997 research outputs found

    Providing 3D video services: the challenge from 2D to 3DTV quality of experience

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    Recently, three-dimensional (3D) video has decisively burst onto the entertainment industry scene, and has arrived in households even before the standardization process has been completed. 3D television (3DTV) adoption and deployment can be seen as a major leap in television history, similar to previous transitions from black and white (B&W) to color, from analog to digital television (TV), and from standard definition to high definition. In this paper, we analyze current 3D video technology trends in order to define a taxonomy of the availability and possible introduction of 3D-based services. We also propose an audiovisual network services architecture which provides a smooth transition from two-dimensional (2D) to 3DTV in an Internet Protocol (IP)-based scenario. Based on subjective assessment tests, we also analyze those factors which will influence the quality of experience in those 3D video services, focusing on effects of both coding and transmission errors. In addition, examples of the application of the architecture and results of assessment tests are provided

    NASA Automated Rendezvous and Capture Review. Executive summary

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    In support of the Cargo Transfer Vehicle (CTV) Definition Studies in FY-92, the Advanced Program Development division of the Office of Space Flight at NASA Headquarters conducted an evaluation and review of the United States capabilities and state-of-the-art in Automated Rendezvous and Capture (AR&C). This review was held in Williamsburg, Virginia on 19-21 Nov. 1991 and included over 120 attendees from U.S. government organizations, industries, and universities. One hundred abstracts were submitted to the organizing committee for consideration. Forty-two were selected for presentation. The review was structured to include five technical sessions. Forty-two papers addressed topics in the five categories below: (1) hardware systems and components; (2) software systems; (3) integrated systems; (4) operations; and (5) supporting infrastructure

    Performance Comparison for Ballistocardiogram Peak Detection Methods

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    Citation: Suliman, A., Carlson, C., Ade, C. J., Warren, S., & Thompson, D. E. (2019). Performance Comparison for Ballistocardiogram Peak Detection Methods. IEEE Access, 7, 53945–53955. https://doi.org/10.1109/ACCESS.2019.2912650A number of research groups have proposed methods for ballistocardiogram (BCG) peak detection toward the identification of individual cardiac cycles. However, objective comparisons of these proposed methods are lacking. This paper, therefore, conducts a systematic and objective performance evaluation and comparison of several of these approaches. Five peak-detection methods (three replicated from the literature and two adapted from code provided by the methods' authors) are compared using data from 30 volunteers. A basic cross-correlation approach was also included as a sixth method. Two high-performing methods were identified: the method proposed by Sadek et al. and the method proposed by Brüser et al. The first achieved the highest average peak-detection rate of 94%, the lowest average false alarm rate of 0.0552 false alarms per second, and a relatively small mean absolute error between the real and detected peaks: 0.0175 seconds. The second method achieved the lowest mean absolute error of 0.0088 seconds between the real and detected peaks, an average peak-detection success rate of 89%, and 0.0766 false alarms per second. All metrics are averaged across participants

    A Computational Model Of The Intelligibility Of American Sign Language Video And Video Coding Applications

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    Real-time, two-way transmission of American Sign Language (ASL) video over cellular networks provides natural communication among members of the Deaf community. Bandwidth restrictions on cellular networks and limited computational power on cellular devices necessitate the use of advanced video coding techniques designed explicitly for ASL video. As a communication tool, compressed ASL video must be evaluated according to the intelligibility of the conversation, not according to conventional definitions of video quality. The intelligibility evaluation can either be performed using human subjects participating in perceptual experiments or using computational models suitable for ASL video. This dissertation addresses each of these issues in turn, presenting a computational model of the intelligibility of ASL video, which is demonstrated to be accurate with respect to true intelligibility ratings as provided by human subjects. The computational model affords the development of video compression techniques that are optimized for ASL video. Guided by linguistic principles and human perception of ASL, this dissertation presents a full-reference computational model of intelligibility for ASL (CIM-ASL) that is suitable for evaluating compressed ASL video. The CIM-ASL measures distortions only in regions relevant for ASL communication, using spatial and temporal pooling mechanisms that vary the contribution of distortions according to their relative impact on the intelligibility of the compressed video. The model is trained and evaluated using ground truth experimental data, collected in three separate perceptual studies. The CIM-ASL provides accurate estimates of subjective intelligibility and demonstrates statistically significant improvements over computational models traditionally used to estimate video quality. The CIM-ASL is incorporated into an H.264/AVC compliant video coding framework, creating a closed-loop encoding system optimized explicitly for ASL intelligibility. This intelligibility optimized coder achieves bitrate reductions between 10% and 42% without reducing intelligibility, when compared to a general purpose H.264/AVC encoder. The intelligibility optimized encoder is refined by introducing reduced complexity encoding modes, which yield a 16% improvement in encoding speed. The purpose of the intelligibility optimized encoder is to generate video that is suitable for real-time ASL communication. Ultimately, the preferences of ASL users determine the success of the intelligibility optimized coder. User preferences are explicitly evaluated in a perceptual experiment in which ASL users select between the intelligibility optimized coder and a general purpose video coder. The results of this experiment demonstrate that the preferences vary depending on the demographics of the participants and that a significant proportion of users prefer the intelligibility optimized coder

    Divide and Conquer in Neural Style Transfer for Video

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    Neural Style Transfer is a class of neural algorithms designed to redraw a given image in the style of another image, traditionally a famous painting, while preserving the underlying details. Applying this process to a video requires stylizing each of its component frames, and the stylized frames must have temporal consistency between them to prevent flickering and other undesirable features. Current algorithms accommodate these constraints at the expense of speed. We propose an algorithm called Distributed Artistic Videos and demonstrate its capacity to produce stylized videos over ten times faster than the current state-of-the-art with no reduction in output quality. Through the use of an 8-node computing cluster, we reduce the average time required to stylize a video by 92%—from hours to minutes---compared to the most recent algorithm of this kind on the same equipment and input. This allows the stylization of videos that are longer and higher-resolution than previously feasible

    NASA/ASEE Summer Faculty Fellowship Program, 1990, Volume 1

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    The 1990 Johnson Space Center (JSC) NASA/American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program was conducted by the University of Houston-University Park and JSC. A compilation of the final reports on the research projects are presented. The topics covered include: the Space Station; the Space Shuttle; exobiology; cell biology; culture techniques; control systems design; laser induced fluorescence; spacecraft reliability analysis; reduced gravity; biotechnology; microgravity applications; regenerative life support systems; imaging techniques; cardiovascular system; physiological effects; extravehicular mobility units; mathematical models; bioreactors; computerized simulation; microgravity simulation; and dynamic structural analysis

    Doctor of Philosophy in Rehabilitation Science

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    dissertationMultiple Sclerosis (MS) is a chronic, neurological disorder characterized by imbalance and falls. Accurate perception and integration of three sensory inputs - the vestibular, vision, and somatosensory, is critical to produce human gaze and posture orientation. In MS, demyelination of pathways within the brainstem and cerebellum adversely affect gaze and postural stability. However, the deficits and the psychometric properties of these measures remain less examined. Moreover, the benefits of training on gaze and postural stability are unknown in MS. This study examined the deficits in gaze stability, dynamic balance, and self-report measures in persons with MS as compared to controls; assessed the test-retest reliability and response stability of gaze stability, postural sway, and dynamic balance tests; and investigated the effects of training on gaze stability, galvanic-induced postural sway, dynamic balance, and self-report measures in persons with MS. We hypothesized that persons with MS will demonstrate deficits in gaze and postural stability; that study measures will demonstrate moderate to good reliability and acceptable response stability; and that persons with MS will demonstrate significant improvements after training. Nineteen persons with MS at fall-risk and 14 controls were recruited and the assessments were carried out on 2 occasions. The participants then completed a 2-week training followed by re-assessments. Persons with MS demonstrated significant differences in the gaze stability, dynamic balance, and self-report measures versus controls. In addition, significant inter-relationships were found. The majority of gaze stabilization measures demonstrated moderate while the postural sway and dynamic balance measures showed good reliability. The aVOR gain, FGA, and FSST showed SEM % <20 and MDD95% <20, suggesting acceptable response stability. After training, gaze stability was achieved by recruiting substitutive oculomotor strategies whereas postural stability was achieved by sway response adaptations. Consistent improvements in dynamic balance and self-report measures suggest clinically meaningful changes. Taken together, these findings support the study hypothesis and suggest that significant deficits in gaze and posture may be present in persons with MS. This highlights the utility of these assessments in fall-risk evaluations in persons with MS. Moreover, the different strategical mechanisms for improvements after training suggest the clinical value of a focused training intervention
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