Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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Author: search.filters.author.D'Souza, J.Has files: No

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    Super resolution of video with sharpened edges using multiple frames - A novel approach
    (2009) Pais, A.R.; D'Souza, J.; Guddeti, G.R.M.; Patil, S.B.
    In most electronic video applications, video with Higher Resolution(HR) are often required. HR video can offer more details that may be critical in various applications like Video Surveillance. Super resolution technique refers to generation of high resolution image from low resolution image by adding some extra information. Super resolution allows us to reduce the need of extra hardware to obtain HR image. This paper proposes a new method for super resolution video generation with sharpened edges using multiple frames. Unique information present in subpixel shifted frames is extracted and used for frequency domain registration process. © 2009 IEEE.
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    Automatic video object plane segmentation and super resolution: A novel approach
    (2009) Pais, A.R.; Pasupuleti, N.; Gidnavar, R.; D'Souza, J.
    Detecting, segmenting and super resolving of moving object is an important subject in computer visual analysis and surveillance. This paper discusses automatic VOP (Video Object Plane) segmentation and super resolving of VOP. We have proposed a new method for automatic generation of VOP by using block matching and quantization techniques. Edge model based approach is used to generate the HR (High Resolution) image with sharper VOP boundaries. Experimental results show that the proper VOP is segmented and super resolution of VOP yields lesser blurring compared to bicubic, bilinear interpolation schemes. Copyright © 2009 by IICAI.
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    Performance of spatially coupled LDPC codes over underwater acoustic communication channel
    (Institute of Electrical and Electronics Engineers Inc., 2020) Padala, S.K.; D'Souza, J.
    Underwater acoustic (UWA) channel is complex because of its multipath environment, Doppler shift and rapidly changing characteristics. Many of the UWA communication- based applications demand high data rates and reliable communication. The orthogonal frequency division multiplexing (OFDM) system is very effective in UWA channels and provides high data rate with low equalization complexity. It is a challenging task to achieve reliability over these channels. The low-density parity-check (LDPC) codes give a better error performance than turbo codes, for UWA channels. The spatially-coupled low-density parity-check (SC-LDPC) codes have been shown to have the capacity-achieving performance over terrestrial communication. In this paper, we have studied by simulation, the performance of protograph based SC-LDPC codes over shallow water acoustic environment with a communication range of 1000 m and channel bandwidth of 10 KHz. Our results show that SC-LDPC codes give 1 dB performance improvement over LDPC codes at a Bit Error Rate (BER) of 10-3 for the same latency constraints. © 2020 IEEE.
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    Nonlinear Frequency Modulated Waveform Optimization for a Cooperative Radar-Communication System
    (Institute of Electrical and Electronics Engineers Inc., 2021) Mahipathi, A.C.; Gunnery, S.; Srihari, P.; D'Souza, J.; Jena, P.
    Co-existence research related to radar and communication systems has gained significant interest in the last decade to address the spectrum scarcity issues. Designing an optimal waveform for a Joint Radar-Communication (JRC) system is an important consideration to practically realize the convergence of these two subsystems. This paper proposes a Power Ratio Constraint (PRC) based optimization technique to evaluate phase coefficients of Non Linear Frequency Modulated (NLFM) waveform for a Cooperative Radar-Communication System (CRCS). The radar waveform is optimized here using the Cramér-Rao Lower Bound (CRLB) metric in conjunction with the PRC. We investigated the spectral energy distribution, auto correlation function, and estimation rate for radar systems using optimized NLFM waveform phase coefficients. In addition, data rate for communication system is computed. Further, the simulation results shows that, proposed joint PRC-CRLB based optimization method confines the radar spectrum, reduces the delay ambiguities and enhances the information rate of CRCS. © 2021 IEEE.
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    LPI-Based NLFM Radar Waveform Design for a Cooperative Radar-Communication System
    (Institute of Electrical and Electronics Engineers Inc., 2023) Mahipathi, A.C.; Pardhasaradhi, B.; Srihari, P.; D'Souza, J.; Jena, P.
    This paper studies the Low Probability of Intercept (LPI) based Non-Linear Frequency Modulated (NLFM) radar waveform design approach in a Cooperative Radar-Communication System (CRCS). The crux of the LPI-based radar waveform design approach is to employ optimization methods to design the transmitted radar waveform for achieving the LPI characteristics by upholding the target detection characteristics. Here, the optimization problem is formulated subject to the Power Constraint (PC) (responsible for LPI characteristics) and Similarity Constraint (SC) (responsible for target detection) to guarantee a satisfactory performance in a CRCS. In addition, the simulation results exhibit that the proposed LPI-based NLFM radar waveform design approach provides desired characteristics needed to maintain the LPI and target detection performance in a CRCS. © 2023 IEEE.