• Joint JPEG2000/LDPC Code System Design for Image Telemetry

      Ryan, William E.; Marcellin, Michael W.; Bilgin, Ali; Jagiello, Kristin; Aydin, Mahmut Zafer; Ng, Wei-Ren; University of Arizona (International Foundation for Telemetering, 2008-10)
      This paper considers the joint selection of the source code rate and channel code rate in an image telemetry system. Specifically considered is the JPEG2000 image coder and an LDPC code family. The goal is to determine the optimum apportioning of bits between the source and channel codes for a given channel signal-to-noise ratio and total bit rate, R(total). Optimality is in the sense of maximum peak image SNR and the tradeoff is between the JPEG2000 bit rate R(source) and the LDPC code rate R(channel). For comparison, results are included for the industry standard rate-1/2, memory-6 convolutional code.
    • On Guaranteed Error Correction Capability of GLDPC Codes

      Vasic, Bane; Marcellin, Michael W.; Chilappagari, Shashi Kiran; Nguyen, Dung Viet; University of Arizona (International Foundation for Telemetering, 2008-10)
      In this paper, it is shown that generalized LDPC codes can correct a linear fraction of errors under the parallel bit flipping algorithm when the underlying Tanner graph is a good expander. A lower bound on the size of variable node sets which have required expansion is established as a function of the column weight of the code, the girth of the Tanner graph and the error correction capability of the sub-code. It is also shown that the bound on the required expansion cannot be improved when the column weight is even by studying a class of trapping sets. An upper bound on the guaranteed error correction capability is found by investigating the size of smallest possible trapping sets.
    • Scalable Perceptual Image Coding for Remote Sensing Systems

      Marcellin, Michael W.; Bilgin, Ali; Oh, Han; Lalgudi, Hariharan G.; University of Arizona (International Foundation for Telemetering, 2008-10)
      In this work, a scalable perceptual JPEG2000 encoder that exploits properties of the human visual system (HVS) is presented. The algorithm modifies the final three stages of a conventional JPEG2000 encoder. In the first stage, the quantization step size for each subband is chosen to be the inverse of the contrast sensitivity function (CSF). In bit-plane coding, two masking effects are considered during distortion calculation. In the final bitstream formation step, quality layers are formed corresponding to desired perceptual distortion thresholds. This modified encoder exhibits superior visual performance for remote sensing images compared to conventional JPEG2000 encoders. Additionally, it is completely JPEG2000 Part-1 compliant, and therefore can be decoded by any JPEG2000 decoder.
    • Wireless Sensor Networks: A Grocery Store Application

      Marcellin, Michael W.; Xin, Hao; Chaves, Andrea; Mayoral, Bruno; Park, Hyun-Jin; Tsang, Mark; Tunell, Sean; University of Arizona (International Foundation for Telemetering, 2008-10)
      This paper explains the development of a wireless network system implemented to streamline grocery store checkout procedures. The design employs a wireless telemetry network consisting of a base station and wireless motes (Micaz MPR2400) that will be located on certain aisles, and attached to shopping carts. This system allows customers to scan items while they shop and uses cashiers for payment purposes only. The objective is to minimize the amount of processing performed by cashiers in order to reduce waiting times in line. The system was tested in a simulation environment and waiting times were reduced by 65%.