image compression is increasingly employed in applications such as medical imaging, for reducing data storage requirement, and Internet video transmission, to effectively increase channel bandwidth. Similarly, militar...
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ISBN:
(纸本)0819454990
image compression is increasingly employed in applications such as medical imaging, for reducing data storage requirement, and Internet video transmission, to effectively increase channel bandwidth. Similarly, military applications such as automated target recognition (ATR) often employ compression to achieve storage and communication efficiencies, particularly to enhance the effective bandwidth of communication channels whose throughput suffers, for example, from overhead due to error correction/detection or encryption. In the majority of cases, lossy compression is employed due the resultant low bit rates (high compression ratio). However, lossy compression produces artifacts in decompressed imagery that can confound ATR processes applied to such imagery, thereby reducing the probability of detection (Pd) and possibly increasing the rate or number of false alarms (Rfa or Nfa). In this paper, the authors' previous research in performance measurement of compression transforms is extended to include (a) benchmarking algorithms and software tools, (b) a suite of error exemplars that are designed to elicit compression transform behavior in an operationally relevant context, and (c) a posteriori analysis of performance data. The following transforms are applied to a suite of 64 error exemplars: visual Pattern imagecoding (VPIC [1]), Vector Quantization with a fast codebook search algorithm (VQ [2,3]), JPEG and a preliminary implementation of JPEG 2000 [4,5], and EBLAST [6-8]. compression ratios range from 2:1 to 200:1, and various noise levels and types are added to the error exemplars to produce a database of 7,680 synthetic test images. Several global and local (e.g., featural) distortion measures are applied to the decompressed test imagery to provide a basis for rate-distortion and rate-performance analysis as a function of noise and compression transform type.
The first part of the article gives a brief examination of the state of art in terms of methodologies, hardware available and algorithms used in space applications. Particular emphasis is given to the lossless algorit...
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ISBN:
(纸本)0819441899
The first part of the article gives a brief examination of the state of art in terms of methodologies, hardware available and algorithms used in space applications. Particular emphasis is given to the lossless algorithms used and their characterization. In the second part a more detailed analysis, in terms of data entropy, is presented. At the end the preliminary results in the determination of compressibility of the file will be presented.
This Volume 4793 of the conference proceedings contains 34 papers. Topics discussed include mathematics of data/image coding, compression, and encryption and security, remote sensing and communication and compressive ...
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This Volume 4793 of the conference proceedings contains 34 papers. Topics discussed include mathematics of data/image coding, compression, and encryption and security, remote sensing and communication and compressive processing.
The suggested device includes a spatial light modulator (SLM) allowing varying the polarization state of an input illumination source. Attached to the SLM a sub wavelength grating is placed per each pixel of the devic...
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ISBN:
(纸本)0819445606
The suggested device includes a spatial light modulator (SLM) allowing varying the polarization state of an input illumination source. Attached to the SLM a sub wavelength grating is placed per each pixel of the device. This grating is used to encode the input information. The decoding is done by another sub wavelength grating. When the two gratings are attached a variation of the energetic efficiency between the two polarization states occurs. The polarization ratio encrypts the spatial information strewn. The sub wavelength grating are hard to copy and thus high encryption capability is obtained.
Lattice independence and strong lattice independence of a set of pattern vectors are fundamental mathematical proper-ties that lie at the core of pattern recognition applications based on lattice theory. Specifically,...
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ISBN:
(纸本)9780819468482
Lattice independence and strong lattice independence of a set of pattern vectors are fundamental mathematical proper-ties that lie at the core of pattern recognition applications based on lattice theory. Specifically, the development of morphological associative memories robust to inputs corrupted by random noise are based on strong lattice independent sets, and real world problems, such as, autonomous endmember detection in hyperspectral imagery, use auto-associative morphological memories as detectors of lattice independence. In this paper, we present a unified mathematical framework that-develops the relationship between different notions of lattice independence currently used in the literature. Computational procedures are provided to test if a given set of pattern vectors is lattice independent or strongly lattice independent;in addition, different techniques are fully described that can be used to generate sets of vectors with the aforementioned lattice properties.
In this paper we propose a novel method for computing JPEG quantization matrices based on desired mean square error, avoiding the classical trial and error procedure. First, we use a relationship between a Laplacian s...
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ISBN:
(纸本)0819429112
In this paper we propose a novel method for computing JPEG quantization matrices based on desired mean square error, avoiding the classical trial and error procedure. First, we use a relationship between a Laplacian source and its quantization error when uniform quantization is used in order to find a model for uniform quantization error. Then we apply this model to the coefficients obtained in the JPEG standard once the image to be compressed has been transformed by the discrete cosine transform. This allows us to compress an image using JPEG standard under a global MSE (or PSNR) constraint and a set of local constraints determined by JPEG standard and visual criteria. Simulations show that our method generates better quantization matrices than the classical method of scaling the JPEG default quantization matrix, with a cost lower than the coding, decoding and error measuring procedure.
In this paper an attack strategy on the dataencryption Standard (DES) that is different from the existing ones is developed. The attack strategy is based on a theorem proved by the author, called LR theorem. The atta...
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In this paper an attack strategy on the dataencryption Standard (DES) that is different from the existing ones is developed. The attack strategy is based on a theorem proved by the author, called LR theorem. The attack can be done by means of a personal computer, i.e. a Pentium IV based machine. Obviously, more information than a sample of plaintext and ciphertext is required. However, this additional requirement is reduced to a minimum of just 24 bits. The LR theorem uncovers 16 trapdoors of which 2 are of importance. With this knowledge, an attack on Triple-DES can be performed using the aforementioned personal computer. A simple solution to this kind of attack is proposed, preserving the complexity of the Triple-DBS, 2112.
Advances in network communications have necessitated secure local-storage and transmission of multimedia content. In particular, military networks need to securely store sensitive imagery which at a later stage may be...
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Advances in network communications have necessitated secure local-storage and transmission of multimedia content. In particular, military networks need to securely store sensitive imagery which at a later stage may be transmitted over bandwidth-constrained wireless networks. This work investigates compression efficiency of JPEG and JPEG 2000 standards for encrypted images. An encryption technique proposed by Kuo et al. in [4] is employed. The technique scrambles the phase spectrum of an image by addition of the phase of an all-pass pre-filter. The post-filter inverts the encryption process, provided the correct pseudo-random filter coefficients are available at the receiver. Additional benefits of pre/post-filter encryption include the prevention of blocking effects and better robustness to channel noise [4]. Since both JPEG and JPEG 2000 exploit spatial and perceptual redundancies for compression, pre/post-filtered (encrypted) images are susceptible to compression inefficiencies. The PSNR difference between the unencrypted and pre/post-filtered images after decompression is determined for various compression rates. compression efficiency decreases with an increase in compression rate. For JPEG and JPEG 2000 compression rates between 0.5 to 2.5 bpp, the difference in PSNR is negligible. Partial encryption is proposed wherein a subset of image phase coefficients are scrambled. Due to the phase sensitivity of images, even partial scrambling of the phase information results in unintelligible data. The effect of compression on partially encrypted images is observed for various bit-rates. When 25% of image phase coefficients are scrambled, the JPEG and JPEG 2000 compression performance of encrypted images is almost similar to that of unencrypted images for compression rates in the 0.5 to 3.5 bpp range.
Earth observation missions have recently attracted a growing interest from the scientific and industrial communities, mainly due to the large number of possible applications capable to exploit remotely sensed data and...
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ISBN:
(纸本)0819441899
Earth observation missions have recently attracted a growing interest from the scientific and industrial communities, mainly due to the large number of possible applications capable to exploit remotely sensed data and images. Along with the increase of market potential, the need arises for the protection of the image products from non-authorized use. Such a need is a very crucial one even because the Internet and other public/private networks have become preferred means of data exchange. A crucial issue arising when dealing with digital image distribution is copyright protection. Such a problem has been largely addressed by resorting to watermarking technology. A question that obviously arises is whether the requirements imposed by remote sensing imagery are compatible with existing watermarking techniques. On the basis of these motivations, the contribution of this work is twofold: i) assessment of the requirements imposed by the characteristics of remotely sensed images on watermark-based copyright protection ii) analysis of the state-of-the-art, and performance evaluation of existing algorithms in terms of the requirements at the previous point.
In the paper we present comparison of three advanced techniques for video compression. Among them 3D Embedded Zerotree Wavelet (EZW) coding, recently suggested Optimal imagecoding using Karhunen-Loeve (KL) transform ...
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In the paper we present comparison of three advanced techniques for video compression. Among them 3D Embedded Zerotree Wavelet (EZW) coding, recently suggested Optimal imagecoding using Karhunen-Loeve (KL) transform (OICKL) and new algorithm of video compression based on 3D EZW coding scheme but with using KL transform for frames decorrelation (3D-EZWKL). It is shown that OICKL technique provides the best performance and usage of KL transform with 3D-EZW coding scheme gives better results than just usage of 3D-EZW algorithm.
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