Multimedia applications have been evolving towards providing users with more immersive and realistic experiences. A common way to model the light available for the users' eyes is the so-called plenoptic function -...
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A wireless camera sensor network is useful for surveillance and monitoring for its visibility and easy deployment. However, it suffers from the limited capacity of wireless communication and a network is easily overfl...
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A wireless camera sensor network is useful for surveillance and monitoring for its visibility and easy deployment. However, it suffers from the limited capacity of wireless communication and a network is easily overflown with a considerable amount of video traffic. In this paper, we propose an autonomous video coding rate control mechanism where each camera sensor node can autonomously determine its codingrate in accordance with the location and velocity of target objects. For this purpose, we adopted a biological model, i.e., reaction-diffusion model, inspired by the similarity of biological spatial patterns and the spatial distribution of video codingrate. Through simulation and practical experiments, we verify the effectiveness of our proposal.
Due to the limitation of wireless communication capacity, a camera sensor network will be easily congested and the perceived video quality considerably deteriorates, when all nodes generate and transmit high-quality v...
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ISBN:
(纸本)9781424426645
Due to the limitation of wireless communication capacity, a camera sensor network will be easily congested and the perceived video quality considerably deteriorates, when all nodes generate and transmit high-quality video data. To tackle this problem, taking into account that not all video data are equally important from a viewpoint of surveillance or observation applications, our research group proposes an autonomous control mechanism, where each node appropriately determines its video codingrate according to the location and velocity of targets without any centralized control. In this paper, we implemented the mechanism and conducted practical experiments. We verified that the video codingrate was appropriately adjusted and the loss of packets was suppressed. Consequently, the perceived video quality was higher than the cases where the lowest codingrate was always used to avoid congestion and the highest codingrate was always used intending the high quality video.
At low bit rate, most computation in Tier-1 of JPEG2000 is redundant. A novel Slope Threshold Descending with Minimal Slope Discarding (STDMSD) ratecontrol method is proposed to alleviate this problem. In this algori...
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At low bit rate, most computation in Tier-1 of JPEG2000 is redundant. A novel Slope Threshold Descending with Minimal Slope Discarding (STDMSD) ratecontrol method is proposed to alleviate this problem. In this algorithm, by initially setting a larger threshold of rate-distortion slope and marking the channels that their rate-distortion slopes are larger than the thresholds in each coding block as selected state, and then decreasing the threshold step by step until the sum of the rate of those selection exceeds the predefined rate limitation, an approximate optimal truncation point will be obtained. Then, the minimal slope discarding method is applied to obtain the optimal truncation point and the ratecontrol is realized. The proposed method can effectively reduce the computation of Tier-1 up to 84.5% and cause only 0.094 dB PSNR loss for the reconstructed image in the case of 0.25 bpp bit rate.
As a coding algorithm in which picture processing can be applied directly to the compressed data, the author has proposed a surface-fitting method (B-spline coding) for the variation of the pixel values using the B-sp...
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As a coding algorithm in which picture processing can be applied directly to the compressed data, the author has proposed a surface-fitting method (B-spline coding) for the variation of the pixel values using the B-sp...
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As a coding algorithm in which picture processing can be applied directly to the compressed data, the author has proposed a surface-fitting method (B-spline coding) for the variation of the pixel values using the B-spine surfaces. It was shown that the performance of the new algorithm is equal to or better than the one in the DCT system, even for the compression efficiency. On the other hand, in some compression coding systems dealing with picture data, it is required that the coding is completed for one picture at a predetermined rate. Such problems of controlling the codingrate have not been studied for B-spline coding. In this paper, a method is proposed for dealing with the above problems. In addition, an effort is made to enhance the performance of B-spline surfaces as a compression tool. In this paper, the number of coded bits of each block is controlled by adaptive feedback, depending on the fineness of the picture pattern and the actual number of coded bits generated. A performance evaluation shows that the deviation of the actual number of coded bits from the specified number can be kept within 1%, while the compression performance (better than that of the DCT system) is maintained, and that coding rate control is possible in B-spline coding. (C) 1997 Scripta Technica, Inc.
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