Target detection in clutter for sonar imagery

This thesis is concerned with the analysis of side-looking sonar images, and specif- ically with the identification of the types of seabed that are present in such images, and with the detection of man-made objects in such images. Side-looking sonar images are, broadly speaking, the result of the physical interaction between acous- tic waves and the bottom of the sea. Because of this interaction, the types of seabed appear as textured areas in side-looking sonar images. The texture descrip- tors commonly used in the field of sonar imagery fail at accurately identifying the types of seabed because the types of seabed, hence the textures, are extremely variable. In this thesis, we did not use the traditional texture descriptors to identify the types of seabed. We rather used scattering operators which recently appeared in the field of signal and image processing. We assessed how well the types of seabed are identified through two inference algorithms, one based on affine spaces, and the other based on the concept of similarity by composition. This thesis is also concerned with the detection of man-made objects in side-looking sonar im- ages. An object detector may be described as a method which, when applied to a certain number of sonar images, produces a set of detections. Some of these are true positives, and correspond to real objects. Others are false positives, and do not correspond to real objects. The present object detectors suffer from a high false positive rate in complex environments, that is to say, complex types of seabed. The hypothesis we will follow is that it is possible to reduce the number of false positives through a characterisation of the similarity between the detections and the seabed, the false positives being by nature part of the seabed. We will use scattering operators to represent the detections and the same two inference algorithms to quantify how similar the detections are to the seabed

Parameter estimation for stochastic equations with additive fractional Brownian sheet

International audienceWe study the maximum likelihood estimator for stochastic equations with additive fractional Brownian sheet. We use the Girsanov transform for the the two-parameter fractional Brownian motion, as well as the Malliavin calculus and Gaussian regularity theory

Medical image enhancement

Each image acquired from a medical imaging system is often part of a two-dimensional (2-D) image set whose total presents a three-dimensional (3-D) object for diagnosis. Unfortunately, sometimes these images are of poor quality. These distortions cause an inadequate object-of-interest presentation, which can result in inaccurate image analysis. Blurring is considered a serious problem. Therefore, “deblurring” an image to obtain better quality is an important issue in medical image processing. In our research, the image is initially decomposed. Contrast improvement is achieved by modifying the coefficients obtained from the decomposed image. Small coefficient values represent subtle details and are amplified to improve the visibility of the corresponding details. The stronger image density variations make a major contribution to the overall dynamic range, and have large coefficient values. These values can be reduced without much information loss

Fractals in Geoscience and Remote Sensing

Abstract not availableNA-NOT AVAILABL

Earth resources: A continuing bibliography with indexes (issue 62)

This bibliography lists 544 reports, articles, and other documents introduced into the NASA scientific and technical information system between April 1 and June 30, 1989. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Image Registration Workshop Proceedings

Automatic image registration has often been considered as a preliminary step for higher-level processing, such as object recognition or data fusion. But with the unprecedented amounts of data which are being and will continue to be generated by newly developed sensors, the very topic of automatic image registration has become and important research topic. This workshop presents a collection of very high quality work which has been grouped in four main areas: (1) theoretical aspects of image registration; (2) applications to satellite imagery; (3) applications to medical imagery; and (4) image registration for computer vision research

Chaotic Topography in Contemporary French and Francophone Literature

Chaos theory proposed by Ilya Prigogine and Isabelle Stengers illuminates new conclusions about narrative structures in contemporary French and Francophone literature. Espousing an order-out-of-chaos paradigm, my tutor texts by Annie Ernaux, Frankétienne, and Jean-Philippe Toussaint demonstrate how the contemporary notions of identity, gender and genre are innately chaotic but simultaneously offer innovative insights into how these entities are being (re)conceived and (re)presented. Scientific, philosophical, and cultural models of chaos described by Prigogine, Deleuze and Glissant respectively, offer a means to understand the world in order to frame a contemporary cultural topography. Liberated limits of the novel, poetry, and diary genre, viewed through the concept of chaotic "noise", represent richness of information rather than a dearth in order. With Prigogine's Arrow of Time, identity is found in the future not in the past suggesting a non-linear development that is plagued with uncertainty but possibilities. Consequently, identity in contemporary literature is located in others and not in the self challenging traditional notions of this concept. Bifurcation points serve as nodes of "textual instability" revealing themes and trends questioning the function of language, identity and generic transitions in contemporary literature. Through the concept of strange attractors, women, men, language and places within these chaotic tutor texts serve as points of order to which chaotic narratives consistently return advocating the creative force of non-gendered chaos. Accordingly not only can the notion of identity, love and language be viewed as fractal within their own textual space, but the texts themselves transcend generic boundaries. Finally, the contemporary cultural topography is expanding to include electronic literature as an area of critical study. Due to the medium of transmission, i.e., the computer code, electronic literature presents chaotic form and content and challenges traditional notions of `reading' a text. Consequently, the reader interacts with the computer code causing the `narrative' to bifurcate resulting in multiple, unpredictable reading experiences. Chaos theory thus offers a pertinent tool through which to read and interpret this genre. Electronic literature's literariness, viewed through chaos theory, is defined as what changes instead of what remains constant

NASA thesaurus. Volume 3: Definitions

Publication of NASA Thesaurus definitions began with Supplement 1 to the 1985 NASA Thesaurus. The definitions given here represent the complete file of over 3,200 definitions, complimented by nearly 1,000 use references. Definitions of more common or general scientific terms are given a NASA slant if one exists. Certain terms are not defined as a matter of policy: common names, chemical elements, specific models of computers, and nontechnical terms. The NASA Thesaurus predates by a number of years the systematic effort to define terms, therefore not all Thesaurus terms have been defined. Nevertheless, definitions of older terms are continually being added. The following data are provided for each entry: term in uppercase/lowercase form, definition, source, and year the term (not the definition) was added to the NASA Thesaurus. The NASA History Office is the authority for capitalization in satellite and spacecraft names. Definitions with no source given were constructed by lexicographers at the NASA Scientific and Technical Information (STI) Facility who rely on the following sources for their information: experts in the field, literature searches from the NASA STI database, and specialized references

Creating the Future: Research and Technology

With the many different technical talents, Marshall Space Flight Center (MSFC) continues to be an important force behind many scientific breakthroughs. The MSFC's annual report reviews the technology developments, research in space and microgravity sciences, studies in space system concepts, and technology transfer. The technology development programs include development in: (1) space propulsion and fluid management, (2) structures and dynamics, (3) materials and processes and (4) avionics and optics