Author
Alan C. Bovik
Other affiliations: University of Illinois at Urbana–Champaign, University of Sydney, Intel ...read more
Bio: Alan C. Bovik is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Image quality & Video quality. The author has an hindex of 102, co-authored 837 publications receiving 96088 citations. Previous affiliations of Alan C. Bovik include University of Illinois at Urbana–Champaign & University of Sydney.
Papers published on a yearly basis
Papers
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26 May 2013TL;DR: It is shown that the proposed model can effectively predict the TVSQ of rate-adaptive videos in an online manner, which is necessary to be able to conduct QoE-optimized online rate- Adaptation for HTTP-based video streaming.
Abstract: Newly developed HTTP-based video streaming technology enables flexible rate-adaptation in varying channel conditions. The users' Quality of Experience (QoE) of rate-adaptive HTTP video streams, however, is not well understood. Therefore, designing QoE-optimized rate-adaptive video streaming algorithms remains a challenging task. An important aspect of understanding and modeling QoE is to be able to predict the up-to-the-moment subjective quality of video as it is played. We propose a dynamic system model to predict the time-varying subjective quality (TVSQ) of rate-adaptive videos that is transported over HTTP. For this purpose, we built a video database and measured TVSQ via a subjective study. A dynamic system model is developed using the database and the measured human data. We show that the proposed model can effectively predict the TVSQ of rate-adaptive videos in an online manner, which is necessary to be able to conduct QoE-optimized online rate-adaptation for HTTP-based video streaming.
28 citations
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01 Dec 2009TL;DR: In this paper, the frequency response of linear image processing filters is characterized in terms of their frequency responses, specifically by their spectrum shaping properties, and a broad class of filters have some generalized applications.
Abstract: Publisher Summary Linear image processing filters are characterized in terms of their frequency responses, specifically by their spectrum shaping properties. Coarse descriptions that apply to many two-dimension image processing filters include lowpass, bandpass, or highpass. In such cases, the frequency response is primarily a function of radial frequency, and may even be circularly symmetric, viz., a function of U2 +V2 only. In other cases, the filter may be strongly directional or oriented, with response strongly depending on the frequency angle of the input. Of course, the terms lowpass, bandpass, highpass, and oriented are only rough qualitative descriptions of a system frequency response. Each broad class of filters has some generalized applications. For example, lowpass filters strongly attenuate all but the lower radial image frequencies (as determined by some bandwidth or cutoff frequency), and so are primarily smoothing filters. They are commonly used to reduce high-frequency noise, or to eliminate all but coarse image features, or to reduce the bandwidth of an image prior to transmission through a low-bandwidth communication channel or before sub sampling the image.
28 citations
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TL;DR: The authors present necessary and sufficient conditions such that the output from the Teager-Kaiser (1989) energy operator /spl lsqb/s/spl dot/(t)=ds(t)/dt/spl r sqb/ /spl Psi//sub c//spl l SQB/s (t)/spl r SQb/=s/ spl dot//sup 2/(t/spl minus/s(t) s/spl uml/(t) for continuous-time
Abstract: The authors present necessary and sufficient conditions such that the output from the Teager-Kaiser (1989) energy operator /spl lsqb/s/spl dot/(t)=ds(t)/dt/spl rsqb/ /spl Psi//sub c//spl lsqb/s(t)/spl rsqb/=s/spl dot//sup 2/(t)/spl minus/s(t)s/spl uml/(t) for continuous-time signals s(t) and the output from the corresponding discrete-time energy operator /spl Psi//sub d//spl lsqb/s(n)/spl rsqb/=s/sup 2/(n)/spl minus/s(n+1)s(n/spl minus/1) be non-negative everywhere. These operators have been shown to be effective for AM and FM demodulation in several useful classes of signals, such as speech and image signals. >
28 citations
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TL;DR: Two scheduling algorithms that seek to optimize the quality of scalably coded videos that have been stored at a video server before transmission are proposed and Simulation results show that the performance of both scheduling algorithms is close to a performance upper bound.
Abstract: We propose two scheduling algorithms that seek to optimize the quality of scalably coded videos that have been stored at a video server before transmission. The first scheduling algorithm is derived from a Markov decision process (MDP) formulation developed here. We model the dynamics of the channel as a Markov chain and reduce the problem of dynamic video scheduling to a tractable Markov decision problem over a finite-state space. Based on the MDP formulation, a near-optimal scheduling policy is computed that minimizes the mean square error. Using insights taken from the development of the optimal MDP-based scheduling policy, the second proposed scheduling algorithm is an online scheduling method that only requires easily measurable knowledge of the channel dynamics, and is thus viable in practice. Simulation results show that the performance of both scheduling algorithms is close to a performance upper bound also derived in this paper.
27 citations
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04 Oct 1998
TL;DR: This work designs the entire class of antisymmetric biorthogonal coiflet systems, whose filterbanks have even lengths and are linear phase, and shows that one of the novel filterbanks achieves noticeably better rate-distortion performance than several state-of-the-art filterbanks in image coding.
Abstract: Wavelet techniques have achieved a tremendous success in image data compression. In designing wavelet coding algorithms, the choice of wavelet systems is of great importance for compression performance. We design the entire class of antisymmetric biorthogonal coiflet systems, whose filterbanks have even lengths and are linear phase. We show that one of the novel filterbanks achieves noticeably better rate-distortion performance than several state-of-the-art filterbanks in image coding.
27 citations
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TL;DR: In this article, a structural similarity index is proposed for image quality assessment based on the degradation of structural information, which can be applied to both subjective ratings and objective methods on a database of images compressed with JPEG and JPEG2000.
Abstract: Objective methods for assessing perceptual image quality traditionally attempted to quantify the visibility of errors (differences) between a distorted image and a reference image using a variety of known properties of the human visual system. Under the assumption that human visual perception is highly adapted for extracting structural information from a scene, we introduce an alternative complementary framework for quality assessment based on the degradation of structural information. As a specific example of this concept, we develop a structural similarity index and demonstrate its promise through a set of intuitive examples, as well as comparison to both subjective ratings and state-of-the-art objective methods on a database of images compressed with JPEG and JPEG2000. A MATLAB implementation of the proposed algorithm is available online at http://www.cns.nyu.edu//spl sim/lcv/ssim/.
40,609 citations
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01 Jan 1998
TL;DR: An introduction to a Transient World and an Approximation Tour of Wavelet Packet and Local Cosine Bases.
Abstract: Introduction to a Transient World. Fourier Kingdom. Discrete Revolution. Time Meets Frequency. Frames. Wavelet Zoom. Wavelet Bases. Wavelet Packet and Local Cosine Bases. An Approximation Tour. Estimations are Approximations. Transform Coding. Appendix A: Mathematical Complements. Appendix B: Software Toolboxes.
17,693 citations
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21 Jul 2017TL;DR: Conditional adversarial networks are investigated as a general-purpose solution to image-to-image translation problems and it is demonstrated that this approach is effective at synthesizing photos from label maps, reconstructing objects from edge maps, and colorizing images, among other tasks.
Abstract: We investigate conditional adversarial networks as a general-purpose solution to image-to-image translation problems. These networks not only learn the mapping from input image to output image, but also learn a loss function to train this mapping. This makes it possible to apply the same generic approach to problems that traditionally would require very different loss formulations. We demonstrate that this approach is effective at synthesizing photos from label maps, reconstructing objects from edge maps, and colorizing images, among other tasks. Moreover, since the release of the pix2pix software associated with this paper, hundreds of twitter users have posted their own artistic experiments using our system. As a community, we no longer hand-engineer our mapping functions, and this work suggests we can achieve reasonable results without handengineering our loss functions either.
11,958 citations
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TL;DR: Conditional Adversarial Network (CA) as discussed by the authors is a general-purpose solution to image-to-image translation problems, which can be used to synthesize photos from label maps, reconstructing objects from edge maps, and colorizing images, among other tasks.
Abstract: We investigate conditional adversarial networks as a general-purpose solution to image-to-image translation problems. These networks not only learn the mapping from input image to output image, but also learn a loss function to train this mapping. This makes it possible to apply the same generic approach to problems that traditionally would require very different loss formulations. We demonstrate that this approach is effective at synthesizing photos from label maps, reconstructing objects from edge maps, and colorizing images, among other tasks. Indeed, since the release of the pix2pix software associated with this paper, a large number of internet users (many of them artists) have posted their own experiments with our system, further demonstrating its wide applicability and ease of adoption without the need for parameter tweaking. As a community, we no longer hand-engineer our mapping functions, and this work suggests we can achieve reasonable results without hand-engineering our loss functions either.
11,127 citations
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TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These
9,929 citations