Medical data are increasingly represented as volumes. The huge amount of data to be handled every day in clinical practice makes compression an unavoidable step in picture archiving and communication systems (PACS). W...
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Medical data are increasingly represented as volumes. The huge amount of data to be handled every day in clinical practice makes compression an unavoidable step in picture archiving and communication systems (PACS). We propose an object-based coding scheme for 3D datasets, providing full range quality scalability for each semantically meaningful region. An integer three-dimensional separable wavelet transform is performed on the whole volume. An analytic model based on hybrid ellipsoids is used to describe the different objects, which are then coded independently allowing random access. The adopted coding strategy is the 3D extension of the well known EZW approach. First results show that 3D EZW outperforms both JPEG and the bi-dimensional version of the same coding algorithm in both lossless and lossy modes.
Multimedia database systems are essential for the effective and efficient use of large collections of image data. The aim of such systems is to enable retrieval of images based on their contents. As part of our resear...
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Multimedia database systems are essential for the effective and efficient use of large collections of image data. The aim of such systems is to enable retrieval of images based on their contents. As part of our research in this area, we are building a prototype content-based image retrieval system called CHITRA. This uses a four-level data model, and we have defined a fuzzy object query language (FOQL) for this system. This system enables retrieval based on high-level concepts, such as "retrieve images of mountains and sunset". A problem faced in this system is the processing of complex queries such as "retrieve all images that have a similar color histogram and a similar texture to the given example image". Such problems have attracted research attention in recent times. R. Fagin (1996) has given an algorithm for processing such queries and provided a probabilistic upper bound for the complexity of the algorithm (which has been implemented in IBM's Garlic project). In this paper, we provide a theoretical (probabilistic) analysis of the expected cost of this algorithm. We propose a new multi-step query processing algorithm and prove that it performs better than Fagin's algorithm in all cases. Our algorithm requires fewer database accesses. We have evaluated both algorithms against an image database of 1000 images on our CHITRA system. We have used both color histogram and Gabor texture features. Our analysis is presented and the reported experimental results validate our algorithm (which has a significant performance improvement).
This paper describes a block processing unit in a single-chip MPEG-2 MP@ML video encoder LSI. The block processing unit executes algorithms such as a discrete cosine transform (DCT), a quantization, an inverse quantiz...
This paper describes a block processing unit in a single-chip MPEG-2 MP@ML video encoder LSI. The block processing unit executes algorithms such as a discrete cosine transform (DCT), a quantization, an inverse quantization, and an inverse discrete cosine transform (IDCT). A double-block pipeline scheme has been introduced to execute DCT and IDCT operations on the shared circuits. Using a time-multiplexed DCT/IDCT architecture, we achieve processing performance of 2.0 clk/pel. This architecture has 21% fewer transistors and 30% less power dissipation than a conventional one. The number of transistors of the block processing unit is 240 kTr which measures 7.7% of the total of the chip. By controlling the clock signal supply, power dissipation can be reduced to 43% which is about 400 mW at 3.3 v using a 0.35 μm triple-layer metal CMOS cell-base technology at 54 MHz.
In this paper we present our studies for implementing complex DSP and Telecom systems in FPGAs. We analyse suitability of FPGA device architectures for implementing complex algorithms. Here we use a viterbi algorithm ...
In this paper we present our studies for implementing complex DSP and Telecom systems in FPGAs. We analyse suitability of FPGA device architectures for implementing complex algorithms. Here we use a viterbi algorithm as a deeper case study. Different architectural strategies for implementations are discussed and analysed with the special emphasis on practical FPGA implementations. Speed performance, easy routability and minimisation of inter-chip communication are used as design criteria. viterbi decoder, constraint length seven, was designed and simulated with vHDL in Synopsys and Mentor tool environments and further implemented on four Xilinx 4028EX devices using trace-back based architecture. Also partitioning aspects of the decoding algorithm are presented and analysed.
In this paper, we present a parametric hybrid model used in the framework of multidimensional object representation, for applications to both object visualization and object-based data compression. Our model is define...
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In this paper, we present a parametric hybrid model used in the framework of multidimensional object representation, for applications to both object visualization and object-based data compression. Our model is defined as a set of hybrid ellipsoids suitable for both globally and locally deforming the reconstructed shape. Its new parameterization, as compared to classical techniques, allows us to preserve its analytical representation during the fitting process. It is fitted to the object contours by means of a genetic algorithm minimizing a mean-square error criterion. Several criteria are proposed and discussed according to the stability of the optimization process, as well as the ability to efficiently initialize the model parameters. Finally, fitting results are presented for 2D and 3D data and different applications are proposed.
The digital classification techniques produce images with noise and not so well defined interregional boundaries. In order to eliminate these defects and to enhance the quality of thematic maps post processing algorit...
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The digital classification techniques produce images with noise and not so well defined interregional boundaries. In order to eliminate these defects and to enhance the quality of thematic maps post processingalgorithms are generally applied. The IRS sensor LISS-data is used in this study and the information fusion method is applied to validate its utility for data classification. The two image products obtained after maximum likelihood classification and Sobel's filter are merged using HIS transformation. The region growing algorithm available in literature is applied by following the conditions used in stopping the region-growing process.
We present a new, mixed-radix (radix-4/radix-2) CORDIC algorithm for vector rotation and an efficient, pipelined implementation in Atmel's AT40K technology. Using only 3 radix-4 stages and one radix-2 stage, a sam...
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We present a new, mixed-radix (radix-4/radix-2) CORDIC algorithm for vector rotation and an efficient, pipelined implementation in Atmel's AT40K technology. Using only 3 radix-4 stages and one radix-2 stage, a sample rotator using this new algorithm achieves in 4 clock cycles the same accuracy that a conventional (radix-2) rotator would achieve in 7 cycles, while each cycle is almost the same speed as that of a conventional rotator. This sample rotator attains 12 bits of accuracy externally, while internally 17 bits of accuracy is kept. This rotator fits in an AT40K30, and has a worst-case delay of up to 55.9 ns per stage (speed level 2) and a typical delay of 35 ns including output buffers. CORDIC rotators can be used to improve the efficiency of many important DSP functions such as transforms, modulation and demodulation, motion sensing and control, and imageprocessing.
The conversion of newspaper pages into digital resources is an important task that greatly contributes to the preservation of and access to newspaper archives. In this paper, an integrated methodology is presented for...
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The conversion of newspaper pages into digital resources is an important task that greatly contributes to the preservation of and access to newspaper archives. In this paper, an integrated methodology is presented for segmenting newspaper pages and identifying newspaper articles. In the first stage, a succession of imageprocessing and document analysis algorithms is employed for segmenting newspaper page images into various objects (text, images and drawings, titles). A rule based approach is subsequently applied to the objects identified during the page segmentation phase for reconstructing individual articles. Experimental results, obtained from a large testbed of old newspaper issues, are presented which clearly demonstrate the applicability of our integrated approach to successful newspaper page segmentation and identification of newspaper articles.
The paper presents and evaluates the design and the implementation of a self-checking neural system for photon event identification in intensified charge-coupled device detectors. The neural approach reveals more effe...
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The paper presents and evaluates the design and the implementation of a self-checking neural system for photon event identification in intensified charge-coupled device detectors. The neural approach reveals more effective than classical algorithmic approaches thanks to its learning through example ability. Implementation is accomplished by SRAM-based FPGAs, which have generated increasing interest in the space community. The adoption of suitable on-line fault detection techniques is illustrated taking into account in a specific way SEU induced faults. The techniques are based on AN coding, particularly 3N coding, which constitutes a reasonable trade-off between circuit complexity and computational delay. Estimations of circuit area overhead and fault coverage are reported.
The objective in the scenic beauty estimation (SBE) problem is to develop an automatic classification algorithm that matches human subjective ratings. algorithms such as principal components analysis (PCA) and decisio...
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The objective in the scenic beauty estimation (SBE) problem is to develop an automatic classification algorithm that matches human subjective ratings. algorithms such as principal components analysis (PCA) and decision trees (DT) have been applied to this problem with limited success, motivating our search for a better classifier. Since this is obviously a nonlinear classification problem, we applied two nonlinear techniques: independent component analysis (ICA) and support vector machines (SvMs). We evaluated these algorithms on a standard, publicly available data set using a variety of combinations of features. The optimally configured ICA and SvM systems achieved misclassification rates of 33.4% and 32.2% respectively. This is a significant improvement over the best results previously reported on this task: 36.6% for PCA and 43% for DT. Since ambiguity in the features space is a significant problem in this application, these results validate the effectiveness of nonlinear classification techniques.
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