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Estimating the number of vehicles present in traffic video sequences is a common task in applications such as active traffic management and automated route planning. There exist several vehicle counting methods such as Particle Filtering or Headlight Detection, among others. Although Principal Component Pursuit (PCP) is considered to be the state-of-the-art for video background modeling, it has not...
Sensitivity to spatial details drops across the visual periphery, and hence video streaming systems that gracefully degrades quality away from the viewpoint of the observer, provides an optimum viewing experience with potentially large bitrate savings. As reaction latency is an important performance parameter of such systems, good prediction of future gaze locations at the transmission end is very...
Content-aware image retargeting adjusts images to arbitrary sizes and preserves visually salient content. Previous algorithms formulate the problem in terms of either pixel level or mesh level structures, deforming salient objects inconsistently. To improve retargeting quality and reduce complexity, we introduced a patch-wise method to generate sparse image grids based on visual saliency and gradient...
In this paper we propose a new quality metric to estimate the impact of packet loss on the perceptual quality of encoded video sequences transmitted over error-prone networks. The proposed metric, henceforth referred to as Cumulative Distortion using Structural Similarity (CDSSIM), quantifies the overall structural distortion resulting from bidirectional error propagation in predictively coded, motion...
This paper proposes a novel approach for real-time video summarization on mobile using Dictionary Learning, Global Camera Motion analysis and Colorfulness. A dictionary is represented as a distinct set of events that are described as spatio-temporal features. Uniqueness measure is predicted based on the correlation scores of the dictionary elements whereas the quality measure is estimated using Global...
A cloud-based encoding pipeline which generates streams for video-on-demand distribution typically processes a wide diversity of content that exhibit varying signal characteristics. To produce the best quality video streams, the system needs to adapt the encoding to each piece of content, in an automated and scalable way. In this paper, we describe two algorithm optimizations for a distributed cloud-based...
Subjective studies showed that most HDR video tone mapping operators either produce disturbing temporal artifacts, or are limited in their local contrast reproduction capability. Recently, both these issues have been addressed by a novel temporally coherent local HDR tone mapping method, which has been shown, both qualitatively and through a subjective study, to be advantageous compared to previous...
The visibility of motion artifacts in a video sequence e.g. motion blur and temporal aliasing, affects perceived motion quality. The frame rate required to render these motion artifacts imperceptible is far higher than is currently feasible or specified in current video formats. This paper investigates the perception of temporal aliasing and its associated artifacts below this frame rate, along with...
In this paper, we pose a new problem of video enhancement transcoding, which converts the compressed dark video into compressed normal-lighting one. Distinct statistics of dark and normal videos result in quite different coding modes, which thus enforces latent constraints on mode conversion during transcoding. Following this idea, we propose a fast mode decision algorithm to speed up computation...
Thanks to the low operational cost and large storage capacity of smartphones and wearable devices, people are recording many hours of daily activities, sport actions and home videos. These videos, also known as egocentric videos, are generally long-running streams with unedited content, which make them boring and visually unpalatable, bringing up the challenge to make egocentric videos more appealing...
Network streaming video services have been growing explosively in the past decade, but how to measure and assure the video quality-of-experience (QoE) of end consumers is still an open problem. Poor presentation quality and playback stalling have been identified as the most dominant factors that degrade user QoE. Although both factors have been studied individually, little is known about the interactions...
Many applications benefit from sampling algorithms where a small number of well chosen samples are used to generalize different properties of a large dataset. In this paper, we use diverse sampling for streaming video summarization. Several emerging applications support streaming video, but existing summarization algorithms need access to the entire video which requires a lot of memory and computational...
Internet service providers (ISP) are deploying software defined networking (SDN), which enables them to better utilize their resources and increase their revenues by offering on-demand differentiated services. In particular, SDN makes provisioning of dynamically managed video services with multiple levels of service viable, since the controller has complete vision of network resources and can change...
Digital content consumption is exploding thanks to the advances of the distributed cloud-computing infrastructures and the consumer electronics. Further challenges have been posed to engineers and researchers to satisfy the ever increasing user needs not only for high quality video delivery, but also for richer experience. In order to support various video analysis tasks in addition to transcoding,...
Real-time video applications, such as multi party video conferencing, involve the simultaneous transport of multiple and potentially multi-layered video sources to participating or interested parties. It is desirable to mix these multiple source videos into a single video stream at intermediary nodes in the network, e.g. at Multipoint Control Units (MCU). This has the advantage of reduced application...
Mobile display has been considered as the major contributor to the energy consumption of the ever-increasing mobile video services. Current practices in display energy reduction (DER) utilize local computing resources to analyze the video content before DER strategies can be applied in a per-device fashion. For a given video, same analytical computations are repeated in millions of individual devices...
While a number of existing high-bit depth video compression methods can potentially encode high dynamic range (HDR) video, few of them provide this capability. In this paper, we investigate techniques for adapting HDR video for this purpose. In a large-scale test on 33 HDR video sequences, we compare 2 video codecs, 4 luminance encoding techniques (transfer functions) and 3 color encoding methods,...
A light field (LF) is a 2D array of closely spaced viewpoint images of a static 3D scene. In an interactive LF streaming (ILFS) scenario, a user successively requests desired neighboring viewpoints for observation, and in response the server must transmit pre-encoded data for correct decoding of the requested viewpoint images. Designing frame structures for ILFS is challenging, since at encoding time...
With the aid of tone-mapping operators, high dynamic range images can be mapped for reproduction on standard displays. However, for large restrictions in terms of display dynamic range and peak luminance, limitations of the human visual system have significant impact on the visual appearance. In this paper, we use components from the real-time noise-aware tone-mapping to complement an existing method...
Ultra low delay video transmission is becoming increasingly important. Video-based applications with ultra low delay requirements range from teleoperation scenarios such as controlling drones or telesurgery to autonomous control of dynamic processes using computer vision algorithms applied on real-time video. To evaluate the performance of the video transmission chain in such systems, it is important...
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