In this paper we present a new method for adaptively decomposing a multicomponent signal into its components. This method is based on fitting an autoregressive (AR) model to the short-time spectra of the signal. The A...
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ISBN:
(纸本)0819412767
In this paper we present a new method for adaptively decomposing a multicomponent signal into its components. This method is based on fitting an autoregressive (AR) model to the short-time spectra of the signal. The AR parameters represent the coefficients of the linear predictive (LP) polynomial. The roots of this polynomial constitute a set of center frequencies and bandwidths that characterize the modes of the signal. The decomposition process is achieved by applying a time-varying filter bank to the original multicomponent signal. The characteristics of this filter bank are derived from a subset of the roots of the LP polynomial. We have developed a constraining algorithm to determine that subset based on the boundedness of the bandwidths, and the temporal continuity of the center frequencies of the components. We have applied the proposed decomposition method for the separation of the formants of speech signals.
A novel technique for deep level characterization of high-resistivity semiconductor materials, mainly GaAs has been developed. The technique analyzes the current transients generated by photo induced current transient...
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ISBN:
(纸本)0819411000
A novel technique for deep level characterization of high-resistivity semiconductor materials, mainly GaAs has been developed. The technique analyzes the current transients generated by photo induced current transient spectroscopy (PICTS) using a digital data acquisition approach. It is observed that by using the curve fitting technique closely spaced traps within the bandgap could be separately identified and characterized. In addition, the multiple decay time constants obtained from curve fitting consists of sum of exponentials throughout the temperature range centered around a peak obtained from the PICTS spectrum. Each decay time constant (mode) around the specified temperature range represents a trap energy level present in the sample. Since the decay time constants are obtained directly from the transients, trap parameters calculated employing the curve fitting method are more accurate and reliable than those obtained from the two-gated rate window method. The method has been used to characterize high-resistivity materials of interest to optically activated switches and a comparative analysis is reported.
A dynamic model of the wrist articulation is presented in this article. Bones are reconstructed into three dimensional static models from Scanner or IRM computed images.As many computed vision models are possible, the...
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ISBN:
(纸本)0819409448
A dynamic model of the wrist articulation is presented in this article. Bones are reconstructed into three dimensional static models from Scanner or IRM computed images.
As many computed vision models are possible, the demonstration is focused on the consequences on the dynamic model and on the contact detection procedure in particular. An adapted static model is then deduced. Two dynamic models are then presented, one based on mechanics, the other on geometric concepts.
A Fluorescent Image Tracking Velocimetry (FITV) system has been developed to produce two-dimensional velocity maps of flow fields. This system is capable of measurements at flow boundaries, such as the blood-biomateri...
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ISBN:
(纸本)0819411388
A Fluorescent Image Tracking Velocimetry (FITV) system has been developed to produce two-dimensional velocity maps of flow fields. This system is capable of measurements at flow boundaries, such as the blood-biomaterial interfaces in artificial cardiac organs (in-vitro only). Three pulse-coding schemes--a single-pulse code, a dash-dot pulse code, and a constant- frequency pulse code--and associated image analysis algorithms have been developed and tested. These algorithms were applied to analyze flow in three types of artificial cardiac organs: the Novacor Left Ventricular Assist System, the Nimbus AxiPump, and the Hattler Intravenous Membrane Oxygenator. Results are presented and discussed in terms of image recognition. Despite the drawback of time-direction ambiguity, a constant-frequency pulse with a hybrid of constant-frequency and single-pulse analyses was found to provide optimum results for these applications.
In this work, we present a technique which suggests the use of symmetry to reduce the redundancy in images. A symmetry-based image segmentation and coding scheme is described. A segmentation technique is analyzed, and...
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ISBN:
(纸本)0819412236
In this work, we present a technique which suggests the use of symmetry to reduce the redundancy in images. A symmetry-based image segmentation and coding scheme is described. A segmentation technique is analyzed, and applied on natural images, performing their efficient partition. In order to find symmetries in regions of any shape, the concept of axes of symmetry is generalized to skeletons of symmetry, dividing the regions into two symmetric subparts by the introduction of the Medial Axis Transformation of the regions. Each subpart of the regions is then linearly predicted with respect to the skeletons. An efficient coding strategy specifying the shape and the luminance of the regions is described. Results on natural images show that the described technique outperforms the more classical second generation image coding methods in terms of visual quality.
This paper discusses the application of a conceptual clustering algorithm called ITERATE to improve complex problem solving. More specifically, we apply the ITERATE system to build a hierarchy of rule models from sets...
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ISBN:
(纸本)081941199X
This paper discusses the application of a conceptual clustering algorithm called ITERATE to improve complex problem solving. More specifically, we apply the ITERATE system to build a hierarchy of rule models from sets of rules defined for PLAYMAKER, an expert system for characterizing hydrocarbon fields and plays in terms of their essential geological characteristics for the purposes of prospect analysis. PLAYMAKER is built on MIDST, an expert system shell that employs task-specific reasoning structures. The rule model hierarchy derived by ITERATE is then used with the task-specific reasoning structures to develop a more efficient and focused reasoning mechanism. A set of case studies were conducted to demonstrate the improved performance of the reasoning system.
As part of research into document image processing, an algorithm has been developed to detect the degree of skew in a scanned binary image. The principal components of the algorithm are component labelling, a procedur...
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ISBN:
(纸本)0819411973
As part of research into document image processing, an algorithm has been developed to detect the degree of skew in a scanned binary image. The principal components of the algorithm are component labelling, a procedure to reduce the amount of data to be processed, a technique to minimize the effect of non-textual data (graphics, forms, line art, large fonts, and dithered images) on the measurement of skew angle, and the Hough transform. The performance of the algorithm has been evaluated using a sample size of several hundred images of medical journal pages. Evaluation shows that a skew angle may be detected with an accuracy of about 0.50 degree.
The determinations of cloud presence, properties, and radiative influence are high priority requirements for both defense related operations and in the pursuit of research goals for the U.S. Global Change Research Pro...
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ISBN:
(纸本)0819411701
The determinations of cloud presence, properties, and radiative influence are high priority requirements for both defense related operations and in the pursuit of research goals for the U.S. Global Change Research Program. A number of current programs address aspects of the remote sensing of clouds; this paper provides an overview of these programs, their objectives, requirements, and interrelationship. Requirements are divided into three categories: (1) impacts on defense operations and systems, (2) numerical weather prediction (NWP), and (3) climate study objectives, both prognostic and diagnostic. Additionally, current satellite sensor data resources and applicable cloud property retrieval algorithm approaches are described.
A morphology-based algorithm has been developed for point target detection in IRST applications. It exhibits comparable detection and false alarm performance to a median filter. The morphology-based algorithm has an e...
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ISBN:
(纸本)0819411906
A morphology-based algorithm has been developed for point target detection in IRST applications. It exhibits comparable detection and false alarm performance to a median filter. The morphology-based algorithm has an efficient computational paradigm based on combinations of simple nonlinear grayscale operations, which makes it ideally suited to real- time, high data rate IRST applications. A detection filter based on morphological background estimation exhibits spatial high-pass characteristics emphasizing target-like peaks in the data and suppressing all other clutter. Example cases are presented which point out the detection performance differences between the morphological and median approaches. Overall performance results were generated in the form of ROC curves for cloud, horizon and sea clutter IRAMMP backgrounds.
A unique architecture has been developed for a compact programmable optoelectronic logic array. The system is comprised of two arrays of symmetric self electro-optic effect devices (S- SEED) and a 3 dimensional integr...
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ISBN:
(纸本)0819410756
A unique architecture has been developed for a compact programmable optoelectronic logic array. The system is comprised of two arrays of symmetric self electro-optic effect devices (S- SEED) and a 3 dimensional integrated guided-wave crossbar interconnection network. Presently emerging technologies would allow densities of a few hundred thousand S-SEEDs, connected in a wide sense nonblocking manner, per cubic inch. Such arbitrary connectivity, in effect a `virtual 3-D hologram,' would allow execution of complex logic functions.
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