Faculty Publications

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Subject: search.filters.subject.Beamforming

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    Area and power optimised ASIC implementation of adaptive beamformer for hearing AIDS
    (Institute of Electrical and Electronics Engineers Inc., 2017) Samtani, K.; Thomas, J.; Deepu, S.P.; Sumam David, S.
    Beamforming is a technique used in hearing AIDS to improve the intelligibility of target sound by reducing the interference from other directions. An efficient ASIC implementation of a two omnidirectional microphone array based adaptive beamforming algorithm is presented in this paper with various optimisations proposed at different stages of the hardware design. The beamform patterns and improvements in SNR values obtained from experiments conducted in a conference room environment were analysed to verify the working of the design. The architecture was implemented with 0.18 μm standard cell libraries. Cell area and power reports were analysed for different optimisations. The final area and power obtained are 0.054 mm2 and 60.54 μW respectively. © 2017 IEEE.
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    Highly steerable microwave beamforming system near Ku band based on the application of linearly CFBG
    (Institution of Engineering and Technology jbristow@theiet.org, 2020) Raghuwanshi, S.K.; Srivastava, N.K.; Singh, M.
    In this study, the authors present theoretical and experimental results of wideband beamforming networks steered by a single linear chirped fibre Bragg grating (CFBG). The standard single-sideband modulation technique is followed to validate the wideband (at 18 GHz) operation of the proposed system. CFBG has been fabricated by phase mask technology for the desired specification to be compatible with the antenna array. To the authors knowledge, the effect of dispersion slope feature of fabricated FBG on the performance of beam-steering capability of the antenna is reported for the first time in this study. Theoretically preceded by experimental testing, it was found that the scanning angle increased with the rise in the number of antenna elements and the frequency of modulating microwave signal. © 2019 The Institution of Engineering and Technology.
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    Variational mode decomposition based image denoising using semi-adaptive conductance function inspired diffusion filtering
    (Springer, 2024) Gupta, H.; Singh, H.; Kumar, A.; Vishwakarma, A.; Singh, G.K.
    In day-to-day life, images are the most frequent and casual way of information sharing. These images are susceptible to external disturbances or noise. Thus, to curb noise, image denoising algorithms are utilized. In this paper, the variational mode decomposition, with its concurrent and a non-recursive process for determining the mode functions that also provides a robust method for image denoising, has been introduced. This decomposition process divides the whole spectrum of the signal into a number of sub-bands or mode functions, centered around their respective center frequencies. To these mode functions, spatial filters such as bilateral filter, wiener filter, and modified anisotropic diffusion filter are employed. These filters help in enhancing the yield of the quality assessment metrics; such as mean square error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index (SSIM), together with the semi-adaptive conductance function in the diffusion filter. The parameters of these respective spatial filters are calibrated, and then selected in order to get the best possible metric scores. The applicability and ability of the algorithm to suppress noise are compared visually and quantitatively for the noisy image using modified variational mode decomposition and other denoising algorithms in both low and high noise levels. The algorithm provides an average decrease of 62% in case of MSE, 28% increase in PSNR, and 110% increase in SSIM when compared with other denoising techniques. The estimated metric score values signify that the proposed method has a better prospect as a denoising algorithm. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.