• Adaptive Feature-Specific Spectral Imaging Classifier (AFSSI-C)

      Gehm, Michael; Dunlop, Matthew; Poon, Phillip; University of Arizona (International Foundation for Telemetering, 2013-10)
      The AFSSI-C is a spectral imager that generates spectral classification directly, in fewer measurements than are required by traditional systems that measure the spectral datacube (which is later interpreted to make material classification). By utilizing adaptive features to constantly update conditional probabilities for the different hypotheses, the AFSSI-C avoids the overhead of directly measuring every element in the spectral datacube. The system architecture, feature design methodology, simulation results, and preliminary experimental results are given.
    • Calibration of High Dimensional Compressive Sensing Systems: A Case Study in Compressive Hyperspectral Imaging

      Gehm, Michael; Poon, Phillip; Dunlop, Matthew; University of Arizona (International Foundation for Telemetering, 2013-10)
      Compressive Sensing (CS) is a set of techniques that can faithfully acquire a signal from sub- Nyquist measurements, provided the class of signals have certain broadly-applicable properties. Reconstruction (or exploitation) of the signal from these sub-Nyquist measurements requires a forward model - knowledge of how the system maps signals to measurements. In high-dimensional CS systems, determination of this forward model via direct measurement of the system response to the complete set of impulse functions is impractical. In this paper, we will discuss the development of a parameterized forward model for the Adaptive, Feature-Specific Spectral Imaging Classifier (AFSSI-C), an experimental compressive spectral image classifier. This parameterized forward model drastically reduces the number of calibration measurements.
    • Collar-Integrated Small Mammal GPS Tracker

      Marcellin, Michael; Melde, Kathleen; Kundu, Ina; Rice, Sean; Klug, Kevin; Chen, Hao; Marquez, Elizabeth; Zhong, Yizhou; University of Arizona (International Foundation for Telemetering, 2013-10)
      A position beaconing system for tracking small mammals, such as the Golden Lion Tamarin, was developed and tested. GPS acquires location of the animal. The system utilizes a VHF radio transmitter tuned to 144.390 MHz, which is located in the amateur radio band. APRS was selected as the protocol for position, transmission, and recovery. This allows users to benefit from any existing APRS enabled devices. The beacon was designed by attempting to optimize operational longevity and minimize size. Consequently, the system is implemented on a single board and enclosed for protection. As the system must be comfortable for the mammal, it was manufactured from lightweight components and enclosed in a plastic housing. To attach the case to the mammal, it is connected to a flexible, zig-zag, wearable antenna, which functions as a collar.
    • combined Modulation and Error Correction Decoder for TDMR Using Generalized Belief Propagation

      Vasić, Bane; Khatami, Mehrdad; University of Arizona (International Foundation for Telemetering, 2013-10)
      Constrained codes also known as modulation codes are a key component in the digital magnetic recording systems. The constrained codes forbid particular input data patterns which lead to some of the dominant error events or higher media noise. In data recording systems, a concatenated approach toward the constrained code and error-correcting code (ECC) is typically used and the decoding is done independently. In this paper, we show the improvement in combining the decoding of the constrained code and the ECC using generalized belief propagation (GBP) algorithm. We consider the performance of a combined modulation constraints and the ECC on a binary symmetric channel (BSC). We show that combining demodulation and decoding results in a superior performance compared to concatenated schemes. Furthermore, we compute the capacity of the joint ECC and modulation codes for 1-D and 2-D constraints.
    • Direction of Arrival Estimation Improvement for Closely Spaced Electrically Small Antenna Array

      Xin, Hao; Yu, Xiaoju; University of Arizona (International Foundation for Telemetering, 2013-10)
      In this paper, a new technique utilizing a scatterer of high dielectric constant in between electrically small antennas to achieve good Direction of arrival (DOA) estimation performance is demonstrated. The phase information of the received signal at the antennas is utilized for direction estimation. The impact of the property of the scatterer on the directional sensitivity and the output signal to noise ratio (SNR) level are studied. Finally the DOA estimation accuracy is analyzed with the proposed technique under the consumption of white Gaussian noise environment.
    • Low-Complexity Iterative Reconstruction Algorithms in Compressed Sensing

      Vasić, Bane; Marcellin, Michael W.; Declercq, David; Danjean, Ludovic; University of Arizona (International Foundation for Telemetering, 2013-10)
      In this paper we focus on two low-complexity iterative reconstruction algorithms in compressed sensing. These algorithms, called the approximate message-passing algorithm and the interval-passing algorithm, are suitable to recover sparse signals from a small set of measurements. Depending on the type of measurement matrix (sparse or random) used to acquire the samples of the signal, one or the other reconstruction algorithm can be used. We present the reconstruction results of these two reconstruction algorithms in terms of proportion of correct reconstructions in the noise free case. We also report in this paper possible practical applications of compressed sensing where the choice of the measurement matrix and the reconstruction algorithm are often governed by the constraint of the considered application.
    • Machine Vision and Autonomous Integration Into an Unmanned Aircraft System

      Dianics, James; Fasel, Hermann F.; Marcellin, Michael W.; Van Horne, Chris; University of Arizona (International Foundation for Telemetering, 2013-10)
      The University of Arizona's Aerial Robotics Club (ARC) sponsors the development of an unmanned aerial vehicle (UAV) able to compete in the annual Association for Unmanned Vehicle Systems International (AUVSI) Seafarer Chapter Student Unmanned Aerial Systems competition. Modern programming frameworks are utilized to develop a robust distributed imagery and telemetry pipeline as a backend for a mission operator user interface. This paper discusses the design changes made for the 2013 AUVSI competition including integrating low-latency first-person view, updates to the distributed task backend, and incremental and asynchronous updates the operator's user interface for real-time data analysis.
    • Near Field Wireless Power Transmission

      Xin, Hao; Marcellin, Michael; Sanders, Ivar; Althawab, Meshal; Eberhard, Jared; Hernandez, Alan; Manos, John; Patel, Aniket; Tavour, Alex; von Oppenfeld, Christian; et al. (International Foundation for Telemetering, 2013-10)
      A prototype wireless power transfer system using the near field to transfer energy between resonantly tuned coils, in order to charge a cell phone or other small electronic device. The system uses resonance to ensure maximum wireless power transfer efficiency between the two coils, and gain greater flexibility in distance between the two coils. The frequency of power transfer is in the unregulated 6.78MHz ISM band. The system is monitored and controlled by an Arduino, and shuts off power when the system does not detect a load.
    • Optical Orbital Angular Momentum for Secure and Power Efficient Point-to-Point FSO Communications

      Alfowzan, Mohammed; Khatami, Mehrdad; Vasic, Bane; University of Arizona (International Foundation for Telemetering, 2013-10)
      We address the problem of detection in orbital angular momentum (OAM). The focus of our analysis will be on the power efficient Q-ary Pulse Position Modulation (Q - PPM). Free space optical signals sent through wireless channels are degraded by atmospheric turbulence. In this paper a novel detection approach based on a factor graph representation of OAM Q-PPM signalling is presented to equalize for the crosstalk among orbital angular momentum vortices. It will be shown that our proposed detection algorithm significantly outperforms the separate detection scenario in terms of error rate performance.
    • Spread Spectrum Signal Detection from Compressive Measurements

      Marcellin, Michael W.; Goodman, Nathan A.; Bilgin, Ali; Lui, Feng; University of Arizona (International Foundation for Telemetering, 2013-10)
      Spread Spectrum (SS) techniques are methods used to deliberately spread the spectrum of transmitted signals in communication systems. The increased bandwidth makes detection of these signals challenging for non-cooperative receivers. In this paper, we investigate detection of Frequency Hopping Spread Spectrum (FHSS) signals from compressive measurements. The theoretical and simulated performances of the proposed methods are compared to those of the conventional methods.
    • Validation for Visually lossless Compression of Stereo Images

      Marcellin, Michael W.; Bilgin, Ali; Feng, Hsin-Chang; University of Arizona (International Foundation for Telemetering, 2013-10)
      This paper described the details of subjective validation for visually lossless compression of stereoscopic 3 dimensional (3D) images. The subjective testing method employed in this work is adapted from methods used previously for visually lossless compression of 2 dimensional (2D) images. Confidence intervals on the correct response rate obtained from the subjective validation of compressed stereo pairs provide reliable evidence to indicate that the compressed stereo pairs are visually lossless.