777 research outputs found
A no-reference optical flow-based quality evaluator for stereoscopic videos in curvelet domain
Most of the existing 3D video quality assessment (3D-VQA/SVQA) methods only consider spatial information by directly using an image quality evaluation method. In addition, a few take the motion information of adjacent frames into consideration. In practice, one may assume that a single data-view is unlikely to be sufficient for effectively learning the video quality. Therefore, integration of multi-view information is both valuable and necessary. In this paper, we propose an effective multi-view feature learning metric for blind stereoscopic video quality assessment (BSVQA), which jointly focuses on spatial information, temporal information and inter-frame spatio-temporal information. In our study, a set of local binary patterns (LBP) statistical features extracted from a computed frame curvelet representation are used as spatial and spatio-temporal description, and the local flow statistical features based on the estimation of optical flow are used to describe the temporal distortion. Subsequently, a support vector regression (SVR) is utilized to map the feature vectors of each single view to subjective quality scores. Finally, the scores of multiple views are pooled into the final score according to their contribution rate. Experimental results demonstrate that the proposed metric significantly outperforms the existing metrics and can achieve higher consistency with subjective quality assessment
Quality Assessment of Stereoscopic 360-degree Images from Multi-viewports
Objective quality assessment of stereoscopic panoramic images becomes a
challenging problem owing to the rapid growth of 360-degree contents. Different
from traditional 2D image quality assessment (IQA), more complex aspects are
involved in 3D omnidirectional IQA, especially unlimited field of view (FoV)
and extra depth perception, which brings difficulty to evaluate the quality of
experience (QoE) of 3D omnidirectional images. In this paper, we propose a
multi-viewport based fullreference stereo 360 IQA model. Due to the freely
changeable viewports when browsing in the head-mounted display (HMD), our
proposed approach processes the image inside FoV rather than the projected one
such as equirectangular projection (ERP). In addition, since overall QoE
depends on both image quality and depth perception, we utilize the features
estimated by the difference map between left and right views which can reflect
disparity. The depth perception features along with binocular image qualities
are employed to further predict the overall QoE of 3D 360 images. The
experimental results on our public Stereoscopic OmnidirectionaL Image quality
assessment Database (SOLID) show that the proposed method achieves a
significant improvement over some well-known IQA metrics and can accurately
reflect the overall QoE of perceived images
Deep Local and Global Spatiotemporal Feature Aggregation for Blind Video Quality Assessment
In recent years, deep learning has achieved promising success for multimedia
quality assessment, especially for image quality assessment (IQA). However,
since there exist more complex temporal characteristics in videos, very little
work has been done on video quality assessment (VQA) by exploiting powerful
deep convolutional neural networks (DCNNs). In this paper, we propose an
efficient VQA method named Deep SpatioTemporal video Quality assessor (DeepSTQ)
to predict the perceptual quality of various distorted videos in a no-reference
manner. In the proposed DeepSTQ, we first extract local and global
spatiotemporal features by pre-trained deep learning models without fine-tuning
or training from scratch. The composited features consider distorted video
frames as well as frame difference maps from both global and local views. Then,
the feature aggregation is conducted by the regression model to predict the
perceptual video quality. Finally, experimental results demonstrate that our
proposed DeepSTQ outperforms state-of-the-art quality assessment algorithms
End-to-end deep multi-score model for No-reference stereoscopic image quality assessment
Deep learning-based quality metrics have recently given significant
improvement in Image Quality Assessment (IQA). In the field of stereoscopic
vision, information is evenly distributed with slight disparity to the left and
right eyes. However, due to asymmetric distortion, the objective quality
ratings for the left and right images would differ, necessitating the learning
of unique quality indicators for each view. Unlike existing stereoscopic IQA
measures which focus mainly on estimating a global human score, we suggest
incorporating left, right, and stereoscopic objective scores to extract the
corresponding properties of each view, and so forth estimating stereoscopic
image quality without reference. Therefore, we use a deep multi-score
Convolutional Neural Network (CNN). Our model has been trained to perform four
tasks: First, predict the left view's quality. Second, predict the quality of
the left view. Third and fourth, predict the quality of the stereo view and
global quality, respectively, with the global score serving as the ultimate
quality. Experiments are conducted on Waterloo IVC 3D Phase 1 and Phase 2
databases. The results obtained show the superiority of our method when
comparing with those of the state-of-the-art. The implementation code can be
found at: https://github.com/o-messai/multi-score-SIQ
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