1,662 research outputs found

    Low-Complexity 3D-DWT video encoder applicable to IPTV

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    3D-DWT encoders are good candidates for applications like professional video editing, IPTV video surveillance, live event IPTV broadcast, multispectral satellite imaging, HQ video delivery, etc., where a frame must be reconstructed as fast as possible. However, the main drawback of the algorithms that compute the 3D-DWT is the huge memory requirement in practical implementations. In this paper, and in order to considerably reduce the memory requirements of this kind of video encoders, we present a new 3D-DWT video encoder based on (a) the use of a novel frame-based 3D-DWT transform that avoids video sequence partitioning in Groups Of Pictures (GOP) and (b) a very fast run-length encoder. Furthermore, an exhaustive evaluation of the proposed encoder (3D-RLW) has been performed, analyzing the sensibility of the ¿lters employed in the 3D-DWT transform and comparing the evaluation results with other video encoders in terms of R/D, coding/decoding delay and memory consumptionThanks to Spanish Ministry of Education and Science under grants DPI2007-66796-C03-03 for funding.López ., O.; Piñol ., P.; Martinez Rach, MO.; Perez Malumbres, MJ.; Oliver Gil, JS. (2011). Low-Complexity 3D-DWT video encoder applicable to IPTV. Signal Processing: Image Communication. 26(7):358-369. https://doi.org/10.1016/j.image.2011.01.008S35836926

    Similarities between explicit and implicit motor imagery in mental rotation of hands: an EEG study

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    Chronometric and imaging studies have shown that motor imagery is used implicitly during mental rotation tasks in which subjects for example judge the laterality of human hand pictures at various orientations. Since explicit motor imagery is known to activate the sensorimotor areas of the cortex, mental rotation is expected to do similar if it involves a form of motor imagery. So far, functional magnetic resonance imaging and positron emission tomography have been used to study mental rotation and less attention has been paid to electroencephalogram (EEG) which offers a high time-frequency resolution. The time-frequency analysis is an established method for studying explicit motor imagery. Although hand mental rotation is claimed to involve motor imagery, the time-frequency characteristics of mental rotation have never been compared with those of explicit motor imagery. In this study, time-frequency responses of EEG recorded during explicit motor imagery and during a mental rotation task, inducing implicit motor imagery, were compared. Fifteen right-handed healthy volunteers performed motor imagery of hands in one condition and hand laterality judgement tasks in another while EEG of the whole head was recorded. The hand laterality judgement was the mental rotation task used to induce implicit motor imagery. The time-frequency analysis and sLORETA localisation of the EEG showed that the activities in the sensorimotor areas had similar spatial and time-frequency characteristics in explicit motor imagery and implicit motor imagery conditions. Furthermore this sensorimotor activity was different for the left and for the right hand in both explicit and implicit motor imagery. This result supports that motor imagery is used during mental rotation and that it can be detected and studied with EEG technology. This result should encourage the use of mental rotation of body parts in rehabilitation programmes in a similar manner as motor imagery

    Brain function assessment in different conscious states

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    Background: The study of brain functioning is a major challenge in neuroscience fields as human brain has a dynamic and ever changing information processing. Case is worsened with conditions where brain undergoes major changes in so-called different conscious states. Even though the exact definition of consciousness is a hard one, there are certain conditions where the descriptions have reached a consensus. The sleep and the anesthesia are different conditions which are separable from each other and also from wakefulness. The aim of our group has been to tackle the issue of brain functioning with setting up similar research conditions for these three conscious states.Methods: In order to achieve this goal we have designed an auditory stimulation battery with changing conditions to be recorded during a 40 channel EEG polygraph (Nuamps) session. The stimuli (modified mismatch, auditory evoked etc.) have been administered both in the operation room and the sleep lab via Embedded Interactive Stimulus Unit which was developed in our lab. The overall study has provided some results for three domains of consciousness. In order to be able to monitor the changes we have incorporated Bispectral Index Monitoring to both sleep and anesthesia conditions.Results: The first stage results have provided a basic understanding in these altered states such that auditory stimuli have been successfully processed in both light and deep sleep stages. The anesthesia provides a sudden change in brain responsiveness; therefore a dosage dependent anesthetic administration has proved to be useful. The auditory processing was exemplified targeting N1 wave, with a thorough analysis from spectrogram to sLORETA. The frequency components were observed to be shifting throughout the stages. The propofol administration and the deeper sleep stages both resulted in the decreasing of N1 component. The sLORETA revealed similar activity at BA7 in sleep (BIS 70) and target propofol concentration of 1.2 μg/mL.Conclusions: The current study utilized similar stimulation and recording system and incorporated BIS dependent values to validate a common approach to sleep and anesthesia. Accordingly the brain has a complex behavior pattern, dynamically changing its responsiveness in accordance with stimulations and states. © 2010 Ozgoren et al; licensee BioMed Central Ltd

    Inferring human intentions from the brain data

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    Hardware Synthesis of Chip Enhancement Trasformations in Hardware Description Language Environment

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    Human analyze different sight in daily life images to perceive their environment. More than 99% of the activity of human brain is involved in processing images from the visual cortex. A visual image is rich in information and can save thousand words. Many real world images are acquired with low contrast and unsuitable for human eyes to read, such as industrial and medical X-ray images. Image enhancement is a classical problem in image processing and computer vision. The image enhancement is widely used for image processing and as a preprocessing step in texture synthesis, speech recognition, and many other image/video processing applications. The main challenge is to transpose the validated algorithms into a language as hardware description languages. It is also the need that the input and output data files should be reshaped to match the binary content permitted into the hardware simulators. Research focuses on Simulation, Design and Synthesis of 2D and 3D Image enhancement chip in Hardware description language (HDL) Environment. The chip implementation of image enhancement algorithm is done using Discrete Wavelet Transformation (DWT) and Inverse Modified Discrete Cosine Transformation (IMDCT). Hardware chip modeling and simulation is done in Xilinx 14.2 ISE Simulator. Synthesis environment is carried out on Diligent Sparten-3E FPGA. . Image enhanced values are seen in the waveform editor of Modelsim software

    Analysis and Performance Optimization of a GPGPU Implementation of Image Quality Assessment (IQA) Algorithm VSNR

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    abstract: Image processing has changed the way we store, view and share images. One important component of sharing images over the networks is image compression. Lossy image compression techniques compromise the quality of images to reduce their size. To ensure that the distortion of images due to image compression is not highly detectable by humans, the perceived quality of an image needs to be maintained over a certain threshold. Determining this threshold is best done using human subjects, but that is impractical in real-world scenarios. As a solution to this issue, image quality assessment (IQA) algorithms are used to automatically compute a fidelity score of an image. However, poor performance of IQA algorithms has been observed due to complex statistical computations involved. General Purpose Graphics Processing Unit (GPGPU) programming is one of the solutions proposed to optimize the performance of these algorithms. This thesis presents a Compute Unified Device Architecture (CUDA) based optimized implementation of full reference IQA algorithm, Visual Signal to Noise Ratio (VSNR) that uses M-level 2D Discrete Wavelet Transform (DWT) with 9/7 biorthogonal filters among other statistical computations. The presented implementation is tested upon four different image quality databases containing images with multiple distortions and sizes ranging from 512 x 512 to 1600 x 1280. The CUDA implementation of VSNR shows a speedup of over 32x for 1600 x 1280 images. It is observed that the speedup scales with the increase in size of images. The results showed that the implementation is fast enough to use VSNR on high definition videos with a frame rate of 60 fps. This work presents the optimizations made due to the use of GPU’s constant memory and reuse of allocated memory on the GPU. Also, it shows the performance improvement using profiler driven GPGPU development in CUDA. The presented implementation can be deployed in production combined with existing applications.Dissertation/ThesisMasters Thesis Computer Science 201

    Real-time human ambulation, activity, and physiological monitoring:taxonomy of issues, techniques, applications, challenges and limitations

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    Automated methods of real-time, unobtrusive, human ambulation, activity, and wellness monitoring and data analysis using various algorithmic techniques have been subjects of intense research. The general aim is to devise effective means of addressing the demands of assisted living, rehabilitation, and clinical observation and assessment through sensor-based monitoring. The research studies have resulted in a large amount of literature. This paper presents a holistic articulation of the research studies and offers comprehensive insights along four main axes: distribution of existing studies; monitoring device framework and sensor types; data collection, processing and analysis; and applications, limitations and challenges. The aim is to present a systematic and most complete study of literature in the area in order to identify research gaps and prioritize future research directions
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