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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： J.M. Villa S.L. Cruz-Pol S.M. Sekelsky Electrical and Computer Engineering Department University of Puerto Rico Mayaguez Puerto Rico Microwave Remote Sensing Laboratory University of Massachusetts Amherst Amherst MA USA

The minimum detectable radar reflectivity (dBZemin) is computed for the University of Massachusetts' 33 GHz/95 GHz Cloud Profiling Radar System (CPRS) under humid tropical conditions. Extinction by water vapor and oxygen are calculated for a horizontally stratified atmosphere as a function of range and scan angle for both radar frequencies. Combined radiosonde and dual-frequency microwave radiometer measurements are used to model radar signal extinction for the Maritime Continent Thunderstorm Experiment (MCTEX), which was conducted in northern Australia. These data are compared with CPRS radar measurements to evaluate the performance of both frequencies for sensing clouds and precipitation versus elevation angle.

关键词： Millimeter wave radar Frequency Radar measurements Radar detection Reflectivity Cloud computing Atmosphere Microwave radiometry Atmospheric measurements Microwave measurements

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3-D Bayesian ultrasound breast image segmentation using the EM/MPM algorithm

3-D Bayesian ultrasound breast image segmentation using the ...

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IEEE International Symposium on Biomedical Imaging

作者： L.A. Christopher E.J. Delp C.R. Meyer P.L. Carson Video and Image Processing Laboratory School of Electrical and Computer Engineering Purdue University West Lafayette IN USA Department of Radiology University of Michigan Ann Arbor MI USA

In this paper, ultrasound breast image segmentation is improved by using the volumetric data available in neighboring slices. The new algorithm extends the EM/MPM framework to 3D by including pixels from neighboring frames in the Markov Random Field (MRF) clique. In addition, this paper describes a unique linear cost factor introduced in the optimization loop to compensate for the attenuation common to ultrasound images.

关键词： Bayesian methods Ultrasonic imaging Breast image segmentation Markov random fields Magnetic resonance imaging Acoustic noise image processing Cost function Attenuation

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A recursive shape error concealment algorithm

A recursive shape error concealment algorithm

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IEEE International Conference on image processing

作者： Xiaohuan Li A.K. Katsaggelos G.M. Schuster Image and Video Processing Laboratory Department of Electrical and Computer Engineering Northwestern University Evanston IL USA Abteilung Ekktechnik Hochschule für Technik Rapperswil Switzerland

The encoding of shape information is a distinguishing feature of MPEG-4. In error prone communication networks, it is important and efficient to conceal shape errors spatially, so as to avoid propagation of errors in the video frames. The proposed system first defines the missing area's four rectangular neighbors. It then detects in the neighbors the lines that intersect the borders and redefines them in a geometric coordinate system. These lines are paired under some optimization objective so that they connect smoothly in the missing area. Each pair is extrapolated and corrected recursively until a close curve is formed. Test results on various sequences under various error rates are presented and compared with other shape concealment methods.

关键词： Shape computer errors Decoding Streaming media Motion compensation image coding MPEG 4 Standard Laboratories Communication networks Testing

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Enhancing the performance of personal identity authentication systems by fusion of face verification experts

Enhancing the performance of personal identity authenticatio...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： J. Kittler M. Ballette J. Czyz F. Roli L. Vandendorpe Centre for Vision Speech and Signal Processing University of Surrey Guildford UK Department of Electrical Engineering University of Cagliari Italy Communications and Remote Sensing Laboratory Universite catholique de Louvain Belgium

We investigate the behavior knowledge space method (see Xu, L. et al., IEEE Transactions SMC, vol.22, no.3, p.418-35, 1992) and decision templates method (see Kuncheva, L. et al., Pattern Recognition, vol.34, p.299-314, 2001) of classifier fusion in the context of face verification. The study involves six experts which are not only correlated, but also their performance levels differ by as much as a factor of three. Through extensive experiments on the XM2VTS database using the Lausanne protocol, we found that the behavior knowledge space fusion strategy achieved consistently better results than the decision templates method. Most importantly, it exhibited quasi monotonic behavior as the number of experts combined increased. This is a very important conclusion, as it means that the performance of the multimodal system is not degraded by adding experts.

关键词： Authentication Biometrics Face detection Protocols image databases Error analysis Expert systems Speech processing Biomedical signal processing remote sensing

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An optimal shape encoding scheme using skeleton decomposition

An optimal shape encoding scheme using skeleton decompositio...

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IEEE Workshop on Multimedia Signal processing

作者： Haohong Wang G.M. Schuster A.K. Katsaggelos T.N. Pappas Image and Video Processing Laboratory Department of Electrical and Computer Engineering NorthWestern University Evanston IL USA Abteilung Elektrotechnik Hochschnle für Technik und Wirtschaft Rapperswil Switzerland

This paper presents an operational rate-distortion (ORD) optimal approach for skeleton-based boundary encoding. The boundary information is first decomposed into skeleton and distance signals, by which a more efficient representation of the original boundary results. Curves of arbitrary order are utilized for approximating the skeleton and distance signals. For a given bit budget for a video frame, we solve the problem of choosing the number and location of the control points for all skeleton and distance signals and for all boundaries within a frame, so that the overall distortion is minimized. The problem is solved with the use of Lagrangian relaxation and a shortest path algorithm in a 4D directed acyclic graph (DAG) we propose. By defining a path selection pattern, we reduce the computational complexity of the 4D DAG shortest path algorithm from O(N/sup -5/) to O(N/sup -4/), where N is the number of admissible control points for a skeleton. A suboptimal solution is also presented for further reducing the computational complexity of the algorithm to O(N/sup -2/). The proposed algorithm outperforms experimentally other competing algorithms.

关键词： Encoding Skeleton Lagrangian functions Computational complexity MPEG 4 Standard Shape control Approximation error image coding Distortion Standardization

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Normal mammogram classification based on regional analysis

Normal mammogram classification based on regional analysis

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Midwest Symposium on Circuits and Systems (MWSCAS)

作者： Yajie Sun C.F. Babbs E.J. Delp Video and Image Processing Laboratory School of Electrical and Computer Engineering Purdue University West Lafayette IN USA Department of Basic Medical Sciences School of Veterinary Medicine Purdue University West Lafayette IN USA

The majority of screening mammograms are normal. It will be beneficial if a detection system is designed to help radiologists readily identify normal regions of mammograms. In this paper, we will present a binary tree classifier based on the use of global features extracted from different levels of a 2-D Quincunx wavelet decomposition of normal and abnormal regional images. This classifier is then used to classify whether an entire whole-field mammogram is normal. This approach is fundamentally different from other approaches that identify a particular abnormality in that is independent of the particular type of abnormality.

关键词： Feature extraction Cancer detection Classification tree analysis Mammography Lesions Biomedical imaging Decision trees image databases Sun image processing

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Three-dimensional television using optical scanning holography

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Journal of Information Display 2002年第3期3.0卷 12-16页

作者： Poon, Ting-Chung Optical Image Processing Laboratory Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University (Virginia Tech) Blacksburg VA 24061 United States

We first review a real-time three-dimensional (3-D) holographic recording technique called optical scanning holography (OSH) and discuss holographic reconstruction using spatial light modulators (SLMs). We then present how the overall system can be used for 3-D holographic television (TV) display with a wide-angle view of a 3-D image, and address some of the issues encountered. Finally, we suggest some techniques to alleviate the issues encountered in such a 3-D holographic TV system. © 2002 Taylor & Francis Group, LLC.

关键词： Holographic information reduction Holographic TV system Optical scanning holography Twin-image elimination

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Landsat-7 ETM+ radiometric stability and absolute calibration

Landsat-7 ETM+ radiometric stability and absolute calibratio...

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Sensors, Systems, and Next-Generation Satellites VI

作者： Markham, Brian L. Barker, John L. Barsi, Julia A. Kaita, Ed Thome, Kurds J. Helder, Dennis L. Palluconi, Frank D. Schott, John R. Scaramuzza, Pat Landsat Project Science Office Goddard Space Flight Center/NASA Greenbelt MD United States Remote Sensing Group Optical Sciences Center University of Arizona Tucson AZ 85721 United States Department of Electrical Engineering South Dakota State University Brookings SD 57007 United States NASA Jet Propulsion Laboratory M/S 183-501 4800 Oak Grove Drive Pasadena CA 91109 United States Center for Imaging Science Rochester Institute of Technology 74 Lomb Memorial Dr. Rochester NY 14623 United States Landsat- 7 Image Assessment System EROS Data Center USGS 47914 252nd St. Sioux Falls SD 57198 United States NASA/GSFC Code 923 Greenbelt MD 20771 United States

Launched in April 1999, the Landsat-7 ETM+ instrument is in its fourth year of operation. The quality of the acquired calibrated imagery continues to be high, especially with respect to its three most important radiometric performance parameters: reflective band instrument stability to better than ±1%, reflective band absolute calibration to better than ±5%, and thermal band absolute calibration to better than ±0.6 K. The ETM+ instrument has been the most stable of any of the Landsat instruments, in both the reflective and thermal channels. To date, the best on-board calibration source for the reflective bands has been the Full Aperture Solar Calibrator, which has indicated changes of at most -1.8% to -2.0% (95% C.I.) change per year in the ETM+ gain (band 4). However, this change is believed to be caused by changes in the solar diffuser panel, as opposed to a change in the instrument's gain. This belief is based partially on ground observations, which bound the changes in gain in band 4 at -0.7% to +1.5%. Also, ETM+ stability is indicated by the monitoring of desert targets. These image-based results for four Saharan and Arabian sites, for a collection of 35 scenes over the three years since launch, bound the gain change at -0.7% to +0.5% in band 4. Thermal calibration from ground observations revealed an offset error of +0.31 W/m 2 sr um soon after launch. This offset was corrected within the U. S. ground processing system at EROS Data Center on 21-Dec-00, and since then, the band 6 on-board calibration has indicated changes of at most +0.02% to +0.04% (95% C.I.) per year. The latest ground observations have detected no remaining offset error with an RMS error of ±0.6 K. The stability and absolute calibration of the Landsat-7 ETM+ sensor make it an ideal candidate to be used as a reference source for radiometric cross-calibrating to other land remote sensing satellite systems.

关键词： Radiometry

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Discrimination measures for target classification

Discrimination measures for target classification

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Shao-Shan Chiang Chein-I Chang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA

Target detection does not necessarily yield target classification since the detected targets may belong to different classes and cannot be differentiated one from another by target detection. This often occurs when no prior target knowledge is available. In order to resolve this dilemma, four measures are proposed for target discrimination in this paper, two of which are designed based on the Bhattacharyya distance and the other two are derived from the concept of the matched filter. They will be used to cluster the detected anomalies into different types of targets in an unsupervised manner. These four target discrimination measures take advantage of the second-order statistics of the image data to account for sample spectral correlation. Consequently, they all outperform the commonly used single-pixel based similarity measures, such as spectral angle mapper (SAM), Euclidean distance. An experiment-based quantitative study is conducted for their performance evaluation. Interestingly, all these four measures perform very similarly.

关键词： Covariance matrix Matched filters Signal processing Object detection remote sensing image processing Laboratories computer science Statistics Euclidean distance

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Real-time processing of an unsupervised constrained linear spectral unmixing algorithm

Real-time processing of an unsupervised constrained linear s...

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IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： D.C. Heinz Chein-I Chang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA

Most spectral unmixing techniques require complete a priori knowledge of spectral endmembers in an image scene to be implemented. This knowledge is usually obtained from a complete hyperspectral image scene in either a supervised or unsupervised fashion, which prohibits real-time implementation. In this paper, we present a unique constrained spectral unmixing technique, which develops this knowledge in real-time on a pixel-by-pixel basis. Experiments using HYDICE data were conducted to demonstrate this proposed real-time approach for target detection and classification in hyperspectral imagery. Small modifications to the real-time algorithm were made in the experimental section to alleviate practical problems associated with a true pixel-by-pixel implementation.

关键词： Hyperspectral sensors Layout Hyperspectral imaging Object detection computer displays remote monitoring image sensors remote sensing Signal processing image processing

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