220 Matching Results

Search Results

Advanced search parameters have been applied.

Advanced High-Speed Framing Camera Development for Fast, Visible Imaging Experiments

Description: The advances in high-voltage switching developed in this project allow a camera user to rapidly vary the number of output frames from 1 to 25. A high-voltage, variable-amplitude pulse train shifts the deflection location to the new frame location during the interlude between frames, making multiple frame counts and locations possible. The final deflection circuit deflects to five different frame positions per axis, including the center position, making for a total of 25 frames. To create the preset voltages, electronically adjustable {+-}500 V power supplies were chosen. Digital-to-analog converters provide digital control of the supplies. The power supplies are clamped to {+-}400 V so as not to exceed the voltage ratings of the transistors. A field-programmable gated array (FPGA) receives the trigger signal and calculates the combination of plate voltages for each frame. The interframe time and number of frames are specified by the user, but are limited by the camera electronics. The variable-frame circuit shifts the plate voltages of the first frame to those of the second frame during the user-specified interframe time. Designed around an electrostatic image tube, a framing camera images the light present during each frame (at the photocathode) onto the tube’s phosphor. The phosphor persistence allows the camera to display multiple frames on the phosphor at one time. During this persistence, a CCD camera is triggered and the analog image is collected digitally. The tube functions by converting photons to electrons at the negatively charged photocathode. The electrons move quickly toward the more positive charge of the phosphor. Two sets of deflection plates skew the electron’s path in horizontal and vertical (x axis and y axis, respectively) directions. Hence, each frame’s electrons bombard the phosphor surface at a controlled location defined by the voltages on the deflection plates. To prevent the phosphor from being exposed ...
Date: May 11, 2011
Creator: Amy Lewis, Stuart Baker, Brian Cox, Abel Diaz, David Glass, Matthew Martin
Partner: UNT Libraries Government Documents Department

Determining Camera Gain in Room Temperature Cameras

Description: James R. Janesick provides a method for determining the amplification of a CCD or CMOS camera when only access to the raw images is provided. However, the equation that is provided ignores the contribution of dark current. For CCD or CMOS cameras that are cooled well below room temperature, this is not a problem, however, the technique needs adjustment for use with room temperature cameras. This article describes the adjustment made to the equation, and a test of this method.
Date: December 1, 2010
Creator: Cogliati, Joshua
Partner: UNT Libraries Government Documents Department

Beads on a String: Extended Portraits

Description: When I was first introduced to photography, I was mainly drawn to landscape imagery. I enjoyed being a solitary spectator. Over time, inclusions of figurative elements became more and more apparent in my work. I purposefully began to incorporate a figure into my landscapes, ascribing to it a certain nostalgia and a sense of isolation I was experiencing on many levels at that time. Before long, I felt disconnected from these images because of their ambiguity and generalization. I found myself craving more content and personal commitment in my photography. At the end 2003, I started experimenting with a 4" x 5" format camera, which forced me, to some extent, to change my way of photographing and seeing. That is how the beginning of this new body of work was born. I was accustomed to shooting with a 35 mm camera, which allowed me to be spontaneous, quick and immediate. I permanently switched to a large format. I could see myself benefiting from this change. I lost some of the spontaneity that a 35 mm format offers but I gained the beauty of working with larger negatives and the endless possibilities of view camera movements. Thanks to this technical transformation, I began to develop new ideas. I tried to focus on what truly mattered to me, initially stripped from any necessary relationships among the images. I photographed pieces of time and space, filled with an emotional and psychological charge. More figurative elements kept reappearing and soon dominated my subject matter completely. My motives became utterly wrapped around human values and the differences that distinguish each of us from one another.
Date: December 2004
Creator: Kolčavová, Gabriela
Partner: UNT Libraries

Approximate Quantitative Microscopy of Pulverized Ores, Including the Use of the Camera Lucida

Description: Technical paper issued by the Bureau of Mines over microscopy of pulverized ores. As stated in the introduction, "this paper, which deals with the study of pulverized ores and the use of the camera lucida in such work, discusses an investigation undertaken at the Seattle and the Golden mining experiment stations of the Bureau of Mines" (p. 3). This paper includes tables, illustrations, and photographs.
Date: October 1919
Creator: Coghill, Will H. & Bonardi, J. P.
Partner: UNT Libraries Government Documents Department

The Design and Implementation of an Effective Vision-Based Leader-Follower Tracking Algorithm Using PI Camera

Description: The thesis implements a vision-based leader-follower tracking algorithm on a ground robot system. One camera is the only sensor installed the leader-follower system and is mounted on the follower. One sphere is the only feature installed on the leader. The camera identifies the sphere in the openCV Library and calculates the relative position between the follower and leader using the area and position of the sphere in the camera frame. A P controller for the follower and a P controller for the camera heading are built. The vision-based leader-follower tracking algorithm is verified according to the simulation and implementation.
Date: August 2016
Creator: Li, Songwei
Partner: UNT Libraries

Evaluation of the LLNL Spectrometer for Possible use with the NSTec Optical Streak Camera as a Light Gas Gun Diagnostic

Description: In fiscal year 2012, it was desired to combine a visible spectrometer with a streak camera to form a diagnostic system for recording time-resolved spectra generated in light gas gun experiments. Acquiring a new spectrometer was an option, but it was possible to borrow an existing unit for a period of months, which would be sufficient to evaluate both “off-line” and in-gas gun shots. If it proved adequate for this application, it could be duplicated (with possible modifications); if not, such testing would help determine needed specifications for another model. This report describes the evaluation of the spectrometer (separately and combined with the NSTec LO streak camera) for this purpose. Spectral and temporal resolutions were of primary interest. The first was measured with a monochromatic laser input. The second was ascertained by the combination of the spectrometer’s spatial resolution in the time-dispersive direction and the streak camera’s intrinsic temporal resolution. System responsivity was also important, and this was investigated by measuring the response of the spectrometer/camera system to black body input—the gas gun experiments are expected to be similar to a 3000K black body—as well as measuring the throughput of the spectrometer separately over a range of visible light provided by a monochromator. The flat field (in wavelength) was also measured and the final part of the evaluation was actual fielding on two gas gun shots. No firm specifications for spectral or temporal resolution were defined precisely, but these were desired to be in the 1–2 nm and 1–2 ns ranges, respectively, if possible. As seen below, these values were met or nearly met, depending on wavelength. Other performance parameters were also not given (threshold requirements) but the evaluations performed with laser, black body, and successful gas gun shots taken in aggregate indicate that the spectrometer is adequate for this ...
Date: September 27, 2012
Creator: O'Connor, J., Cradick, J.
Partner: UNT Libraries Government Documents Department

High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term Maintenance: Final Technical Report

Description: The Quest Camera was installed at the Palomar Obervatory in California. The camera was used to carry out a survey of low redshift Type 1a supernovae.The purpose of this DOE grant was to perform short term maintenance on the QUEST camera.
Date: October 16, 2012
Creator: Baltay, Charles
Partner: UNT Libraries Government Documents Department

A compact, discrete CsI(Tl) scintillator/Si photodiode gamma camera for breast cancer imaging

Description: Recent clinical evaluations of scintimammography (radionuclide breast imaging) are promising and suggest that this modality may prove a valuable complement to X-ray mammography and traditional breast cancer detection and diagnosis techniques. Scintimammography, however, typically has difficulty revealing tumors that are less than 1 cm in diameter, are located in the medial part of the breast, or are located in the axillary nodes. These shortcomings may in part be due to the use of large, conventional Anger cameras not optimized for breast imaging. In this thesis I present compact single photon camera technology designed specifically for scintimammography which strives to alleviate some of these limitations by allowing better and closer access to sites of possible breast tumors. Specific applications are outlined. The design is modular, thus a camera of the desired size and geometry can be constructed from an array (or arrays) of individual modules and a parallel hole lead collimator for directional information. Each module consists of: (1) an array of 64 discrete, optically-isolated CsI(Tl) scintillator crystals 3 x 3 x 5 mm{sup 3} in size, (2) an array of 64 low-noise Si PIN photodiodes matched 1-to-1 to the scintillator crystals, (3) an application-specific integrated circuit (ASIC) that amplifies the 64 photodiode signals and selects the signal with the largest amplitude, and (4) connectors and hardware for interfacing the module with a motherboard, thereby allowing straightforward computer control of all individual modules within a camera.
Date: Autumn 2000
Creator: Gruber, Gregory J.
Partner: UNT Libraries Government Documents Department

A CCD Camera with Electron Decelerator for Intermediate Voltage Electron Microscopy

Description: Electron microscopists are increasingly turning to Intermediate Voltage Electron Microscopes (IVEMs) operating at 300 - 400 kV for a wide range of studies. They are also increasingly taking advantage of slow-scan charge coupled device (CCD) cameras, which have become widely used on electron microscopes. Under some conditions CCDs provide an improvement in data quality over photographic film, as well as the many advantages of direct digital readout. However, CCD performance is seriously degraded on IVEMs compared to the more conventional 100 kV microscopes. In order to increase the efficiency and quality of data recording on IVEMs, we have developed a CCD camera system in which the electrons are decelerated to below 100 kV before impacting the camera, resulting in greatly improved performance in both signal quality and resolution compared to other CCDs used in electron microscopy. These improvements will allow high-quality image and diffraction data to be collected directly with the CCD, enabling improvements in data collection for applications including high-resolution electron crystallography, single-particle reconstruction of protein structures, tomographic studies of cell ultrastructure and remote microscope operation. This approach will enable us to use even larger format CCD chips that are being developed with smaller pixels.
Date: March 17, 2008
Creator: Downing, Kenneth H; Downing, Kenneth H. & Mooney, Paul E.
Partner: UNT Libraries Government Documents Department

X-ray streak camera temporal resolution improvement using a longitudinal time-dependent field

Description: X-ray streak cameras (XSC) have been known to be one of the fastest detectors forultrafast X-ray science. A number of applications in material science, biochemistry, accelerator physics, require sub-picosecond resolution to study new phenomena. Inthis paper, we report on a new method which can potentially improve the temporal resolution of a streak camera down to 100 femtoseconds. This method uses a time-dependent acceleration field to lengthen the photoelectron bunch, significantlyimproving the time resolution as well as reducing the time dispersion caused byinitial energy spread and the effects fromthe space charge forces. A computer simulation of an XSC using this method shows significant improvement in the resolution.
Date: May 9, 2008
Creator: Qiang, Ji; Qiang, J.; Byrd, J.M.; Feng, J. & Huang, G.
Partner: UNT Libraries Government Documents Department

Progress on Modeling of Ultrafast X-Ray Streak Cameras

Description: Streak cameras continue to be useful tools for studying phenomena on the picoseconds time scale. We have employed accelerator modeling tools to understand and possibly improve the time resolution of present and future streak cameras. This effort has resulted in an end-to-end model of the camera. This model has contributed to the recent measurement of 230 fsec (FWHM) resolution measured at 266 nm in the Advanced Light Source Streak Camera Laboratory. We describe results from this model that show agreement with the experiments. We also extrapolate the performance of this camera including several possible improvements.
Date: June 22, 2007
Creator: Huang, G.; Byrd, J.M.; Feng, J.; Qiang, J. & Wang, W.
Partner: UNT Libraries Government Documents Department

Preliminary Design of Pinhole camera for NSLS-II Project.

Description: The NSLS-II Light Source being built at Brookhaven National Laboratory is expected to provide very small emittances and electron beam sizes. High resolution imaging systems are required in order to provide robust measurements. The pinhole camera will utilize 6-fold magnification with a pinhole placed inside a crotch absorber. The pinhole is protected from high power synchrotron radiation with a filter made of refractory metal. In this paper we provide resolution analyses, heat load calculations, and optimization details for the NSLS-II pinhole camera, including beamline design.
Date: May 4, 2009
Creator: Pinayev,I.; Kosciuk, B. & Singh, O.
Partner: UNT Libraries Government Documents Department

Quantification of Human Thermal Comfort for Residential Building's Energy Saving

Description: Providing conditioned and fully controlled room is the final goal for having a comfortable building. But on the other hand making smart controllers to provide the required cooling or heating load depending on occupants' real time feeling is necessary. This study has emphasized on finding a meaningful and steady state parameter in human body that can be interpreted as comfort criterion which can be expressed as the general occupants' sensation through their ambient temperature. There are lots of researches on human physiological behavior in different situations and also different body parts reaction to the same ambient situation. Body parts which have the biggest reliable linear fluctuation to the changes are the best subject for this research. For these tests, wrist and palm have been selected and their temperatures on different people have been measured accurately with thermal camera to follow the temperature trend on various comfort levels. It is found that each person reaches to his own unique temperature on these two spots, when he/ she feels comfortable, or in other word each person's body temperature is a precise nominate for comfort feeling of that individual. So in future by having this unique comfort parameter and applying them to the HVAC system temperature control, controlling the dynamic temperature and correlating the indoor condition depending on the occupants instant thermal comfort level, would be a rational choice to bring convenience while energy has been saved more.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: August 2016
Creator: Sharifani, Pooya
Partner: UNT Libraries

An Evaluation of Student Learning and Engagement in a Technology-Enhanced Algebra Unit on Slope

Description: The purpose of this study was to examine the effectiveness of a technology-enhanced unit on slope in algebra. The technology used in the study was the Topological Panorama Camera (Topocam). The research questions explored the learning and transfer of knowledge about slope and the engagement level of students during Topocam learning activities. The Topocam is a computer-controlled camera that moves on a modular track while it scans a scene through a vertical slit. Students can program the speed of the camera and frequency of pictures. They then witness the results of time and motion in the image created by the camera. Data for this study were collected from a pretest/posttest, as well as from observations of indicators of engaged learning. The research population consisted of 46 students from three classes of Algebra I students. Three classroom teachers each taught a unit on slope, while a fourth teacher conducted the activities with the Topocam for all the classes. The classroom activities focused on the concept of slope as a rate of change utilizing coordinate grids. The Topocam activities involved students in collaboratively making and testing predictions about slope. The findings of the study indicate that student learning did occur with this technology-enhanced unit on slope in algebra. Students showed statistically significant improvement in understanding slope and in transferring that concept to other situations. Since technology was only part of the unit presentation, the amount of learning attributed to the Topocam activities cannot be determined. However, students demonstrated a high degree of engagement in learning while working with the Topocam which suggests that the activities were a factor. A low correlation between students’ slope unit test scores and previous algebra performance may indicate that students who have not been successful in algebra were more successful in the technology-enhanced unit. Some variation was ...
Date: August 2000
Creator: Beck, Elaine K.
Partner: UNT Libraries

Ran, Shulamit: Concerto da Camera II, Analysis of Pitch and Formal Structure

Description: The thesis speculates upon the three movements of Concerto da Camera II (1987), scored for Bb clarinet, string quartet and piano) in these four aspects: 1) the formal structure, 2) the manipulation of the notes of whole-tone, octatonic, and chromatic scales in octave displacement, 3) the potential combination of subsets that present different levels of pitch transformation in melodic and harmonic structure, and 4) the usage of intervals of minor seconds, tritones, and perfect fourths or fifths which dominates the linear writing. All of these features demonstrate that the music has strong structural elements in form, motives, and sonorities, which unify the piece in an aurally coherent style as an organic whole. This study should provide more insight into the understanding of Ran's unique compositional technique and style.
Date: May 2000
Creator: Lin, Sheng
Partner: UNT Libraries

[Joe and Bernice Clark]

Description: Photograph of Joe and Bernice Clark sitting on a couch looking at a camera. In the image, Bernice is smiling looking down at a new camera with Clark's arm around her. A Christmas tree and presents can be seen to the left of the frame indicated that the camera was a present.
Date: unknown
Creator: Clark, Joe
Partner: UNT Libraries Special Collections

Extemporizing Reawakened: Saxophonist Branford Marsalis's Approach to the Cadenza for Concertino da Camera for Alto Saxophone and Eleven Instruments by Jacques Ibert

Description: Whether provided by a composer, written out by a performer or completely improvised, the cadenza became a vehicle for performers' creativity, lyricism and technical prowess in the eighteenth and nineteenth centuries. The debate about whether to notate or improvise cadenzas, a question as old as the cadenza itself, continues today. Saxophonists have not been involved in this debate, since the instrument is a product of the mid-nineteenth century and was in its infancy just as the practice of improvising cadenzas was fading. This study documents an unprecedented, recently-recorded, improvised cadenza in one of the most significant twentieth-century saxophone works: Jacques Ibert's Concertino da Camera for Alto Saxophone and Eleven Instruments (1935). Saxophonist Branford Marsalis's neo-cadenza for Ibert's composition presents an aggregate of the twenty-first-century performer improvising a cadenza to a twentieth-century work, in a tradition that was common centuries ago. The document begins with an inquiry into improvised cadenzas, and proceeds to an examination of the performance history of the cadenza for the Concertino da Camera. Twenty professionally-recorded versions of the cadenza are presented in order to understand the performance history of the cadenza, and to place the Marsalis cadenza into context. This research culminates in a transcription and analysis of the cadenza as improvised and recorded by Marsalis. Remarks from a personal interview with Marsalis are also included.
Access: This item is restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2006
Creator: James, Matthew T.
Partner: UNT Libraries

Development and Performance of Bechtel Nevada's Nine-Frame Camera System

Description: Bechtel Nevada, Los Alamos Operations, has developed a high-speed, nine-frame camera system that records a sequence from a changing or dynamic scene. The system incorporates an electrostatic image tube with custom gating and deflection electrodes. The framing tube is shuttered with high-speed gating electronics, yielding frame rates of up to 5MHz. Dynamic scenes are lens-coupled to the camera, which contains a single photocathode gated on and off to control each exposure time. Deflection plates and drive electronics move the frames to different locations on the framing tube output. A single charge-coupled device (CCD) camera then records the phosphor image of all nine frames. This paper discusses setup techniques to optimize system performance. It examines two alternate philosophies for system configuration and respective performance results. We also present performance metrics for system evaluation, experimental results, and applications to four-frame cameras.
Date: July 1, 2002
Creator: Baker, S. A.; Griffith, M. J. & Tybo, J. L.
Partner: UNT Libraries Government Documents Department

Evaluating intensified camera systems

Description: This paper describes image evaluation techniques used to standardize camera system characterizations. Key areas of performance include resolution, noise, and sensitivity. This team has developed a set of analysis tools, in the form of image processing software used to evaluate camera calibration data, to aid an experimenter in measuring a set of camera performance metrics. These performance metrics identify capabilities and limitations of the camera system, while establishing a means for comparing camera systems. Analysis software is used to evaluate digital camera images recorded with charge-coupled device (CCD) cameras. Several types of intensified camera systems are used in the high-speed imaging field. Electro-optical components are used to provide precise shuttering or optical gain for a camera system. These components including microchannel plate or proximity focused diode image intensifiers, electro-static image tubes, or electron-bombarded CCDs affect system performance. It is important to quantify camera system performance in order to qualify a system as meeting experimental requirements. The camera evaluation tool is designed to provide side-by-side camera comparison and system modeling information.
Date: July 1, 2000
Creator: Baker, S. A.
Partner: UNT Libraries Government Documents Department

[Letter from Camilla Wallace to Charles Moore, October 19, 1896]

Description: Letter from Camilla Wallace to Charles B. Moore in which she relates the health of her family; a trip up a mountain and its impact on the health of Tom; Will has a new camera; and her plans to join the camera club. Will is the secretary of the irrigation company. She is helping with the office work, which she enjoys. She plans to vote for William Jennings Bryan in the hopes of changing policies.
Date: October 19, 1896
Creator: Wallace, Camilla
Partner: UNT Libraries Special Collections

Reliable and Repeatable Characterization of Optical Streak Cameras

Description: Optical streak cameras are used as primary diagnostics for a wide range of physics and laser performance verification experiments at the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electronic components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases the characterization data is used to “correct” data images, to remove some of the nonlinearities. In order to obtain these camera characterizations, a specific data set is collected where the response to specific known inputs is recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, temporal resolution, etc., from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information.
Date: March 1, 2008
Creator: Michael R. Charest, Peter Torres III, Christopher Silbernagel
Partner: UNT Libraries Government Documents Department

Microprocessor-controlled, wide-range streak camera

Description: Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera’s user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.
Date: September 1, 2006
Creator: Amy E. Lewis, Craig Hollabaugh
Partner: UNT Libraries Government Documents Department