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Passive Synthetic Aperture Array Imaging At Millimeter Wave Frequencies Using Novel Electro Optical Detection And Processing
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Book Synopsis Passive Synthetic Aperture Array Imaging at Millimeter Wave Frequencies Using Novel Electro-optical Detection and Processing by :
Download or read book Passive Synthetic Aperture Array Imaging at Millimeter Wave Frequencies Using Novel Electro-optical Detection and Processing written by and published by . This book was released on 2006 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this effort we have designed, fabricated, and demonstrated a one-dimensional synthetic aperture imaging system for the passive imaging of millimeter waves (MMWs) using optical upconversion and correlation techniques. The advantage of this approach over alternate techniques is that the proposed system does not require expensive high-speed electronic detection and read out circuits and it is light enough to be used on UAV platforms. This technique eliminates the need for a lens and can provide high resolution at mm wavelengths by extending the baseline of the antenna array. We developed a novel optical feedback technique that allows us to lock the phase of each optical carrier with a coherent reference beam. We have demonstrated the feasibility of the technology by building a linear, four element sparse aperture antenna array capable of imaging at mm wavelengths using commercial, off-the-shelf telecommunications components. The system was used to image a 35 0Hz plane wave and demonstrated near diffraction limited resolution.
Book Synopsis Passive Synthetic Aperture Array Imaging at Millimeter Wave Frequencies by :
Download or read book Passive Synthetic Aperture Array Imaging at Millimeter Wave Frequencies written by and published by . This book was released on 2005 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this effort we investigated the design of synthetic aperture imaging systems for passive imaging of millimeter waves (MMWs) using a novel nano-photonic detector array. The idea is to demonstrate a lightweight and low power MMW imaging system with the highest possible resolution. To increase resolution we investigated the use of a "lensless" interferometric imaging system that is created by placing a sparse array of electro-optical MMW detectors along the fuselage of a UAV, or other airborne platforms. The results included the development of high frequency, W-band, electro-optical modulators with sensitivities that rival MMIC based approaches. Unlike the MMIC approaches, the electro-optical detectors do not require expensive low noise amplifiers and can be constructed monolithically. We also conducted an analytical and numerical study on the use of coherent optical beam forming as a practical approach towards the design of a "sparse array" imaging system. Further work will be devoted towards an experimental proof-of-concept demonstration of the coherent optical beam forming approach coupled with the electro-optical MMW detectors.
Book Synopsis High-speed Millimeter-wave Active Incoherent Fourier Domain Imaging by : Stavros Vakalis
Download or read book High-speed Millimeter-wave Active Incoherent Fourier Domain Imaging written by Stavros Vakalis and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Millimeter-wave imaging is used in applications such as security screening, remote sensing, medical imaging, and non-destructive testing due to the good penetration characteristics of millimeter-wave radiation which can provide "see-through" capabilities. Electromagnetic signals in the frequency range of 30-300 GHz can penetrate easily through materials like clothing, fog, and smoke, and at the same time provide image reconstruction with fine spatial resolution. Millimeter-wave imaging is typically implemented by means of mechanical or electrical scanning which requires long data acquisition times or a large number of active components. Computational imaging can reduce both the data acquisition time and the number of active components, but this comes at the cost of heavy computational loads, which makes real-time operation challenging. Passive millimeter-wave imaging systems that capture thermal signals and operate similarly to optical cameras, are very costly because they need to employ highly sensitive receivers due to thermal radiation being extremely low power at millimeter-wave frequencies. A paradigm shift is needed in order to advance the current imaging modalities in millimeter-wave frequencies.In this dissertation, I present a newly developed millimeter-wave imaging technique called active incoherent millimeter-wave (AIM) imaging which combines the benefits of active and passive millimeter-wave imaging. This approach combines the high signal-to-noise ratio capabilities of active millimeter-wave imaging systems with the fast image formation potential of passive millimeter-wave imaging systems. The combination is achieved by illuminating the scene with multiple spatially distributed noise transmitters that mimic the randomness of thermal radiation. Because the concept of incoherent noise illumination has not been investigated thoroughly in the literature of millimeter-wave imaging, I discuss design considerations for creating a space-time incoherent transmitter and novel measurements for characterizing space-time incoherence. Starting from my earlier work in microwave frequencies, I present the system design and calibration approach, along with an experimental demonstration of a millimeter-wave active incoherent digital array. The array is capable of generating millimeter-wave video at very high frame rates, and millimeter-wave imaging results of 652 frames per second of a sphere moving in a pendulum motion are included. The scenario of using the stray reflections from a small set of communications transmitters is also examined and I present results using WiFi and fifth-generation (5G) communications signals. I also expand interferometric imaging to three dimensions using a novel pulse modulation as an envelope on the noise signals to provide differentiation along the range dimension. Prior to this work, three-dimensional interferometric millimeter-wave imaging had only been implemented in the near-field region or using three-dimensional volumetric arrays, which pose significant size and volume concerns. A new algorithm for three-dimensional interferometric image formation is presented along with simulated results and experimental measurements.
Book Synopsis Laser Radar by : National Research Council
Download or read book Laser Radar written by National Research Council and published by National Academies Press. This book was released on 2014-03-14 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: In today's world, the range of technologies with the potential to threaten the security of U.S. military forces is extremely broad. These include developments in explosive materials, sensors, control systems, robotics, satellite systems, and computing power, to name just a few. Such technologies have not only enhanced the capabilities of U.S. military forces, but also offer enhanced offensive capabilities to potential adversaries - either directly through the development of more sophisticated weapons, or more indirectly through opportunities for interrupting the function of defensive U.S. military systems. Passive and active electro-optical (EO) sensing technologies are prime examples. Laser Radar considers the potential of active EO technologies to create surprise; i.e., systems that use a source of visible or infrared light to interrogate a target in combination with sensitive detectors and processors to analyze the returned light. The addition of an interrogating light source to the system adds rich new phenomenologies that enable new capabilities to be explored. This report evaluates the fundamental, physical limits to active EO sensor technologies with potential military utility; identifies key technologies that may help overcome the impediments within a 5-10 year timeframe; considers the pros and cons of implementing each existing or emerging technology; and evaluates the potential uses of active EO sensing technologies, including 3D mapping and multi-discriminate laser radar technologies.
Book Synopsis Optical Techniques for Millimeter-wave Detection and Imaging by : Christopher Arnim Schuetz
Download or read book Optical Techniques for Millimeter-wave Detection and Imaging written by Christopher Arnim Schuetz and published by ProQuest. This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The benefits of imaging using regions of the electromagnetic spectrum outside the visible range have been known for decades. Infrared and radio frequency imaging techniques have achieved great successes in both military and civilian applications. However, there remains a range of the spectrum between these two regimes that remains relatively unexplored. Millimeter waves, or the range of wavelengths between one millimeter and one centimeter, have remained relatively unexplored as an imaging technology, largely due to the lack of sufficiently sensitive, practical detectors for passive imaging in this regime. At these short wavelengths, the diffraction limit imposed by the limited extent of the imaging aperture significantly limits attainable image resolution. Recent developments in semiconductor low-noise amplifiers have demonstrated many desirable applications for such imaging technology, but have, as yet, not been able to demonstrate the economical, small-format imagers necessary to make such imagers practical in most of the conceived applications. In this regard, I present a new approach to millimeter-wave detection based on optical modulation with subsequent carrier suppression. This approach demonstrates promise in achieving the goal of economical, high-resolution imagers with sufficient sensitivity for passive millimeter-wave imaging. In this thesis, I explain the operational requirements of such detectors, provide theoretical background for their operation, and describe current experimental results obtained using commercially available components in the 35 GHz. In addition, I describe successful efforts to fabricate modulators with improved modulation bandwidths for detection in the 95 GHz atmospheric window. These demonstration systems have attained sufficient single pixel performance to detect thermal emission with a noise equivalent temperature difference (NETD) approaching 1K/[Special characters omitted.] at both 35 and 95 GHz. The NETDs attained correspond to sub-picowatt noise equivalent powers which, to the best of my knowledge, have never before been obtained without the use of millimeter-wave low noise amplifiers or cryogenic cooling. The described optically-based detection technique has also demonstrated unique advantages to overcoming the resolution limits imposed by aperture size. Since the optical upconversion process preserves the phase of the collected energy, coherent imaging methods are possible. This enables the use of distributed aperture imaging, which could potentially provide large effective apertures for high resolution without the associated volumetric scaling associated with traditional focal plane arrays. Optical fiber can be utilized to provide low-loss, dispersion-free routing of the upconverted energy and optical lenses and cameras can be used to reconstruct the sampled image in a relatively simple manner. The combination of these factors offers potential for a uniquely capable millimeter-wave imaging technology based on optical upconversion. As part of this dissertation, I describe the relevant parameters that must be considered in designing such an imager and present results from a prototype array that has been successfully demonstrated.
Book Synopsis Passive Millimeter-wave Imaging Technology by :
Download or read book Passive Millimeter-wave Imaging Technology written by and published by . This book was released on 2001 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Passive Millimeter-Wave Imaging Technology IX by :
Download or read book Passive Millimeter-Wave Imaging Technology IX written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Technology for Advanced Focal Plane Arrays of HgCdTe and AlGaN by : Li He
Download or read book Technology for Advanced Focal Plane Arrays of HgCdTe and AlGaN written by Li He and published by Springer. This book was released on 2016-07-15 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the basic framework of advanced focal plane technology based on the third-generation infrared focal plane concept. The essential concept, research advances, and future trends in advanced sensor arrays are comprehensively reviewed. Moreover, the book summarizes recent research advances in HgCdTe/AlGaN detectors for the infrared/ultraviolet waveband, with a particular focus on the numerical method of detector design, material epitaxial growth and processing, as well as Complementary Metal-Oxide-Semiconductor Transistor readout circuits. The book offers a unique resource for all graduate students and researchers interested in the technologies of focal plane arrays or electro-optical imaging sensors.
Book Synopsis Program for Field Validation of the Synthetic Aperture Focusing Technique for Ultrasonic Testing (SAFT UT) by : Jerry Lee Jackson
Download or read book Program for Field Validation of the Synthetic Aperture Focusing Technique for Ultrasonic Testing (SAFT UT) written by Jerry Lee Jackson and published by . This book was released on 1981 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Superresolution of Passive Millimeter-Wave Imaging by :
Download or read book Superresolution of Passive Millimeter-Wave Imaging written by and published by . This book was released on 2000 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project develops methods for image acquisition that will provide superresolution capability without the benefit of assumptions about the object intensity distribution. Superresolution is of particular interest in passive millimeter wave imaging, which has tremendous potential for imaging in adverse conditions but suffers from poor resolution. Because of the finite aperture in PMMW, the acquired image is strictly bandlimited. Therefore, an important issue is sampling pattern optimization. Ordinarily, a focal plane sensor array has sensors placed in a rectangular grid pattern at sub-Nyquist density, and the must be dithered to sample the image plane at the Nyquist density in each dimension. However, the Nyquist density oversamples the image due to the usually circular support of the diffraction-limited image spectrum. We have developed an efficient algorithm for optimizing the dithering pattern so that the image can be reconstructed reliably from a less dense periodic nonuniform set of samples, which can be obtained from a dithered rectangular-grid array. The resulting algorithm can be used to explore image acquisition strategies. We have also investigated optimizing the aperture sensitivity to shape the spatial frequency response of the acquisition system. Preliminary results indicate only marginal improvement. However, under certain circumstances, as in the case where edge detection is the primary task for imaging, more significant improvement may be achieved.
Book Synopsis Passive Millimeter-wave Imaging Technology IV by : Roger M. Smith
Download or read book Passive Millimeter-wave Imaging Technology IV written by Roger M. Smith and published by Society of Photo Optical. This book was released on 2000 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Passive Millimeter-wave Imaging Technology by : Roger M. Smith
Download or read book Passive Millimeter-wave Imaging Technology written by Roger M. Smith and published by Society of Photo Optical. This book was released on 1997 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Electrical & Electronics Abstracts by :
Download or read book Electrical & Electronics Abstracts written by and published by . This book was released on 1997 with total page 1860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Generation and Detection of Millimeter-wave Optical Signals for Use in Power-combining Arrays by : Andrew Charles Davidson
Download or read book Generation and Detection of Millimeter-wave Optical Signals for Use in Power-combining Arrays written by Andrew Charles Davidson and published by . This book was released on 1997 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: About 60 GHz IMPATT oscillator array with pulsed operation, photoconductive sampling with an integrated loop, GaInAs MSM photodetectors with Cu Schottky contacts, and multi-laser phase-locked loops.
Author :Society of Photo-optical Instrumentation Engineers Publisher :Society of Photo Optical ISBN 13 :9780819428271 Total Pages :178 pages Book Rating :4.4/5 (282 download)
Book Synopsis Passive Millimeter-wave Imaging Technology II by : Society of Photo-optical Instrumentation Engineers
Download or read book Passive Millimeter-wave Imaging Technology II written by Society of Photo-optical Instrumentation Engineers and published by Society of Photo Optical. This book was released on 1998 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of works on passive millimetre-wave imaging technology includes papers on passive millimetre-wave imaging systems, passive millimetre-wave component technology, passive millimetre-wave modeling and phenomenology and passive millimetre-wave resolution enhancement/superresolution.
