1,720,968 research outputs found
Video Quality of Experience metric for streaming services
No full textThe knowledge of the user Quality of Experience (QoE) of the accessed services is of crucial importance for the robust design and adaptation of multimedia streaming networks. In this article, a video QoE estimation metric for video streaming services is presented. The proposed metric does not require information on the original video or the impairments affecting the communication channels. Results show that the proposed method can efficiently estimate the video QoE
Toward the Perceptual Quality Evaluation of Compressed Light Field Images
Full text linkEvaluation of perceived quality of light field images,as well as testing new processing tools, or even assessing the effectiveness of objective quality metrics, relies on the availabilityof test dataset and corresponding quality ratings. This article presents SMART light field image quality dataset. The dataset consists of source images (raw data without optical corrections), compressed images, and annotated subjective quality scores. Furthermore, analysis of perceptual effects of compression on SMART dataset is presented. Next, the impact of image content on the perceived quality is studied with the help of image quality attributes. Finally, the performances of 2D image quality metrics when applied to light field images are analyzed.</p
No-Reference Light Field Image Quality Assessment Exploiting Saliency
Full text linkIn the near future, the broadcasting scenario will be characterized by immersive content. One of the systems for capturing the 3D content of a scene is the Light Field imaging. The huge amount of data and the specific transmission scenario impose strong constraints on services and applications. Among others, the evaluation of the quality of the received media cannot rely on the original signal but should be based only on the received data. In this direction, we propose a no-reference quality metric for light field images which is based on spatial and angular characteristics. In more details, the estimated saliency and cyclopean maps of light field images are exploited to extract the spatial features. The angular consistency features are, instead, measured with the use of the Global Luminance Distribution knowledge and the Weighted Local Binary Patterns operator on Epipolar Plane Images. The effectiveness of the proposed metric is assessed by comparing its performance with state-of-the-art quality metrics using 4 datasets: SMART, Win5-LID, VALID 10-bit, and VALID 8-bit. Furthermore, the performance is analyzed in cross-datasets, with different distortions, and for different saliency maps. The achieved results show that the performance of the proposed model outperforms state-of-the-art approaches and perform well for different distortion types and with various saliency models
Reduced Reference Quality Assessment of Light Field Images
No full textImmersive media, such as free view point video and 360° video, are expected to be dominant as broadcasting services. The light field (LF) imaging is being considered as a next generation imaging technology offering the possibility to provide new services, including six degree-of-freedom video. The drawback of this technology is in the size of the generated content thus requiring novel compression systems and the design of ad-hoc methodologies for evaluating the perceived quality. In this paper, the relation between depth map quality and overall quality of LF image is studied. Next, a reduced reference quality assessment metric for LF images is presented. To predict the quality of distorted LF images, the measure of distortion in the depth map is exploited. To test and validate the proposed framework, a subjective experiment has been performed, and a LF image quality dataset has been created. The dataset is also used for evaluating the performance of state-of-the-art quality metrics, when applied to LF images. The achieved results evidence that the estimated quality score by the proposed framework has a significant correlation with subjective quality rating. Consequently, reference data can be delivered to the clients thus allowing the local estimation of the perceived quality of service
Impact of Video Content and Transmission Impairments on Quality of Experience
No full textThe analysis of the impact of video content and transmission impairments on Quality of Experience (QoE) is a relevant topic for the robust design and adaptation of multimedia infrastructures, services, and applications. The goal of this paper is to study the impact of video content on QoE for different levels of impairments. In more details, this contribution aims at i) the study of the impact of delay, jitter, packet loss, and bandwidth on QoE, ii) the analysis of the impact of video content on QoE, and iii) the evaluation of the relationship between content related parameters (spatial-temporal perceptual information, motion, and data rate) and the QoE for different levels of impairments
Evaluation of the Effects of Transmission Impairments on Perceived Video Quality by exploiting ReTRiEVED Dataset
No full textThe robust design and adaptation of multimedia networks relies on the study of the influence of potential network impairments on the perceived quality. Video quality may be affected by network impairments, such as delay, jitter, packet loss, and bandwidth, and the perceptual impact of these impairments may vary according to the video content. The effects of packet loss and encoding artifacts on the perceived quality have been widely addressed in the literature. However, the relationship between video content and network impairments on the perceived video quality has not been deeply investigated. A detailed analysis of ReTRiEVED test video dataset, designed by considering a set of potential network impairments, is presented, and the effects of transmission impairments on perceived quality are analyzed. Furthermore, the impact on the perceived quality of the video content in the presence of transmission impairments is studied by using video content descriptors. Finally, the performances of well-known quality metrics are tested on the proposed dataset
Effect of Visualization Techniques on Subjective Quality of Light Field Images
No full textLight Field imaging derives from the fundamentals of light field sampling, where the spatial information about a scene can be captured with angular information. That is, the Light Field imaging is based on a camera recording information about the intensity of light from the scene and about the direction of the light rays. The acquired data can be shown to the user in different ways, such as image with digitally extended depth of field, 3D, parallax, and 360 degree display. In this contribution, the impact of different rendering techniques on the Quality of Experience is addressed. The achieved results show that the visualization techniques may have different impact on the perceived quality even when the same content is considered
QoS to QoE mapping model for wired/wireless video communication
No full textMultimedia service providers have to deliver video content through bandwidth limited and error-prone networks with agreed level of perceived video quality to customers for specific applications. To this aim service providers must devise a strategy to monitor the perceived quality and automatically adapt it when necessary. Measuring perceived quality is challenging for service providers. So there is the need for a mapping model to predict perceived video quality from system related quality of service parameters. In this article performance comparison of widely used quality of service to quality of experience mapping models has been presented and optimal solution has been recommended for key quality of service parameters: jitter, delay, packet loss rate and throughput limitation. For this purpose the freely available video quality database ReTRiEVED has been used
A study of the impact of light fields watermarking on the perceived quality of the refocused data
No full textSecuring multimedia data from undesired manipulation is a widely investigated topic in the state of the art. A large number of techniques has been developed for protecting images, videos, and also audio from malicious attacks. Nowadays new imaging systems pose new challenges from the data protection point of view. In particular, plenoptic cameras allow to record multiple views of a scene by using a single camera in a single shot, thus avoiding the problems related to calibration and camera synchronization. In this contribution, a novel embedding scheme tuned to light fields is presented. The watermark is inserted in the horizontal and vertical detail subbands of the first level of the Haar wavelet transform. The aim of this work is twofold: the design of a water-marking system that does not affect the depth map estimation procedure and therefore the refocusing procedure and the 3D scene reconstruction. On the other hand, the impact of light field data modification with respect to the perceived quality has been investigated. Experimental tests, both objective and subjective, have been carried out for assessing the performances of the proposed algorithm
Study of the effects of video content on quality of experience
No full textIn this article the effects of video content on Quality of Experience (QoE) have been presented. Delivery of the video content with high level of QoE from bandwidth-limited and error-prone network is of crucial importance for the service providers. Therefore, it is of fundamental importance to analyse the impact of the network impairments and video content on perceived quality during the QoE metric design. The major contributions of the article are in the study of i)the impact of network impairments together with video content, ii) impact of the video content and ii) the impact of video content related parameters: spatial-temporal perceptual information, video content, and frame size on QoE has been presented. The results show that when the impact of impairments on perceived quality is low, the quality is significantly influenced by video content, and video content itself also has a significant impact on QoE. Finally, the results strengthen the need for new parameter characterization, for better QoE metric design
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