Compared to full encryption approaches, selective encryption approaches are known to protect JPEG images from attacks with minimum overhead for Wireless Sensor Networks (WSNs). Since data resulting from DCT transform ...
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Compared to full encryption approaches, selective encryption approaches are known to protect JPEG images from attacks with minimum overhead for Wireless Sensor Networks (WSNs). Since data resulting from DCT transform is correlated with each other, however, the unencrypted data in selective encryption approaches can give attackers some hint for guessing the encrypted data. In this paper, we propose away to apply full encryption to image transmission over WSNs by offloading the computational workload of sensors to a server. Based on the experimental results, we show that the proposed approach can ensure both the higher security level and the energy-efficiency at a sensor with acceptable image quality.
The idea of multiple description video coding has been introduced to deal with the issues of bandwidth/path diversity and packet loss due to network congestion and/or error-prone channels which might cause serious qua...
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The idea of multiple description video coding has been introduced to deal with the issues of bandwidth/path diversity and packet loss due to network congestion and/or error-prone channels which might cause serious quality degradation in video applications such as multimedia streaming and video conferencing services. In this paper, two approaches to description generation are proposed to produce multiple descriptions at higher coding efficiency. One of them is motivated by the multiple description scalar quantizer to reduce the distortion and the other is the coefficient partition in transform domain in order to balance the descriptions better. An estimation mechanism is further proposed to alleviate the drifting problem due to description fluctuation by synchronizing the reference frames at the encoder and the decoder as much as possible. The experiments show that the proposed methods offer substantial improvement at the event of description loss.
Making efficient use of video information requires the development of a video signature and a similarity measure to rapidly identify similar videos in a huge database. Most of existing techniques to address this probl...
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Making efficient use of video information requires the development of a video signature and a similarity measure to rapidly identify similar videos in a huge database. Most of existing techniques to address this problem have focused on the uncompressed domain. However, decoding and analyzing of a video sequence are extremely time-consuming tasks. Since video data are usually available in compressed form, it is desirable to directly process video material without decoding. In this paper, we present a novel approach for comparing video sequences that works in the compressed domain. The proposed method is based on recognizing motion patterns extracted from the video stream and their occurrence histogram is proven to be a powerful feature for describing the video content. Experiments on a TRECVID 2010 dataset show that our approach presents high accuracy relative to the state-of- the-art solutions and in a computational time that makes it suitable for large collections.
For image compression applications where the information sink is not a person but a computer algorithm, the image encoder should control the encoding process in such a way that the important and relevant features of t...
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For image compression applications where the information sink is not a person but a computer algorithm, the image encoder should control the encoding process in such a way that the important and relevant features of the image are preserved after compression. In this paper, our goal is to preserve the strongest SIFT features for JPEG-encoded images. We analyze the relevant characteristics of SIFT features and categorize the image Macroblocks into several groups. Then we propose a novel rate-distortion model which is based on the SIFT feature matching score. The dependency between the quantization table in the JPEG file and the common Lagrange multiplier is obtained from a training image database. Then for a given image quality we exploit this relationship to perform R-D optimization for each group. Our results show that the proposed algorithm achieves better feature preservation when compared to standard JPEG encoding. The proposed approach is fully standard compatible.
Nowadays the importance of multilink networks where end-to-end connections are provided by applying multiple communication links simultaneously is rapidly growing due to the expanding demand for high-speed Internet ac...
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Nowadays the importance of multilink networks where end-to-end connections are provided by applying multiple communication links simultaneously is rapidly growing due to the expanding demand for high-speed Internet access and real-time video transmission. Since channel conditions may vary in time and space, the selection of the used communication links depends on traffic load, latency, coverage and desired data rate. Combining multilink architecture and adaptive video transmission can be therefore an effective solution for broadcasting video streams. In this paper the efficiency of the adaptive transmission scheme will be presented for a terrestrial heterogeneous multilink network which consists of WiMAX, LTE and HSDPA communication links.
Motion detection is an important computer vision problem that has been used in different applications including surveillance. Most of the applications require fast processing due to their real time nature. The GPU (Gr...
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Motion detection is an important computer vision problem that has been used in different applications including surveillance. Most of the applications require fast processing due to their real time nature. The GPU (Graphic Processing Unit) is used as a cost-efficient tool that provides great opportunities for parallel processing. This paper studies the performance of the GPU in implementing a realistic motion detection application and compares the performance of multiple GPUs and CPU for this class of applications. The experimental results have shown that the GPU based system demonstrated high speedup and it is therefore a good low cost solution for real-time scenarios such as in video surveillance systems.
As the processing power of set-top box (STB) devices continues to grow with each new product generation and multiple service operators directly manage millions of these devices through a dedicated broadband network, w...
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As the processing power of set-top box (STB) devices continues to grow with each new product generation and multiple service operators directly manage millions of these devices through a dedicated broadband network, we propose to harness this massive aggregate computational power to execute large-scale parallel applications. We present a prototype implementation of a heterogeneous distributed embedded system that combines a complete head-end cable system with a DOCSIS broadband network of STBs and an interoperable embedded implementation of Open MPI running on the STB operating system. We demonstrate the operations and performance of this system by reporting the experimental results that we obtained for the execution of various instances of Multiple Sequence Alignment, a parallel bioinformatics application. Based on these results we propose a new distributed embedded system architecture for highly-scalable intrusion-detection systems.
Images has very significant role in digital media. However, generally digital imaging generates large amounts of data it need to be compressed, without loss of relevant information or simply lossless compression. This...
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Images has very significant role in digital media. However, generally digital imaging generates large amounts of data it need to be compressed, without loss of relevant information or simply lossless compression. This paper presents a novel lossless image compression technique in spatial domain. The proposed algorithm divide the image into no. of blocks uses variable bits to store each block pixels. Calculation of variable bits is dependent on pixel values of each block. The advantage of proposed scheme, it is dependent upon pixels correlation with in a block. Experimental results show that our proposed algorithm gives better compression efficiency as compared to many existing state-of-the-art lossless spatial domain image compression algorithms such as LZW, RLE and DEFLATE used in TIFF, GIF and PNG formats.
Walsh-Hadamard transform (WHT) based multiplierless integer discrete cosine transform (IntDCT) has structural regularity even in short word length lifting coefficients. It, however, cannot apply to image coding withou...
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Walsh-Hadamard transform (WHT) based multiplierless integer discrete cosine transform (IntDCT) has structural regularity even in short word length lifting coefficients. It, however, cannot apply to image coding without the quantization part because WHT was implemented by only ±1 adder operations without the normalization scaling factors. Although we have already presented a normalized integer WHT (IntWHT) as its solution, it also has many adder operations. In this paper, using a two-dimensional (2-D) separable transform of one-dimensional (1-D) normalized WHT is applied to each lifting coefficient, we present a more simplified realization of normalized IntWHT with structural regularity for short word length lifting coefficients. Finally, in lossless-to-lossy image coding, IntDCT based on the proposed IntWHT is validated.
Recently, touchless multiview fingerprinting technology has been proposed as an alternative to overcome the intrinsic problems of traditional contact-based systems. Nevertheless, compression of this kind of signal has...
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Recently, touchless multiview fingerprinting technology has been proposed as an alternative to overcome the intrinsic problems of traditional contact-based systems. Nevertheless, compression of this kind of signal has not been fully evaluated and standardized. This paper investigates the comparative performance of several encoders for this data, namely WSQ, JPEG2000, H.264/AVC and MMP. Experimental results show that WSQ encoder, which is the current compression standard for contact-based fingerprints, is objectively outperformed by all others. In particular, MMP, which achieved the best results, outperforms WSQ by up to 4 dB.
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