients were selected randomly to be controlled. Base on different examinations carried out, it was concluded that both exposure conditions and general situations in radiological centers were not acceptable. The dosimetry results show that the average ski dose for chest and abdomen examinations were 0.28 m Gy and 4.23 Gy respectively. Before implementation of quality control step to reduce the surface skin dose, quality control parameters were applied and the exposure conditions were imposed. On average the absorbed doses for chest and abdomen examination were decreased to 79% and 61% respectively after the implementation of the program. From dose reduction point of view, the results of a part of this project which made by co-operation of International Atomic Energy Agency showed that Iran acquired the first grade for chest examination and second grade for abdomen examination. Base on the results obtained, the number of patients under chest and abdomen examination were 4041588 and

Diagnostic image quality of mammograms in German outpatient medical care

International Nuclear Information System (INIS)

Pfandzelter, R.; Wuelfing, U.; Boedeker, B.

2010-01-01

Purpose: A total of 79 115 mammograms from statutory health insurance (SHI) physicians within German outpatient care were evaluated with respect to the diagnostic image quality. Materials and Methods: Mammograms were randomly selected between 2006 and 2008 by the regional Associations of Statutory Health Insurance Physicians and submitted to regional boards of experts for external evaluation. The mammogram quality was evaluated using a 3-point scale (adequate, borderline, failure) and documented using a nationally standardized protocol. Results: 87.6 % of the mammograms were classified as adequate, 11.0 % as borderline and 1.4 % as failure. Mediolateral oblique mammograms (mlo) had worse ratings than craniocaudal mammograms (cc). Main reasons for classifying the mammograms as borderline or failure were 'inframammary fold not adequately visualized' (mlo), 'pectoral muscle not in the correct angle or not to the level with the nipple' (mlo), 'the nipple not in profile' (mlo, cc) and 'breast not completely or not adequately visualized' (cc). Conclusion: The results show a good overall quality of mammograms in German outpatient medical care. Failures can be associated predominantly with incorrect positioning of the breast. More precisely defined quality criteria using objective measures are recommended, especially for craniocaudal mammograms (cc). (orig.)

CD-ROM training course in quality assurance in diagnostic imaging

International Nuclear Information System (INIS)

Khoury, H.J.; Machado, P.; Drexler, G.

2001-01-01

This paper discusses the CD-ROM elaborated to provide a continuous professional formation and a practical guidance on the implementation and operation of routine quality assurance (QA) programme for medical physicists, regulator authorities and for those personnel concerned with the daily provision of diagnostic radiology services. The CD-ROM contains topics on the basic concepts of QA in radiodiagnostic, and it also allows the user to visualise effects on the variation of technical parameters (tube potential (kV) and current (mA), filtration) in the quality of the image. This possibility will contribute to the better understanding of the phenomena associated with the quality of the image. Besides, the program contains the procedures for the execution of the tests of the equipment and the route of implantation of program of quality assurance. It is interactive with the user, it fills a gap in the medical physics area and it allows the student's continuous formation because it assists the beginner, with the basic concepts, and the professional, with the aid in the implantation of the program of QA. The presentation is in the Portuguese language. (author)

Development, evaluation and implementation of video-EEG telemetry at home.

Science.gov (United States)

Brunnhuber, Franz; Amin, Devyani; Nguyen, Yan; Goyal, Sushma; Richardson, Mark P

2014-05-01

To describe the development and implementation of video EEG telemetry (VT) in the patient's home (home video telemetry, HVT) in a single centre. HVT met the UK Medical Research Council definition of a complex intervention, and we used its guidance to evaluate the process of piloting, evaluating, developing and implementing this new clinical service. The first phase was a feasibility study, comparing inpatient VT (IVT) with HVT in a test-retest design (n=5), to assess data quality and yield of clinically relevant events. The second phase was a pre-implementation study (n=8), to examine acceptability and satisfaction as well as the costs of IVT and HVT. Subsequently, we implemented the service, and reviewed the outcomes of the first 34 patients. The feasibility study found no difference in the quality of recording or clinical yield between IVT and HVT. The pre-implementation study showed excellent patient satisfaction. We also discuss the findings of the main stakeholder survey (consultants and technicians). Our economic modelling demonstrates a clear financial superiority of HVT over IVT. Our findings show that diagnostic HVT for seizure classification and polysomnographies can be carried out safely in the patients' home and poses no security risks for staff. HVT can be effectively integrated into an existing tertiary care service as a routine home or community-based procedure. We hope to encourage other clinical neurophysiology departments and epilepsy centres to take advantage of our experience and consider adopting and implementing HVT, with the aim of a nationwide coverage. Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

A comparative study of quality control in diagnostic radiology

International Nuclear Information System (INIS)

Kharita, M. H.; Khedr, M.S.; Wannus, K.M.

2008-01-01

The main objective of this comparative study was to evaluate the national quality assurance program for X-ray diagnostic radiology in Syrian governmental hospitals. Two periods were covered in this study, the first period was from 1986 to 1998 (52 hospitals and 149 X-ray machines were considered) and the second period from 1999 to 2005 (41 hospitals and 95 X-ray machines were considered). Most of the X-ray machines studied were within the acceptable performance, but few machines needed recalibration for some parameters. Considerable improvement of about 50% was reported in the second period. This improvement could be attributed to the establishment of an effective National Regulatory Authority in Syria in 1998 that introduced and gradually enforced the quality assurance requirement for X-ray equipment as part of the licensing process and to the relatively newer X-ray machines covered in the second period. The Author 2008. Published by Oxford Univ. Press. All rights reserved. (authors)

[THE VIRTUAL CYTOLOGIC SLIDES FOR EXTERNAL EVALUATION OF QUALITY OF IMPLEMENTATION OF CYTOLOGIC ANALYSES IN CLINICAL DIAGNOSTIC LABORATORIES: POSSIBILITIES AND PERSPECTIVES].

Science.gov (United States)

Djangirova, T V; Shabalova, I P; Pronichev, A N; Polyakov, E V

2015-08-01

The article considers application of technology of analysis of cytological slides in external quality control of clinical diagnostic laboratories. The advantages of virtual slides are demonstrated against other applied technologies of external evaluation of quality i.e. slide plate and digital micro-photography. The conditions of formation of virtual slides for external evaluation of quality of clinical diagnostic laboratories. The technology of their application is described. The success of practical application of considered technology in the Federal system of external evaluation of quality is emphasized.

Laboratory diagnostic methods, system of quality and validation

Directory of Open Access Journals (Sweden)

Ašanin Ružica

2005-01-01

Full Text Available It is known that laboratory investigations secure safe and reliable results that provide a final confirmation of the quality of work. Ideas, planning, knowledge, skills, experience, and environment, along with good laboratory practice, quality control and reliability of quality, make the area of biological investigations very complex. In recent years, quality control, including the control of work in the laboratory, is based on international standards and is used at that level. The implementation of widely recognized international standards, such as the International Standard ISO/IEC 17025 (1 and the implementing of the quality system series ISO/IEC 9000 (2 have become the imperative on the grounds of which laboratories have a formal, visible and corresponding system of quality. The diagnostic methods that are used must constantly yield results which identify the animal as positive or negative, and the precise status of the animal is determined with a predefined degree of statistical significance. Methods applied on a selected population reduce the risk of obtaining falsely positive or falsely negative results. A condition for this are well conceived and documented methods, with the application of the corresponding reagents, and work with professional and skilled staff. This process requires also a consistent implementation of the most rigorous experimental plans, epidemiological and statistical data and estimations, with constant monitoring of the validity of the applied methods. Such an approach is necessary in order to cut down the number of misconceptions and accidental mistakes, for a referent population of animals on which the validity of a method is tested. Once a valid method is included in daily routine investigations, it is necessary to apply constant monitoring for the purpose of internal quality control, in order adequately to evaluate its reproducibility and reliability. Consequently, it is necessary at least twice yearly to conduct

How and when do expert emergency physicians generate and evaluate diagnostic hypotheses? A qualitative study using head-mounted video cued-recall interviews.

Science.gov (United States)

Pelaccia, Thierry; Tardif, Jacques; Triby, Emmanuel; Ammirati, Christine; Bertrand, Catherine; Dory, Valérie; Charlin, Bernard

2014-12-01

The ability to make a diagnosis is a crucial skill in emergency medicine. Little is known about the way emergency physicians reach a diagnosis. This study aims to identify how and when, during the initial patient examination, emergency physicians generate and evaluate diagnostic hypotheses. We carried out a qualitative research project based on semistructured interviews with emergency physicians. The interviews concerned management of an emergency situation during routine medical practice. They were associated with viewing the video recording of emergency situations filmed in an "own-point-of-view" perspective. The emergency physicians generated an average of 5 diagnostic hypotheses. Most of these hypotheses were generated before meeting the patient or within the first 5 minutes of the meeting. The hypotheses were then rank ordered within the context of a verification procedure based on identifying key information. These tasks were usually accomplished without conscious effort. No hypothesis was completely confirmed or refuted until the results of investigations were available. The generation and rank ordering of diagnostic hypotheses is based on the activation of cognitive processes, enabling expert emergency physicians to process environmental information and link it to past experiences. The physicians seemed to strive to avoid the risk of error by remaining aware of the possibility of alternative hypotheses as long as they did not have the results of investigations. Understanding the diagnostic process used by emergency physicians provides interesting ideas for training residents in a specialty in which the prevalence of reasoning errors leading to incorrect diagnoses is high. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Video Tutorial of Continental Food

Science.gov (United States)

Nurani, A. S.; Juwaedah, A.; Mahmudatussa'adah, A.

2018-02-01

This research is motivated by the belief in the importance of media in a learning process. Media as an intermediary serves to focus on the attention of learners. Selection of appropriate learning media is very influential on the success of the delivery of information itself both in terms of cognitive, affective and skills. Continental food is a course that studies food that comes from Europe and is very complex. To reduce verbalism and provide more real learning, then the tutorial media is needed. Media tutorials that are audio visual can provide a more concrete learning experience. The purpose of this research is to develop tutorial media in the form of video. The method used is the development method with the stages of analyzing the learning objectives, creating a story board, validating the story board, revising the story board and making video tutorial media. The results show that the making of storyboards should be very thorough, and detailed in accordance with the learning objectives to reduce errors in video capture so as to save time, cost and effort. In video capturing, lighting, shooting angles, and soundproofing make an excellent contribution to the quality of tutorial video produced. In shooting should focus more on tools, materials, and processing. Video tutorials should be interactive and two-way.

YouTube Videos on Botulinum Toxin A for Wrinkles: A Useful Resource for Patient Education.

Science.gov (United States)

Wong, Katharine; Doong, Judy; Trang, Trinh; Joo, Sarah; Chien, Anna L

2017-12-01

Patients interested in botulinum toxin type A (BTX-A) for wrinkles search for videos on YouTube, but little is known about the quality and reliability of the content. The authors examined the quality, reliability, content, and target audience of YouTube videos on BTX for wrinkles. In this cross-sectional study, the term "Botox" was searched on YouTube. Sixty relevant videos in English were independently categorized by 2 reviewers as useful informational, misleading informational, useful patient view, or misleading patient view. Disagreements were settled by a third reviewer. Videos were rated on the Global Quality Scale (GQS) (1 = poor, 5 = excellent). Sixty-three percent of the BTX YouTube videos were useful informational (GQS = 4.4 ± 0.7), 33% as useful patient view (GQS = 3.21 ± 1.2), 2% as misleading informational (GQS = 1), and 2% as misleading patient view (GQS = 2.5). The large number of useful videos, high reliability, and the wide range of content covered suggests that those who search for antiwrinkle BTX videos on YouTube are likely to view high-quality content. This suggests that YouTube may be a good source of videos to recommend for patients interested in BTX.

Performance Evaluation and Parameter Optimization of SoftCast Wireless Video Broadcast

Directory of Open Access Journals (Sweden)

Dongxue Yang

2015-08-01

Full Text Available Wireless video broadcast plays an imp ortant role in multimedia communication with the emergence of mobile video applications. However, conventional video broadcast designs suffer from a cliff effect due to separated source and channel encoding. The newly prop osed SoftCast scheme employs a cross-layer design, whose reconstructed video quality is prop ortional to the channel condition. In this pap er, we provide the p erformance evaluation and the parameter optimization of the SoftCast system. Optimization principles on parameter selection are suggested to obtain a b etter video quality, o ccupy less bandwidth and/or utilize lower complexity. In addition, we compare SoftCast with H.264 in the LTE EPA scenario. The simulation results show that SoftCast provides a b etter p erformance in the scalability to channel conditions and the robustness to packet losses.

Hierarchical resource allocation for robust in-home video streaming

NARCIS (Netherlands)

Stok, van der P.D.V.; Jarnikov, D.; Kozlov, S.; Hartskamp, van M.A.; Lukkien, J.J.

2007-01-01

High quality video streaming puts high demands on network and processor resources. The bandwidth of the communication medium and the timely arrival of the frames necessitate a tight resource allocation. Given the dynamic environment where videos are started and stopped and electro-magnetic

Background-Modeling-Based Adaptive Prediction for Surveillance Video Coding.

Science.gov (United States)

Zhang, Xianguo; Huang, Tiejun; Tian, Yonghong; Gao, Wen

2014-02-01

The exponential growth of surveillance videos presents an unprecedented challenge for high-efficiency surveillance video coding technology. Compared with the existing coding standards that were basically developed for generic videos, surveillance video coding should be designed to make the best use of the special characteristics of surveillance videos (e.g., relative static background). To do so, this paper first conducts two analyses on how to improve the background and foreground prediction efficiencies in surveillance video coding. Following the analysis results, we propose a background-modeling-based adaptive prediction (BMAP) method. In this method, all blocks to be encoded are firstly classified into three categories. Then, according to the category of each block, two novel inter predictions are selectively utilized, namely, the background reference prediction (BRP) that uses the background modeled from the original input frames as the long-term reference and the background difference prediction (BDP) that predicts the current data in the background difference domain. For background blocks, the BRP can effectively improve the prediction efficiency using the higher quality background as the reference; whereas for foreground-background-hybrid blocks, the BDP can provide a better reference after subtracting its background pixels. Experimental results show that the BMAP can achieve at least twice the compression ratio on surveillance videos as AVC (MPEG-4 Advanced Video Coding) high profile, yet with a slightly additional encoding complexity. Moreover, for the foreground coding performance, which is crucial to the subjective quality of moving objects in surveillance videos, BMAP also obtains remarkable gains over several state-of-the-art methods.

Digital video for the desktop

CERN Document Server

Pender, Ken

1999-01-01

Practical introduction to creating and editing high quality video on the desktop. Using examples from a variety of video applications, benefit from a professional's experience, step-by-step, through a series of workshops demonstrating a wide variety of techniques. These include producing short films, multimedia and internet presentations, animated graphics and special effects.The opportunities for the independent videomaker have never been greater - make sure you bring your understanding fully up to date with this invaluable guide.No prior knowledge of the technology is assumed, with explanati

Statistical analysis of subjective preferences for video enhancement

Science.gov (United States)

Woods, Russell L.; Satgunam, PremNandhini; Bronstad, P. Matthew; Peli, Eli

2010-02-01

Measuring preferences for moving video quality is harder than for static images due to the fleeting and variable nature of moving video. Subjective preferences for image quality can be tested by observers indicating their preference for one image over another. Such pairwise comparisons can be analyzed using Thurstone scaling (Farrell, 1999). Thurstone (1927) scaling is widely used in applied psychology, marketing, food tasting and advertising research. Thurstone analysis constructs an arbitrary perceptual scale for the items that are compared (e.g. enhancement levels). However, Thurstone scaling does not determine the statistical significance of the differences between items on that perceptual scale. Recent papers have provided inferential statistical methods that produce an outcome similar to Thurstone scaling (Lipovetsky and Conklin, 2004). Here, we demonstrate that binary logistic regression can analyze preferences for enhanced video.

Error Resilient Video Compression Using Behavior Models

Directory of Open Access Journals (Sweden)

Jacco R. Taal

2004-03-01

Full Text Available Wireless and Internet video applications are inherently subjected to bit errors and packet errors, respectively. This is especially so if constraints on the end-to-end compression and transmission latencies are imposed. Therefore, it is necessary to develop methods to optimize the video compression parameters and the rate allocation of these applications that take into account residual channel bit errors. In this paper, we study the behavior of a predictive (interframe video encoder and model the encoders behavior using only the statistics of the original input data and of the underlying channel prone to bit errors. The resulting data-driven behavior models are then used to carry out group-of-pictures partitioning and to control the rate of the video encoder in such a way that the overall quality of the decoded video with compression and channel errors is optimized.

Presentation of 3D Scenes Through Video Example.

Science.gov (United States)

Baldacci, Andrea; Ganovelli, Fabio; Corsini, Massimiliano; Scopigno, Roberto

2017-09-01

Using synthetic videos to present a 3D scene is a common requirement for architects, designers, engineers or Cultural Heritage professionals however it is usually time consuming and, in order to obtain high quality results, the support of a film maker/computer animation expert is necessary. We introduce an alternative approach that takes the 3D scene of interest and an example video as input, and automatically produces a video of the input scene that resembles the given video example. In other words, our algorithm allows the user to "replicate" an existing video, on a different 3D scene. We build on the intuition that a video sequence of a static environment is strongly characterized by its optical flow, or, in other words, that two videos are similar if their optical flows are similar. We therefore recast the problem as producing a video of the input scene whose optical flow is similar to the optical flow of the input video. Our intuition is supported by a user-study specifically designed to verify this statement. We have successfully tested our approach on several scenes and input videos, some of which are reported in the accompanying material of this paper.

Health-related quality of life, anxiety and depression in the diagnostic phase of suspected cancer, and the influence of diagnosis

DEFF Research Database (Denmark)

Larsen, Ellen Frøsig Moseholm; Rydahl Hansen, Susan; Overgaard, Dorthe

2016-01-01

suspected to have cancer based on non-specific symptoms was performed. Participants completed the EORTC-QLQ-C30 quality of life scale, HADS, SOC-13 and self-rated health before and after completing diagnostic evaluations. Intra- and inter-group differences between patients diagnosed with cancer versus......-specific symptoms experience a high prevalence of anxiety and affected quality of life prior to knowledge of the diagnosis. The predictive value of the baseline scores is important when assessing the psychological impact of undergoing diagnostic evaluations for cancer.......Background Undergoing diagnostic evaluation for cancer has been associated with a high prevalence of anxiety and depression and affected health-related quality of life (HRQoL). The aims of this study were to assess HRQoL, anxiety, and depression pre- and post-diagnosis in patients undergoing...

MPEG2 video parameter and no reference PSNR estimation

DEFF Research Database (Denmark)

Li, Huiying; Forchhammer, Søren

2009-01-01

MPEG coded video may be processed for quality assessment or postprocessed to reduce coding artifacts or transcoded. Utilizing information about the MPEG stream may be useful for these tasks. This paper deals with estimating MPEG parameter information from the decoded video stream without access t...

Study about diagnostic quality in a public-center of mammography of Santa Fe, Argentina

International Nuclear Information System (INIS)

Lescano, R.; Kiguen, J.; Gaitan, L.; Caspani, C.

2001-01-01

The objective is to apply a method that allows us to evaluate the diagnostic quality of a public-center of mammography and to validate it. The representative centers of a social class were grouped; this one is evaluated measuring the mechanics, electrics, dosimetrics and personal parameters of the process to get the mammography diagnostic. The original study and the respective report was submitted to the valuation of a panel of experts, who evaluated image, techniques and diagnostics. The equipment and techniques used are described in this case. The judgment of the ACR and the Argentine legislation are applied. The dosimetric results of the mammography practice serve to determine the local reference levels. The people who intervened in the diagnosis are evaluated, as well as the services that can influence it. Seeking the parametric sensibility in relationship with the succeeded and precocious diagnosis, the success of it is confirmed by the panel of experts. We conclude by indicating that the success percentage in the diagnosis is about 98,36%, that there is 100% of coincidence among the perception and the value of the study quality. The valuation of the image reaches 69,2% of the maximum score, and the placement technique, 73,9%. The parametric sensibilities of the principal variables are discussed. (author)

Using technique vibration diagnostics for assessing the quality of power transmission line supports repairs

Directory of Open Access Journals (Sweden)

Cherpakov Aleksander

2017-01-01

Full Text Available The considered method for assessing the quality of the repair work to restore the rack supports of transmission lines is based on the method of vibration diagnostics. Power transmission line supports with a symmetrical destruction of the protective layer of concrete in the ground in violation of the construction section were chosen as an object. Finite element modelling package Ansys was used in assessing the quality of repair work. The example of evaluating the quality of repair using the relative adhesion defective area design criteria in the analysis of natural vibration frequencies is given.

Energy-Efficient Bandwidth Allocation for Multiuser Scalable Video Streaming over WLAN

Directory of Open Access Journals (Sweden)

Lafruit Gauthier

2008-01-01

Full Text Available Abstract We consider the problem of packet scheduling for the transmission of multiple video streams over a wireless local area network (WLAN. A cross-layer optimization framework is proposed to minimize the wireless transceiver energy consumption while meeting the user required visual quality constraints. The framework relies on the IEEE 802.11 standard and on the embedded bitstream structure of the scalable video coding scheme. It integrates an application-level video quality metric as QoS constraint (instead of a communication layer quality metric with energy consumption optimization through link layer scaling and sleeping. Both energy minimization and min-max energy optimization strategies are discussed. Simulation results demonstrate significant energy gains compared to the state-of-the-art approaches.

Introduction of spirometry into clinical practice in Georgetown, Guyana: quality and diagnostic outcomes.

Science.gov (United States)

Johnston, J C; Rempel, C; Sanders, C; Piggott, E; Maxwell, Y; Jaipersaud, K; Luknauth, R; Persaud, D; Rambaran, M; Levy, R D

2016-09-01

Georgetown Public Hospital Corporation (GPHC), a 600-bed publicly funded referral hospital in Georgetown, Guyana. To assess spirometry quality and diagnostic outcomes 2 years after the introduction of spirometry into routine clinical practice at GPHC. We performed a retrospective review of 476 consecutive spirometry assessments performed from November 2013 to November 2015. We assessed the proportion and trend of spirometry tests meeting acceptability criteria, along with diagnostic interpretations and spirometry laboratory referral patterns. Overall, 80.4% of the 454 initial spirometry measurements on unique patients met the acceptability criteria, with no significant change in the proportion of acceptable spirometry over the study period (P = 0.450). Of the 369 (81.3%) first tests considered interpretable, 139 (30.6%) were normal, 151 (33.3%) were obstructive, 54 (11.9%) were suggestive of a restrictive pattern, 25 (5.5%) were suggestive of a mixed disorder and 119 (26.2%) tests met the definition of reversibility. Over a 2-year period, high-quality spirometry was performed in GPHC, a publicly funded hospital in a middle-income country with no pre-existing specialised respiratory service.

On the relationship between perceptual impact of source and channel distortions in video sequences

DEFF Research Database (Denmark)

Korhonen, Jari; Reiter, Ulrich; You, Junyong

2010-01-01

It is known that peak signal-to-noise ratio (PSNR) can be used for assessing the relative qualities of distorted video sequences meaningfully only if the compared sequences contain similar types of distortions. In this paper, we propose a model for rough assessment of the bias in PSNR results, when...... video sequences with both channel and source distortion are compared against video sequences with source distortion only. The proposed method can be used to compare the relative perceptual quality levels of video sequences with different distortion types more reliably than using plain PSNR....

Quality of life evaluation of workers for diagnostic radiology services

International Nuclear Information System (INIS)

Fernandes, Ivani Martins

2011-01-01

The main objective of this study was to evaluate the quality of life (QOL) of diagnostic radiology services workers at a hospital of Sao Paulo city. It aimed also to draw the profile of these workers identifying the variables, as its influence on their quality of life. A descriptive exploratory study with qualitative and quantitative approaches was carried out. The data were collected using the questionnaires: the abbreviated instrument for the assessment of the QOL, World Health Organization Quality of Life Instrument bref (WHOQOL-bref) and a questionnaire including the social demographic variables, work conditions and the variables that express the lifestyle of individuals, both questionnaires self-applied. The sample was formed by 118 workers, among them: physicians, technologists/technicians in radiology, nurses, technicians and assistants in nursing, and others health professionals. The data analysis included descriptive statistics, nonparametric tests and the use of a linear regression model. The reliability of the instrument for the studied sample was verified by Cronbach's Alpha Coefficient (α). The WHOQOL-bref proved to be an adequate instrument, with a good level of internal consistency (α=0.884), being easily and quickly administrated for the evaluation of the QOL. The study provided an overview of the perception of quality of life of the studied group. (author)

Psychogenic Tremor: A Video Guide to Its Distinguishing Features

Directory of Open Access Journals (Sweden)

Joseph Jankovic

2014-08-01

Full Text Available Background: Psychogenic tremor is the most common psychogenic movement disorder. It has characteristic clinical features that can help distinguish it from other tremor disorders. There is no diagnostic gold standard and the diagnosis is based primarily on clinical history and examination. Despite proposed diagnostic criteria, the diagnosis of psychogenic tremor can be challenging. While there are numerous studies evaluating psychogenic tremor in the literature, there are no publications that provide a video/visual guide that demonstrate the clinical characteristics of psychogenic tremor. Educating clinicians about psychogenic tremor will hopefully lead to earlier diagnosis and treatment. Methods: We selected videos from the database at the Parkinson's Disease Center and Movement Disorders Clinic at Baylor College of Medicine that illustrate classic findings supporting the diagnosis of psychogenic tremor.Results: We include 10 clinical vignettes with accompanying videos that highlight characteristic clinical signs of psychogenic tremor including distractibility, variability, entrainability, suggestibility, and coherence.Discussion: Psychogenic tremor should be considered in the differential diagnosis of patients presenting with tremor, particularly if it is of abrupt onset, intermittent, variable and not congruous with organic tremor. The diagnosis of psychogenic tremor, however, should not be simply based on exclusion of organic tremor, such as essential, parkinsonian, or cerebellar tremor, but on positive criteria demonstrating characteristic features. Early recognition and management are critical for good long-term outcome.

An instrument for X-ray set quality assurance measurements