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Image Content Engine (ICE)

Description: The Image Content Engine (ICE) is being developed to provide cueing assistance to human image analysts faced with increasingly large and intractable amounts of image data. The ICE architecture includes user configurable feature extraction pipelines which produce intermediate feature vector and match surface files which can then be accessed by interactive relational queries. Application of the feature extraction algorithms to large collections of images may be extremely time consuming and is launched as a batch job on a Linux cluster. The query interface accesses only the intermediate files and returns candidate hits nearly instantaneously. Queries may be posed for individual objects or collections. The query interface prompts the user for feedback, and applies relevance feedback algorithms to revise the feature vector weighting and focus on relevant search results. Examples of feature extraction and both model-based and search-by-example queries are presented.
Date: March 26, 2007
Creator: Brase, J M
Partner: UNT Libraries Government Documents Department

A qualitative study of internal wave ship wakes: Dependence on environmental conditions and experimental parameters

Description: For the past several years the UK-US Radar Ocean Imaging Program has conducted a series of field experiments with the primary purpose of gathering real aperture radar (RAR) imagery at low grazing angle of ship-generated internal wave (IW) wakes. The first observations with RAR`s were made in the 1989 Loch Linnhe experiment where it was observed that radar images at low grazing angles (LGA) of approximately six degrees had significantly higher modulation levels than SAR images made at higher grazing angles of 35 - 65 degrees. These initial observations have led to several more experiments designed to verify the phenomenon and to test its dependence on experimental and environmental conditions. A parallel effort began to develop theoretical models of the LGA imaging process. Through this series of experiments we have developed an extensive database of radar imagery and supporting environmental data. The objective of this report is twofold: (1) To describe the database and the associated space of parameters. We will look at the coverage of the parameter space within the database and at areas which should be covered. (2) To take an initial look at the dependence of qualitative modulation strength on the experimental and environmental parameters. This first look will indicate the strongest dependencies which can then be studied in more detail. Section 2 describes the experimental database and Section 3 discusses the parameter space, image quality, and their relationships based on the images in the database. In Section 4 we summarize our conclusions and make recommendations for both future analyses and experiments.
Date: April 24, 1995
Creator: Mullenhoff, C.J. & Brase, J.M.
Partner: UNT Libraries Government Documents Department

Micro-tomography using synchrotron radiation

Description: This paper discusses the results of recent experiments at Stanford Synchrotron Radiation Laboratory (SSRL) and Hamburger Synchrotronstrahlungslabor (HASYLAB) which were designed to explore the feasibility of using synchrotron radiation in high-resolution, computerized, critical-absorption tomography. The results demonstrate that it is possible, using absorption-edge differencing, to identify adjacent elements in the periodic table with high sensitivity. Furthermore, by using the fine structure in the absorption spectra, it is possible to distinguish between regions of different chemical states. Methods of using synchrotron radiation for high-resolution, three-dimensional chemical-state mapping in small samples are discussed.
Date: April 9, 1986
Creator: Johnson, Q.C.; Kinney, J.H.; Bonse, U.; Nichols, M.C.; Nusshardt, R. & Brase, J.M.
Partner: UNT Libraries Government Documents Department

High-resolution CT system for elemental mapping

Description: The performance of a low-temperature CCD camera for application in computed tomography (CT) was tested on beamline II-3 at the Stanford Synchrotron Radiation Laboratory (SSRL). In the present system, transmitted x-rays are converted to visible light on a phosphor-coated optical face plate. This light illuminates a thermoelectrically cooled CCD, which is operated as a charge counting device. By modulating the energy of the x-ray beam, we can obtain elemental and chemical-state information about the reconstructed voxels. Presently, the resolution is about 50 microns, and is to a large extent controlled by the quality of the phosphor. The spatial resolution and chemical sensitivity of the system are reported. Applications to materials and biological sciences are discussed.
Date: August 1, 1986
Creator: Kinney, J.H.; Johnson, Q.C.; Brase, J.M.; Nichols, M.C.; Nusshardt, R. & Bonse, U.
Partner: UNT Libraries Government Documents Department

Wavefront control system for the Keck telescope

Description: The laser guide star adaptive optics system currently being developed for the Keck 2 telescope consists of several major subsystems: the optical bench, wavefront control, user interface and supervisory control, and the laser system. The paper describes the design and implementation of the wavefront control subsystem that controls a 349 actuator deformable mirror for high order correction and tip-tilt mirrors for stabilizing the image and laser positions.
Date: March 1, 1998
Creator: Brase, J. M., LLNL
Partner: UNT Libraries Government Documents Department

Keck adaptive optics: control subsystem

Description: Adaptive optics on the Keck 10 meter telescope will provide an unprecedented level of capability in high resolution ground based astronomical imaging. The system is designed to provide near diffraction limited imaging performance with Strehl {gt} 0.3 n median Keck seeing of r0 = 25 cm, T =10 msec at 500 nm wavelength. The system will be equipped with a 20 watt sodium laser guide star to provide nearly full sky coverage. The wavefront control subsystem is responsible for wavefront sensing and the control of the tip-tilt and deformable mirrors which actively correct atmospheric turbulence. The spatial sampling interval for the wavefront sensor and deformable mirror is de=0.56 m which gives us 349 actuators and 244 subapertures. This paper summarizes the wavefront control system and discusses particular issues in designing a wavefront controller for the Keck telescope.
Date: March 8, 1996
Creator: Brase, J.M.; An, J. & Avicola, K.
Partner: UNT Libraries Government Documents Department

Nonlinear image filtering within IDP++

Description: IDP++, image and data processing in C++, is a set of a signal processing libraries written in C++. It is a multi-dimension (up to four dimensions), multi-data type (implemented through templates) signal processing extension to C++. IDP++ takes advantage of the object-oriented compiler technology to provide ``information hiding.`` Users need only know C, not C++. Signals or data sets are treated like any other variable with a defined set of operators and functions. We here some examples of the nonlinear filter library within IDP++. Specifically, the results of MIN, MAX median, {alpha}-trimmed mean, and edge-trimmed mean filters as applied to a real aperture radar (RR) and synthetic aperture radar (SAR) data set.
Date: February 9, 1995
Creator: Lehman, S.K.; Wieting, M.G. & Brase, J.M.
Partner: UNT Libraries Government Documents Department

Adaptive optics at Lick Observatory: System architecture and operations

Description: We will describe an adaptive optics system developed for the 1 meter Nickel and 3 meter Shane telescopes at Lick Observatory. Observing wavelengths will be in the visible for the 1 meter telescope and in the near IR on the 3 meter. The adaptive optics system design is based on a 69 actuator continuous surface deformable mirror and a Hartmann wavefront sensor equipped with an intensified CCD framing camera. The system has been tested at the Cassegrain focus of the 1 meter telescope where the subaperture size is 12.5 cm. The wavefront control calculations are performed on a four processor single board computer controlled by a Unix-based system. We will describe the optical system and give details of the wavefront control system design. We will present predictions of the system performance and initial test results.
Date: March 1, 1994
Creator: Brase, J. M.; An, J. & Avicola, K.
Partner: UNT Libraries Government Documents Department

An adaptive optics package designed for astronomical use with a laser guide star tuned to an absorption line of atomic sodium

Description: We present the design and implementation of a very compact adaptive optic system that senses the return light from a sodium guide-star and controls a deformable mirror and a pointing mirror to compensate atmospheric perturbations in the wavefront. The deformable mirror has 19 electrostrictive actuators and triangular subapertures. The wavefront sensor is a Hartmann sensor with lenslets on triangular centers. The high-bandwidth steering mirror assembly incorporates an analog controller that samples the tilt with an avalanche photodiode quad cell. An {line_integral}/25 imaging leg focuses the light into a science camera that can either obtain long-exposure images or speckle data. In laboratory tests overall Strehl ratios were improved by a factor of 3 when a mylar sheet was used as an aberrator. The crossover frequency at unity gain is 30 Hz.
Date: April 11, 1994
Creator: Salmon, J. T.; Avicola, K. & Brase, J. M.
Partner: UNT Libraries Government Documents Department

Tip-tilt compensation: Resolution limits for ground-based telescopes using laser guide star adaptive optics. Revision 2

Description: The angular resolution of long-exposure images from ground-based telescopes equipped with laser guide star adaptive optics systems is fundamentally limited by the the accuracy with which the tip-tilt aberrations introduced by the atmosphere can be corrected. Assuming that a natural star is used as the tilt reference, the residual error due to tilt anisoplanatism can significantly degrade the long-exposure resolution even if the tilt reference star is separated from the object being imaged by a small angle. Given the observed distribution of stars in the sky, the need to find a tilt reference star quite close to the object restricts the fraction of the sky over which long-exposure images with diffraction limited resolution can be obtained. In this paper, the authors present a comprehensive performance analysis of tip-tilt compensation systems that use a natural star as a tilt reference, taking into account properties of the atmosphere and of the Galactic stellar populations, and optimizing over the system operating parameters to determine the fundamental limits to the long-exposure resolution. Their results show that for a ten meter telescope on Mauna Kea, if the image of the tilt reference star is uncorrected, about half the sky can be imaged in the V band with long-exposure resolution less than 60 milli-arc-seconds (mas), while if the image of the tilt reference star is fully corrected, about half the sky can be imaged in the V band with long-exposure resolution less than 16 mas. Furthermore, V band images long-exposure resolution of less than 16 mas may be obtained with a ten meter telescope on Mauna Kea for unresolved objects brighter than magnitude 22 that are fully corrected by a laser guide star adaptive optics system. This level of resolution represents about 70% of the diffraction limit of a ten meter telescope in the V band ...
Date: October 8, 1992
Creator: Olivier, S. S.; Max, C. E.; Gavel, D. T. & Brase, J. M.
Partner: UNT Libraries Government Documents Department

Image Content Engine (ICE): A System for Fast Image Database Searches

Description: The Image Content Engine (ICE) is being developed to provide cueing assistance to human image analysts faced with increasingly large and intractable amounts of image data. The ICE architecture includes user configurable feature extraction pipelines which produce intermediate feature vector and match surface files which can then be accessed by interactive relational queries. Application of the feature extraction algorithms to large collections of images may be extremely time consuming and is launched as a batch job on a Linux cluster. The query interface accesses only the intermediate files and returns candidate hits nearly instantaneously. Queries may be posed for individual objects or collections. The query interface prompts the user for feedback, and applies relevance feedback algorithms to revise the feature vector weighting and focus on relevant search results. Examples of feature extraction and both model-based and search-by-example queries are presented.
Date: March 22, 2005
Creator: Brase, J M; Paglieroni, D W; Weinert, G F; Grant, C W; Lopez, A S & Nikolaev, S
Partner: UNT Libraries Government Documents Department

Phase retrieval for adaptive optics system calibration

Description: Our objective in this report is to develop methods to determine the output pupil wavefront using intensity measurements directly from the science detector. This wavefront can then be used to determine a reference wavefront which will precorrect for the non-common-path aberrations and produce the desired wavefront at the science detector. We describe two phase retrieval algorithms that can be used and a set of simulation studies of AO system calibration. We present the initial experimental results of applying this technique in calibration of the Lick Observatory laser guidestar AO system in a later paper.
Date: August 1, 1997
Creator: Brase, J.M.; Carrano, C.J.; Macintosh, B.A.; Olivier, S.S. & An, J.R.
Partner: UNT Libraries Government Documents Department

Progress reports for period November 1--30, 1994 -- Joint UK/US Radar Program

Description: This report gives the principle investigator, objectives, recent accomplishments, milestones for reporting period, expected milestones for ensuing period, other issues and planned expenditures for the following programs: airborne RAR/SAR; radar data processor; ground-based SAR signal processing workstation; static airborne radar; multi-aperture space-time array radar; radar field experiments; data analysis and detection theory; management; E-2C radar data analysis;modeling and analysis; current meter array; UCSB wave tank; stratified flow facility; and IR sensor system. Budget status is also given.
Date: December 19, 1994
Creator: Twogood, R.E.; Brase, J.M.; Mantrom, D.D.; Chambers, D.H. & Robey, H.F.
Partner: UNT Libraries Government Documents Department

Progress reports for October 1994 -- Joint UK/US Radar Program

Description: This report gives the principle investigator, objectives, recent accomplishments, milestones for reporting period, expected milestones for ensuing period, other issues and planned expenditures for each of the following programs: airborne RAR/SAR; radar data processor; ground-based SAR signal processing workstation; static airborne radar; multi-aperture space-time array radar; radar field experiments; data analysis and detection theory; management; E-2C radar data analysis; modeling and analysis; current meter array; UCSB wave tank; stratified flow facility; and IR sensor system. Finally the budget status is given.
Date: November 18, 1994
Creator: Twogood, R.E.; Brase, J.M.; Mantrom, D.D.; Chambers, D.H. & Robey, H.F.
Partner: UNT Libraries Government Documents Department

Technical challenges for the future of high energy lasers

Description: The Solid-State, Heat-Capacity Laser (SSHCL) program at Lawrence Livermore National Laboratory is a multi-generation laser development effort scalable to the megawatt power levels with current performance approaching 100 kilowatts. This program is one of many designed to harness the power of lasers for use as directed energy weapons. There are many hurdles common to all of these programs that must be overcome to make the technology viable. There will be a in-depth discussion of the general issues facing state-of-the-art high energy lasers and paths to their resolution. Despite the relative simplicity of the SSHCL design, many challenges have been uncovered in the implementation of this particular system. An overview of these and their resolution are discussed. The overall system design of the SSHCL, technological strengths and weaknesses, and most recent experimental results will be presented.
Date: January 10, 2007
Creator: LaFortune, K N; Hurd, R L; Fochs, S N; Rotter, M D; Pax, P H; Combs, R L et al.
Partner: UNT Libraries Government Documents Department

X-ray imaging: Status and trends

Description: There is a veritable renaissance occurring in x-ray imaging. X-ray imaging by radiography has been a highly developed technology in medicine and industry for many years. However, high resolution imaging has not generally been practical because sources have been relatively dim and diffuse, optical elements have been nonexistent for most applications, and detectors have been slow and of low resolution. Materials analysis needs have therefore gone unmet. Rapid progress is now taking place because we are able to exploit developments in microelectronics and related material fabrication techniques, and because of the availability of intense x-ray sources. This report describes the methods and uses of x-ray imaging along with a discussion of technology advances in these areas.
Date: August 1, 1987
Creator: Ryon, R.W.; Martz, H.E.; Hernandez, J.M.; Haskins, J.J.; Day, R.A.; Brase, J.M. et al.
Partner: UNT Libraries Government Documents Department

ASAP progress and expenditure report for the month of December 1--31, 1995. Joint UK/US radar program

Description: The RAR/SAR is a high-priority radar system for the joint US/UK Program. Based on previous experiment results and coordination with the UK, specifications needed for future radar experiments were identified as follows: dual polarimetric (HH and VV) with medium to high resolution in SAR mode. Secondary airborne installation requirements included; high power (circa 10kw) and SLIER capability to emulate Tupelev-134 type system; initially x-band but easily extendible to other frequencies. In FY96 we intended to enhance the radar system`s capabilities by providing a second polarization (VV), spotlight imaging mode, extended frequency of operation to include S- band, increase power, and interface to an existing infrared sensor. Short term objectives are: continue to evaluate and characterize the radar system; upgrade navigation and real-time processing capability to refine motion compensation; upgrade to dual polarimetry (add VV); and develop a ``spotlight`` mode capability. Accomplishments this reporting period: design specifications for the SAR system polarimetric upgrade are complete. The upgrade is ready to begin the procurement cycle when funds become available. System characterization is one of the highest priority tasks for the SAR. Although the radar is dedicated for our use, Hughes is waiting for contract funding before allowing us access to the hardware
Date: January 19, 1996
Creator: Twogood, R.E.; Brase, J.M.; Chambers, D.H.; Mantrom, D.D.; Miller, M.G.; Newman, M.J. et al.
Partner: UNT Libraries Government Documents Department

ASAP progress and expenditure report for the month of February 1--29, 1996

Description: This is the ASAP progress and expenditure report for the month of February, 1996. The individual projects` report includes the sponsoring organization, the project identification, the principal investigator, long term objectives, short term objectives, accomplishments this reporting period, identification of issues or concerns, project budget estimate for the fiscal year, and monthly actual and year to date expenditures. The research project concerns a joint US/UK program to develop a high-priority radar system based on real aperture and synthetic aperature radar. Topics being researched include airborne RAR/SAR; radar data processor; ground-based SAR signal processing workstation; static airborne radar; radar field experiments; data analysis and detection theory; program management; modeling and analysis; UCSB wave tank; stratified wave tank; and experiments in a thermo-stratified tank at the Institute of Applied Physics, Russia.
Date: March 20, 1996
Creator: Twogood, R.E.; Brase, J.M.; Chambers, D.H.; Mantrom, D.M.; Miller, M.G.; Newman, M.J. et al.
Partner: UNT Libraries Government Documents Department

Direct imaging of extra-solar planets

Description: Direct imaging of extra-solar planets may be possible with the new generation of large ground-based telescopes equipped with state- of- the-art adaptive optics (AO) systems to compensate for the blurring effect of the Earth`s atmosphere. The first of these systems is scheduled to begin operation in 1998 on the 10 in Keck II telescope. In this paper, general formulas for high-contrast imaging with AO systems are presented and used to calculate the sensitivity of the Keck AO system. The results of these calculations show that the Keck AO system should achieve the sensitivity necessary to detect giant planets around several nearby bright stars.
Date: March 1, 1997
Creator: Olivier, S.S.; Max, V.E.; Brase, J.M.; Caffano, C.J.; Gavel, D.T. & Macintosh, B.A.
Partner: UNT Libraries Government Documents Department

Preliminary results of the LLNL airborne experimental test-bed SAR system

Description: The Imaging and Detection Program (IDP) within Laser Programs at Lawrence Livermore National Laboratory (LLNL) in cooperation with the Hughes Aircraft Company has developed a versatile, high performance, airborne experimental test-bed (AETB) capability. The test-bed has been developed for a wide range of research and development experimental applications including radar and radiometry plus, with additional aircraft modifications, optical systems. The airborne test-bed capability has been developed within a Douglas EA-3B Skywarrior jet aircraft provided and flown by Hughes Aircraft Company. The current test-bed payload consists of an X-band radar system, a high-speed data acquisition, and a real-time processing capability. The medium power radar system is configured to operate in a high resolution, synthetic aperture radar (SAR) mode and is highly configurable in terms of waveforrns, PRF, bandwidth, etc. Antennas are mounted on a 2-axis gimbal in the belly radome of the aircraft which provides pointing and stabilization. Aircraft position and antenna attitude are derived from a dedicated navigational system and provided to the real-time SAR image processor for instant image reconstruction and analysis. This paper presents a further description of the test-bed and payload subsystems plus preliminary results of SAR imagery.
Date: January 16, 1996
Creator: Miller, M.G.; Mullenhoff, C.J.; Kiefer, R.D.; Brase, J.M.; Wieting, M.G.; Berry, G.L. et al.
Partner: UNT Libraries Government Documents Department