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Browsing by Author "Prasad, B. R"

Browsing by Author "Prasad, B. R"

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  • The Aditya-L1 mission of ISRO 
    Tripathi, Durgesh; Chakrabarty, D; Nandi, A; Prasad, B. R; Ramaprakash, A. N; Shaji, Nigar; Sankarasubramanian, K; Satheesh Thampi, R; Yadav, V. K (Cambridge University Press on behalf of International Astronomical Union, 2023)
    The Aditya-L1 is the first space-based solar observatory of the Indian Space Research Organization (ISRO). The spacecraft will carry seven payloads providing uninterrupted observations of the Sun from the first Lagrangian ...
  • Advanced Methods for Improving the Efficiency of a Shack Hartmann Wavefront Sensor 
    Vyas, A; Roopashree, M. B; Prasad, B. R (InTech, 2012-01)
  • Automated ROI selection and calibration of a microlens array using a MEMS CDM 
    Roopashree, M. B; Vyas, A; Prasad, B. R (Optical Society of America, 2011-07)
    A method of automated selection of region of interest for sensing using a microlens array by imposing Zernikes on a 140 actuator deformable mirror is presented. The positional sensitivity and optimal noise removal techniques ...
  • Band-limited integrated scatter measurements on super polished optical mirrors 
    Ventaka, S; Prasad, B. R; Natarajan, V; Kamath, P. U; Kathiravan, S (SPIE-The International Society for Optical Engineering, 2020-08)
    Scattering of light from a surface depends on its microroughness. In general, total integrated scattering of a surface is expressed in terms of root-mean-square microroughness (σrms) using empirical relations. These ...
  • Calibration of Spectropolarimetry package for Visible Emission Line Coronagraph (VELC) on board Aditya-L1 mission 
    Venkata Suresh, Narra; Hegde, Bhavana; Dasamantarao, Utkarsha; Somasundaram, P. K; Kamath, P. U; Prasad, B. R (World Scientific Publishing Company, 2023-12)
    Visible Emission Line Coronagraph (VELC) is the prime payload on board Aditya-L1 mission. One of the unique capabilities of VELC is the coronal magnetic field measurements from space. To achieve this, VELC performs dual ...
  • Calibration of VELC detectors on-board Aditya-L1 mission 
    Mishra, Shalabh; Sasikumar Raja, K; Sanal Krishnan, V. U; Venkata Suresh, Narra; Hegde, Bhavana; Utkarsha, D; Priyal, M; Pawan, Kumar; Natarajan, V; Prasad, B. R; Singh, J; Kamath, P. U; Kathiravan, S; Vishnu, T; Suresha; Savarimuthu, P; Desai, Jalshri H; Kumaran, Rajiv; Sagar, Shiv; Kumar, Sumit; Bamrah, Inderjeet Singh; Amit Kumar (Springer Nature, 2024-04)
    Aditya-L1 is the first Indian space mission to explore the Sun and solar atmosphere with seven multi-wavelength payloads, with Visible Emission Line Coronagraph (VELC) being the prime payload. It is an internally occulted ...
  • Centroid detection by Gaussian pattern matching in adaptive optics 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Foundation of Computer Science, 2010)
    Shack Hartmann wavefront sensor is a two dimensional array of lenslets which is used to detect the incoming phase distorted wavefront through local tilt measurements made by recording the spot pattern near the focal plane. ...
  • Comparison of optical powerlimiting in bacteriorhodopsin and Azo-benzene films 
    Jagadish, C. S; Turaga, P. S; Prasad, B. R; Sivasankara Sai, S (Department of Applied Optics and photonics, University of Calcutta, 2009)
    In this paper a comparison of the optical power-limiting characteristics of Bacteriorhodopsin (bR) and Azobenzcnc films is reported. An attempt is made to find out the technique which gives best powerlimiting for each of ...
  • Contamination control of UVIT 
    Kathiravan, S; Tandon, S. N; Prasad, B. R; Sriram, S; Pradeep, A; Vishnu, T; Mahesh, P. K; Kamath, P. U; Nagabhushana, S; Amit Kumar (Indian Academy of Sciences, 2021-10)
    Ultra Violet Imaging Telescope (UVIT) is one of the 5 instruments on AstroSat satellite, which was launched on September 28, 2015. UVIT was designed to make images with a resolution of <1.8′′, simultaneously in two ultraviolet ...
  • Data pipeline architecture and development for VELC onboard Space Solar Mission AdityaL1 
    Singh, J; Prasad, B. R; Sumana, Chavali; Amit Kumar; Varun Kumar; Priyal, Muthu; Venkata Suresh, Narra (Elsevier Ltd., 2022-03-15)
    ADITYA L-1 is India’s first dedicated mission to study Sun and its atmosphere with Visible Emission Line Coronagraph (VELC), a major payload on ADITYA-L1. VELC has provision to make imaging and spectroscopic observations ...
  • Denoising Shack Hartmann sensor spot pattern using zernike reconstructor 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Macmillan Publishers India Ltd., 2009)
    Shack Hartmann Sensor (SHS) is inflicted with significant background noise that deteriorates the wave-front reconstruction accuracy. In this paper, a simple method to remove the back ground noise with the use of Zernike ...
  • Design and analysis of an FUV spectrograph for a small satellite 
    Munshi, R; Prasad, B. R; Murthy, J (Astronomical Society of India, 2009-06)
    The Halo Ultraviolet Explorer (HUE) is a payload aimed at studying the diffuse far ultraviolet sky over a bandpass of 800 -- 1200 Ao. The novel features of HUE include a large effective collecting area (254 cm2) and fast ...
  • Digital long focal length lenslet array using spatial light modulator 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    Under a thin lens and paraxial approximation, the phase transformation function of a lens was simulated on a Liquid Crystal (LC) based Spatial Light Modulator (SLM). The properties of an array of such lenses simulated ...
  • Dither-based sensor for improved consistency of adaptive optics system 
    Vyas, A; Roopashree, M. B; Prasad, B. R (SPIE--The International Society for Optical Engineering, 2010-07)
    The wavefront reconstruction accuracy in Shack Hartmann sensor based adaptive optics system depends on accurate centroiding and phase estimation from measured slope values. Monte Carlo simulations of vector matrix multiply ...
  • Effective coherence length estimation of optical wavefronts 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    In adaptive optics, the measurement of spatial coherence length helps in deciding the optimum design parameters of a Shack Hartmann Sensor (SHS). Two methods of estimating the spatial coherence length of optical wavefronts ...
  • Efficient minimization of servo lag error in adaptive optics using data stream mining 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Springer, 2011)
    Prediction of the wavefronts helps in reducing the servo lag error in adaptive optics caused by finite time delays (~ 1-5 ms) before wavefront correction. Piecewise linear segmentation based prediction is not suitable in ...
  • Evaluation of the performance of centroiding algorithms with varying spot size: case of WFS calibration for the TMT NFIRAOS 
    Vyas, A; Ellerbroek, B. L; Roopashree, M. B; Andersen, D. R; Prasad, B. R (Optical Society of America, 2011-07)
    In this AO system, a low-bandwidth truth wavefront sensor detects biases in the laser-guide-star-based wavefront measurement, arising from uncertainties in the sodium layer profile. Here, the performance of centroiding ...
  • Experimental evaluation of centroiding algorithms at different light intensity and noise levels 
    Roopashree, M. B; Vyas, A; Prasad, B. R (American Institute of Physics, 2011-10)
    In this paper, we present results from an experimental evaluation of centroiding algorithms, simple center of gravity (CoG) and weighted center of gravity (WCoG) in a Shack Hartmann wavefront sensor at different light ...
  • Experimental Validation of a Novel Concept to Reduce Optical Surface Wave Front Errors by Using Deformable Bushes at Opto-Mechanical Interfaces 
    Nagabhushana, S; Prasad, B. R; Nagesh, Suresh; Venkata Suresh, Narra; Sandeep, D. S; Kamath, P. U; Misra, Shalab; Hegde, Bhavana; Utkarsha, D; Sinha, Mrityunjay Kumar; Kathiravan, S; Natarajan, V; Pawan, Kumar; Amit Kumar (World Scientific Publishing, 2022-03)
    One of the major objectives of the optomechanics is to support large optics required for the purpose and also to maintain high dynamic stability in operation. This requirement calls for more number of supports, to support ...
  • Exploring the outer emission corona spectroscopically by using Visible Emission Line Coronagraph (VELC) on board ADITYA-L1 mission 
    Singh, J; Prasad, B. R; Venkata Suresh, Narra; Amit Kumar (Elsevier B.V, 2019-07-17)
    It is very important to make the spectrographic observations of the outer emission corona in number of emission lines simultaneously in view of the results of the observations made in [Fe x] 6374 A, [Fe xi] 7892 A, [Fe ...

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