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Time-frequency analysis for radar classification of land-mine images

JOURNAL OF ELECTRONIC IMAGING 2007年第3期16卷 033014.1-033014.12页

作者： Wong, David C. Nguyen, Lam H. Gaunaurd, Guillermo C. Army Res Lab Adelphi MD 20783 USA

We use time-frequency (t-f) analysis techniques to examine the echo returns present in synthetic aperture radar (SAR) images of land-mine fields. A flying platform illuminates a mine field containing various types of mines and "confusers," with an ultra-wideband radar. A number of familiar time-frequency distributions are used to inspect the various possible mine locations above and below the ground surface. The 2-dimensional plots generated by these distributions offer a larger variety of features and clues that facilitate the discrimination of each mine type from the others and from possible "confusers." Conclusions emerge that confirm that the pseudo-Wigner-Ville and the Choi-Williams distributions provide the best discrimination results, as was pointed out in earlier work. Larger mines such as the ones denoted here as "type 1" are the easiest to discriminate. Comparison of mines to clutter objects ("confusers') shows that such objects are clearly distinguishable from all the present metal mines. (c) 2007 SPIE and IS&T.

关键词： Mining Synthetic aperture radar Time-frequency analysis Radar Image classification Soil science algorithm development Inspection Metals Spatial resolution

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Sensitivity analysis of different sensing strategies for electrical impedance imaging of two-phase flows

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JOURNAL OF ELECTRONIC IMAGING 2001年第3期10卷 641-645页

作者： Figueroa, TP Seleghim, P Univ Sao Paulo Escola Engn Sao Carlos Dept Engn Mecan Nucleo Engn Term & Fluidos BR-13566590 Sao Carlos SP Brazil

Due to practical considerations, electrical fields and other soft field sensing techniques are convenient to use in process tomography applications. However, most of the reconstruction algorithms were first developed for hard sensing fields that approximate soft fields only in the situation of low electrical contrast. A less restrictive reconstruction method can be developed by refining the qualitative images of a direct imaging probe, but the boundary measurements must be sensitive to changes in the distribution of the electrical properties of the flow. This paper addresses the issue and presents a sensitivity analysis of different excitation strategies and their applicability in a reconstruction algorithm such as described above. Results confirm that classical excitation strategies suffer from a major lack of sensitivity and that new ones must be developed, possibly based on the optimization of the excitation profiles or on multisensing techniques. (C) 2001 SPIE and IS&T.

关键词： Electrodes Tomography Numerical simulations Analytical research Reconstruction algorithms Standards development algorithm development Automatic control Image processing Surface plasmons

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Block-matching algorithm based on dynamic adjustment of search window for low bit-rate video coding

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JOURNAL OF ELECTRONIC IMAGING 1998年第3期7卷 571-577页

作者： Oh, HS Lee, HK Korea Adv Inst Sci & Technol Dept Comp Sci Taejon 305701 South Korea

A dynamic search window adjustment for block-matching algorithm (BMA) based on the block similarity is presented to reduce the computational complexity of full search BMA. The adjustment of the size of the search window is performed in three steps: (1) set a new search origin based on the block similarity and the displaced block difference (DBD), (2) adjust the size of search window in inverse proportion to block similarity, and (3) update the thresholds for accommodation to a given image sequence. The technique can be easily applied to full search BMA and several fast search algorithms to get more efficiency and to reduce a possibility of falling into a local minimum. Experimental results show that the proposed technique has a good MSE performance and reduces the number of search points substantially. (C) 1998 SPIE and IS&T. [S1017-9909(98)02303-4].

关键词： Video Image segmentation Video coding Image processing algorithms and systems Distortion algorithm development Motion estimation Computer science Computer simulations

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Developing MSA algorithm by New Fitness-Distance-Balance Selection Method to Optimize Cascade Hydropower Reservoirs Operation

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WATER RESOURCES MANAGEMENT 2021年第1期35卷 385-406页

作者： Sharifi, Mohammad Reza Akbarifard, Saeid Qaderi, Kourosh Madadi, Mohamad Reza Shahid Chamran Univ Ahvaz Fac Water & Environm Engn Dept Hydrol & Water Resources Ahvaz Iran Shahid Chamran Univ Ahvaz Fac Water & Environm Engn Dept Hydrol & Water Resources Water Resources Engn Ahvaz Iran Shahid Bahonar Univ Kerman Dept Water Engn Fac Agr Kerman Iran Univ Jiroft Dept Water Engn Fac Agr Jiroft Iran

Optimal operation of cascade hydropower reservoirs is a complex high-dimensional engineering problem. Developing an appropriate model to solve such problems requires an efficient search method proportional to the dimensions of the problem. Accordingly, this research employed the new fitness-distance-balance (FDB) selection method in the moth swarm algorithm (MSA) to achieve promoted FDB-MSA with a high performance in solving complex large-scale problems. To ensure the efficiency of the developed algorithm, five benchmark functions of Shekel, Six-Hump Camel, McCormick, Goldstein-Price and Rosenbrock were used. Then, the FDB-MSA was used for optimization of hydropower generation of a real five-reservoir system along Karun River at Iran. This is the largest cascade reservoir system in Iran, which supplies more than 90% of the country's hydropower demand. The results of the developed algorithm were compared with those of genetic algorithm (GA) and particle swarm optimization (PSO) algorithm. It was found that the FDB-MSA could successfully increase the hydropower generation by 59.5% (6724 GW) compared to the actual generation of energy over a 180-months operational period. The corresponding values for PSO and GA algorithms were 54.3% and 9.2% respectively. In addition, the results revealed the superiority of FDB-MSA to GA and PSO, so that, it demonstrated the smallest difference (3.41%) between nominal and optimal power generation compared to the PSO (6.58%) and GA (33.89%).

关键词： Selection methods algorithm development Renewable energy Consecutive dams Real case study

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Analysis and generalization of Retinex by recasting the algorithm in wavelets

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JOURNAL OF ELECTRONIC IMAGING 2004年第1期13卷 93-99页

作者： Rising, HK Sony Corp Network & Software Technol Ctr Amer Media Proc Div San Jose CA 95134 USA

The Retinex algorithm presents an interesting mix of a locally connected iterative algorithm and a multiresolution analysis of the image. By recasting the algorithm, using wavelets, the behavior of the algorithm comes to light. This allows generalizations to be proposed, by changes in both the multiresolution structure and the iterative update structure. (C) 2004 SPIE and IST.

关键词： Wavelets Diffusion Wavelet transforms Reconstruction algorithms Image processing Image analysis Wave propagation algorithm development Image resolution Raster graphics

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Automatic call number localization in color book images

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JOURNAL OF ELECTRONIC IMAGING 2005年第4期14卷 043017.1-043017.6页

作者： Hu, XF Zhou, Y Ye, QT Shanghai Jiao Tong Univ Sch Mech Engn Shanghai 200030 Peoples R China

An algorithm for automatic localization of call numbers embedded in book images is proposed. The algorithm first detects potential character pixels by computing the difference and the position relation between the maximum and minimum gradient in a local window. These pixels are combined to form connected components ( CCs). Then, CC-based filtering based on the geometry and shape information is performed to eliminate some nontext components, and the retained components are grouped into text lines candidates. Finally, the call number is selected from the text candidates by using a multilayer perceptron ( MLP) classifier. Tests are performed on a set of the images acquired under the different conditions, and experimental results prove that the proposed method is effective. (c) 2005 SPIE and IS&T.

关键词： Image segmentation Video Feature extraction Image filtering algorithm development Image processing Chromium Detection and tracking algorithms Neural networks RGB color model

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RECOGNITION OF A LOW-RESOLUTION DOCUMENT CONSISTING OF KOREAN AND ENGLISH CHARACTERS

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JOURNAL OF ELECTRONIC IMAGING 1995年第2期4卷 161-171页

作者： HAM, YK DOH, SY CHUNG, HK KIM, WS PARK, RH Sogang Univ. (South Korea)

We propose an efficient algorithm that recognizes handwritten Korean and English characters in a low-resolution document. For a user-friendly input system for low-resolution documents consisting of two different sets of characters obtained by a facsimile or scanner, we propose a document-recognition algorithm utilizing several effective features (partial projection, the number of cross points, and distance features) and the membership function of the fuzzy set theory. Via computer simulation with several test documents, we show the effectiveness of the proposed recognition algorithm for both printed and handwritten and Korean and English characters in a low-resolution document.

关键词： Detection and tracking algorithms Optical character recognition Fuzzy logic Visualization Scanners Evolutionary algorithms Binary data algorithm development Distortion Head

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Automated power spectrum analysis of low-latitude ionospheric scintillations recorded using software GNSS receiver

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GPS SOLUTIONS 2020年第1期24卷 1-12页

作者： Sethi, Himanshu Sekhar Dashora, N. Natl Atmospher Res Lab Tirupati 517112 Andhra Pradesh India

The impact of equatorial plasma bubbles (EPBs) on signals from navigation satellites has remained unpredictable. EPBs could be tracked to some extent with prior knowledge of zonal drift and other important parameters associated with scintillations for a given local time. Aiming for this, we analyze high-rate carrier-to-noise (C/N0) GPS L1 signals recorded using a software GNSS receiver during February-April 2015. In the absence of an automated algorithm in this domain, a new algorithm is developed for estimation of power spectra, Fresnel frequency, noise floor, spectral slope, and ionospheric zonal irregularity drift using per minute scintillation patches. Importantly, since multipath and scintillation can co-occur at lower elevation angles, a new criterion for multipath identification and separation from scintillation and fading is defined as part of the automated algorithm. The C/N0 data above the threshold value of 0.17 of the scintillation index (S4) are only considered by this algorithm. Details of the approach and method are presented with example sets. Results for the estimated zonal drifts, spectral index, and decorrelation length of the post-sunset irregularities are illustrated. Variations in these parameters are presented along with local time, latitude, and longitude of the ionospheric pierce points. The drastic variations that a GPS user and a forecaster would encounter in equatorial latitudes are explained in terms of the challenge they pose. This study is probably the first in terms of automation of the process that shall be highly useful for single-station scintillation observations.

关键词： Equatorial scintillation Power spectrum Spectral index Multipath algorithm development Zonal drift GNSS

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Practical image registration concerns overcome by the weighted and filtered mutual information metric

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JOURNAL OF ELECTRONIC IMAGING 2012年第2期21卷 023029-1-023029-17页

作者： Keane, Tommy P. Saber, Eli Rhody, Harvey Savakis, Andreas Raj, Jeffrey Rochester Inst Technol Chester F Carlson Ctr Imaging Sci Rochester NY 14623 USA Rochester Inst Technol Dept Elect & Microelect Engn Rochester NY 14623 USA Rochester Inst Technol Dept Comp Engn Rochester NY 14623 USA Lenel Syst Int Inc Pittsford NY 14534 USA

Contemporary research in automated panorama creation utilizes camera calibration or extensive knowledge of camera locations and relations to each other to achieve successful results. Research in image registration attempts to restrict these same camera parameters or apply complex point-matching schemes to overcome the complications found in real-world scenarios. This paper presents a novel automated panorama creation algorithm by developing an affine transformation search based on maximized mutual information (MMI) for region-based registration. Standard MMI techniques have been limited to applications with airborne/satellite imagery or medical images. We show that a novel MMI algorithm can approximate an accurate registration between views of realistic scenes of varying depth distortion. The proposed algorithm has been developed using stationary, color, surveillance video data for a scenario with no a priori camera-to-camera parameters. This algorithm is robust for strict-and nearly-affine-related scenes, while providing a useful approximation for the overlap regions in scenes related by a projective homography or a more complex transformation, allowing for a set of efficient and accurate initial conditions for pixel-based registration. (C) 2012 SPIE and IS&T. [DOI: 10.1117/***.21.2.023029]

关键词： Principal component analysis Wavelets Databases Facial recognition systems Detection and tracking algorithms Feature extraction Image registration algorithm development Autoregressive models Cameras

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Spaced-based data compression issues

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JOURNAL OF ELECTRONIC IMAGING 1999年第3期8卷 301-310页

作者： Saghri, JA Tescher, AG Reagan, JT Kuwait Univ Dept Elect & Comp Engn Kuwait 13060 Kuwait Lockheed Martin Mission Syst Interact Technol Ctr Sunnyvale CA 94089 USA VLSI Technol Inc San Jose CA 95131 USA

Some key issues related to space-based compression design are discussed. Various system considerations as well as potential compression options are also presented. A brief overview of a previously reported robust lossy transform coding algorithm is given followed by a study of its performance sensitivities. These sensitivities include (1) performance sensitivity to commonly observed anomalies in the data including band misalignment and dead/saturated pixels, (2) impact of geometric distortion (processed versus unprocessed data) on compression performance, (3) performance sensitivity to different grouping of bands for spectral decorrelation, and (4) impact of compression on spectral fidelity. In addition, the impact of compression on the results of exploitation of environmental data including automated cloud study will be considered. It is shown that preprocessing to correct any geometric distortion noticeably improves the compression performance. Different groupings of bands also influence the performance. The loss of spectral fidelity, measured by the deviation from the original correlation coefficient matrix, is very insignificant regardless of the image and the coding bit rates. For the available bit rate, it is possible to trade off the compression-induced error between the spectral and spatial resolutions. In the implementation scenarios investigated, it was found that compression at rates approaching 16:1 has a minor impact on the exploitation and assessment of the ultimately derived automated cloud analysis. Additional work is needed to evaluate the impact of compression on other products, such as sea surface temperature. The results to date suggest that lossy compression may play a role in the efficient transmission of environmental information and in its subsequent exploitation. (C) 1999 SPIE and IS&T. [S1017-9909(99)00103-8].

关键词： Image compression Clouds Data compression algorithm development Data modeling Image processing Spatial resolution Distortion Image quality standards Spectral resolution

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