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Optical Metrology and Imaging Laboratory

Welcome to the Optical Metrology and Imaging Laboratory (OMIL) at IIT Kanpur. Our goal is to develop novel optical techniques for precision metrology. The relevant application areas include surface characterization, 3D shape sensing, non-destructive inspection and cell imaging.

Faculty

I am Prof. Gannavarpu Rajshekhar. I am jointly affiliated with the Department of Electrical Engineering and Center for Lasers and Photonics at IIT Kanpur.

Education

PhD, Photonics (2009-2012)
Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland

Master of Technology, Laser Technology (2006-2008)
Indian Institute of Technology, Kanpur, India

Bachelor of Engineering, Electronics and Telecommunication Engineering (2001-2005)
Government Engineering College Raipur (now NIT Raipur), Pt. Ravishankar Shukla University, Raipur, India

Experience

Associate Professor (2018-present)
Department of Electrical Engineering, IIT Kanpur

Assistant Professor (2014-2018)
Department of Electrical Engineering, IIT Kanpur

Swiss National Science Foundation Postdoctoral Fellow (2013-2014)
Beckman Institute, University of Illinois at Urbana-Champaign, USA

Postdoctoral Researcher (2012-2013)
Applied Computing and Mechanics Laboratory, EPFL, Switzerland

Awards

Service

Teaching

Undergraduate Courses

Postgraduate Courses

Research

Area

We work in the domain of optical coherent imaging. Here, we are mainly interested in quantitatively measuring the phase of the optical wave-field scattered from an object or specimen. We work on both the experimental and computational aspects of coherent imaging.

The experimental techniques being investigated in the lab involve:

The computational research involves the development of robust signal processing techniques in optical imaging. Some relevant problems include:

Applications

Students

Phd

  1. Allaparthi Venkata Satya Vitin
  2. Dhruvam Pandey
  3. K. N. Subhramanya

M.Tech

  1. Viren S Ram
  2. Apurva Jayant
  3. Kshitiz Srivastava

MSR

  1. Avinash Chowdhary

Alumni

PhD

  1. Ajithaprasad Sreeprasad (2021)
  2. Ankur Vishnoi (2021)
  3. Ramaiah Jagadesh (2022)

M.Tech

  1. Rahul Sinha (2017)
  2. Velpula Raviteja (2017)
  3. Vinit Vijay (2018)
  4. Allaparthi Vitin (2018)
  5. Vigneshwar Rajendran (2019)
  6. Issac Shaw (2019)
  7. Dhruvam Pandey (2020)
  8. Achraj Satsangi (2020)
  9. Abhinav Saini (2021)
  10. Amit Kumar Singh (2021)
  11. Sriram Suresh (2022)
  12. Niket (2022)
  13. Dhananjay Pandey (2022)
  14. Ankit Kumar (2022)

MSR

  1. Aditya Madipadaga (2021)

Publications

Journals

  1. Allaparthi Venkata Satya Vithin and Rajshekhar Gannavarpu, Quantitative phase gradient metrology using diffraction phase microscopy and deep learning, Journal of the Optical Society of America A, 40(3), 611-619, 2023

  2. Allaparthi Venkata Satya Vithin, Jagadesh Ramaiah, and Rajshekhar Gannavarpu, Deep learning based single shot multiple phase derivative retrieval method in multi-wave digital holographic interferometry, Optics and Lasers in Engineering, 162, 107442, 2023

  3. Jagadesh Ramaiah, Tullio de Rubeis, Rajshekhar Gannavarpu and Dario Ambrosini, Quantitative flow visualization by hidden grid background oriented schlieren, Optics and Lasers in Engineering, 160, 107307, 2023

  4. Dhruvam Pandey, Jagadesh Ramaiah, Sreeprasad Ajithaprasad and Rajshekhar Gannavarpu, Subspace analysis based machine learning method for automated defect detection from fringe patterns, Optik, 270, 170026, 2022

  5. Jagadesh Ramaiah and Rajshekhar Gannavarpu, Multiple phase extraction using graphics processing unit assisted unitary transformation method in digital holographic interferometry, Applied Optics, 61 (28), 8180-8189, 2022

  6. Allaparthi Venkata Satya Vithin, Ankur Vishnoi, and Rajshekhar Gannavarpu, Phase derivative estimation in digital holographic interferometry using a deep learning approach, Applied Optics, 61 (11), 3061-3069, 2022

  7. Anik Ghosh, Rishikesh Kulkarni and Rajshekhar Gannavarpu, Phase unwrapping algorithm using breadth-first-search and multi-level segmentation of phase quality interval in digital holography, Journal of Modern Optics, 69(16), 957-967, 2022

  8. Jagadesh Ramaiah, Ankur Vishnoi, and Rajshekhar Gannavarpu, Non-invasive surface profile measurement using a unitary transformation subspace approach in digital holography, Optics Continuum, 1 (4), 684-696, 2022

  9. Shikha Sharma, Rishikesh Kulkarni, Ankur Vishnoi and Rajshekhar Gannavarpu, Wrapped phase denoising using adaptive Kalman smoother algorithm, Journal of Modern Optics, 69 (15), 838-849, 2022

  10. Jagadesh Ramaiah and Rajshekhar Gannavarpu, Dynamic displacement measurement in digital holographic interferometry using eigenspace analysis, Applied Optics, 60 (33), 10468-10476, 2021

  11. Dhruvam Pandey, Jagadesh Ramaiah and Rajshekhar Gannavarpu, Fast measurement of phase and its derivatives in digital holographic interferometry using graphics processing unit assisted state space method, Optik, 248, 168172, 2021

  12. Shikha Sharma, Rishikesh Kulkarni, Sreeprasad Ajithaprasad and Rajshekhar Gannavarpu, Fringe pattern normalization algorithm using Kalman filter, Results in Optics, 5, 100152, 2021

  13. Jagadesh Ramaiah and Rajshekhar Gannavarpu, Non-invasive deformation metrology using subspace analysis in digital holographic interferometry, Measurement Science and Technology, 32 (12), 125201, 2021

  14. Ankur Vishnoi and Rajshekhar Gannavarpu, Single shot quantitative phase gradient estimation using Wigner-Ville distribution in digital holographic microscopy, Optics Continuum, 4 (9), 2452-2459, 2021 (Selected as Editor’s Pick)

  15. Ankur Vishnoi, Aditya Madipadaga, Sreeprasad Ajithaprasad and Rajshekhar Gannavarpu, Automated defect identification from carrier fringe patterns using Wigner–Ville distribution and a machine learning-based method, Applied Optics, 60 (15), 4391-4397, 2021

  16. Allaparthi Venkata Satya Vithin, Ankur Vishnoi and Rajshekhar Gannavarpu, Demodulation of noisy interferograms with rapid phase variations and amplitude fluctuations using a surrogate principle-based optimization method, Applied Optics, 60 (7), 1937-1942, 2021

  17. Allaparthi Venkata Satya Vithin, Issac Show, Sreeprasad Ajithaprasad and Rajshekhar Gannavarpu, Demodulating interferograms with non-uniform amplitude variations for precision non-contact optical profilometry, Optics and Lasers in Engineering, 134, 106292, 2020

  18. Sreeprasad Ajithaprasad, Jagadesh Ramaiah and Rajshekhar Gannavarpu, Dynamic noncontact surface profilometry using a fast eigenspace method in diffraction phase microscopy, Applied Optics, 59 (19), 5796-5802, 2020

  19. Jagadesh Ramaiah, Sreeprasad Ajithaprasad, Rajshekhar Gannavarpu and Dario Ambrosini, Fast and robust method for flow analysis using GPU assisted diffractive optical element based background oriented schlieren (BOS), Optics and Lasers in Engineering, 126, 105908, 2020

  20. Allaparthi Venkata Satya Vithin, Sreeprasad Ajithaprasad, and Gannavarpu Rajshekhar, Step phase reconstruction using an anisotropic total variation regularization method in a diffraction phase microscopy, Applied Optics, 58 (26), 7189-7194, 2019

  21. Jagadesh Ramaiah, Sreeprasad Ajithaprasad and Gannavarpu Rajshekhar, Graphics processing unit assisted diffraction phase microscopy for fast non-destructive metrology, Measurement Science and Technology, 30 (12), 125202, 2019

  22. Ankur Vishnoi, Sreeprasad Ajithaprasad and Gannavarpu Rajshekhar, Wigner–Ville distribution based diffraction phase microscopy for non-destructive testing, Journal of Modern Optics, 66 (16), 1644-1651, 2019

  23. Ankur Vishnoi and Gannavarpu Rajshekhar, Rapid deformation analysis in digital holographic interferometry using graphics processing unit accelerated Wigner–Ville distribution, Applied Optics, 58 (16), 4420-4424, 2019 (Selected as Editor’s Pick)

  24. Ankur Vishnoi, Jagadesh Ramaiah, and Gannavarpu Rajshekhar, Phase recovery method in digital holographic interferometry using high-resolution signal parameter estimation, Applied Optics, 58, 1485-1490, 2019

  25. Sreeprasad Ajithaprasad, Raviteja Velpula and Gannavarpu Rajshekhar, Defect detection using windowed Fourier spectrum analysis in diffraction phase microscopy, Journal of Physics Communications, 3, 025006, 2019

  26. Jagadesh Ramaiah and Gannavarpu Rajshekhar , Single shot multiple phase retrieval in digital holographic interferometry using subspace processing, Optics and Lasers in Engineering, 111, 201-205, 2018

  27. Gannavarpu Rajshekhar and Dario Ambrosini, Multi-scale approach for analyzing convective heat transfer flow in background-oriented Schlieren technique, Optics and Lasers in Engineering, 110, 415-419, 2018

  28. Sreeprasad Ajithaprasad and Gannavarpu Rajshekhar, Non-invasive precision metrology using diffraction phase microscopy and space-frequency method, Optics and Lasers in Engineering, 109, 17-22, 2018

  29. Jagadesh Ramaiah, Pramod Rastogi and Gannavarpu Rajshekhar, Demodulation of moire fringes in digital holographic interferometry using an extended Kalman filter, Applied Optics, 57, 1944-1949, 2018

  30. Lihong Ma, Gannavarpu Rajshekhar, Ru Wang, Basanta Bhaduri, Shamira Sridharan, Mustafa Mir, Arindam Chakraborty, Rajashekar Iyer, Supriya Prasanth, Larry Millet, Martha U Gillette, Gabriel Popescu, Phase correlation imaging of unlabeled cell dynamics, Nature Scientific Reports, 6, 32702, 2016

  31. Gannavarpu Rajshekhar, Basanta Bhaduri, Krishna Tangella and Gabriel Popescu, Spatiotemporal characterization of a fibrin clot using quantitative phase imaging, PLOS ONE, 9(11), e111381, 2014.

  32. Gannavarpu Rajshekhar, Basanta Bhaduri, C. Edwards, R. Zhou, L. L. Goddard and Gabriel Popescu, Nanoscale topography and spatial light modulator characterization using wide-field quantitative phase imaging, Optics Express, 22(3), 3432-3438, 2014.

  33. Gannavarpu Rajshekhar and Pramod Rastogi, Phase estimation using a state-space approach based method, Optics and Lasers in Engineering, 51(8), 1004-1007, 2013.

  34. Gannavarpu Rajshekhar and Pramod Rastogi, Fringe demodulation using the two-dimensional phase differencing operator, Optics Letters, 37(20), 4278-4280, 2012.

  35. Gannavarpu Rajshekhar and Pramod Rastogi, Multiple signal classification technique for phase estimation from a fringe pattern, Applied Optics, 51(24), 5869-5875, 2012.

  36. Gannavarpu Rajshekhar and Pramod Rastogi, Fringe analysis: Premise and perspectives, Optics and Lasers in Engineering, 50(8), iii-x, 2012.

  37. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Detection of defects from fringe patterns using a pseudo Wigner-Ville distribution based method, Optics and Lasers in Engineering, 50(8), 1059-1062, 2012.

  38. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Estimation of multiple phases from a single fringe pattern in digital holographic interferometry, Optics Express, 20(2), 1281-1291, 2012.

  39. Saisiva Gorthi, Gannavarpu Rajshekhar and Pramod Rastogi, Three dimensional shape measurement using high-order instantaneous moments based fringe projection method, Optics and Laser Technology, 43 (1), 40-44, 2011.

  40. Gannavarpu Rajshekhar and Pramod Rastogi, Application of complex-lag distributions for estimation of arbitrary order phase derivatives in digital holographic interferometry, Optics Letters, 36(19), 3738-3740, 2011.

  41. Gannavarpu Rajshekhar, Saisiva Gorthi, and Pramod Rastogi, Simultaneous measurement of in-plane and out-of-plane displacement derivatives using dual-wavelength digital holographic interferometry, Applied Optics, 50(34), H16-H21, 2011.

  42. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Simultaneous multidimensional deformation measurements using digital holographic moiré, Applied Optics, 50(21), 4189-4197, 2011.

  43. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Estimation of dynamically varying displacement derivatives using fringe projection technique, Applied Optics, 50(3), 282-286, 2011.

  44. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Estimation of displacement derivatives in digital holographic interferometry using a two-dimensional space-frequency distribution, Optics Express, 18(17), 18041-18046, 2010.

  45. Saisiva Gorthi, Gannavarpu Rajshekhar and Pramod Rastogi, Strain estimation in digital holographic interferometry using piecewise polynomial phase approximation based method, Optics Express, 18(2), 560-565, 2010.

  46. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Estimation of phase derivative using adaptive window spectrogram, Journal of Optical Society of America A, 27(1), 69-75, 2010.

  47. Saisiva Gorthi, Gannavarpu Rajshekhar and Pramod Rastogi, Investigation to realize a computationally efficient implementation of the high-order instantaneous-moments-based fringe analysis method, Optical Engineering, 49 (6), 065802-065802-4, 2010

  48. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Polynomial Wigner-Ville distribution based method for direct phase derivative estimation from optical fringes, Journal of Optics A: Pure and Applied Optics, 11(12), 125402, 2009.

  49. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Strain, curvature and twist measurements in digital holographic interferometry using pseudo Wigner-Ville distribution based method, Review of Scientific Instruments, 80, 093107, 2009.

  50. Gannavarpu Rajshekhar, Saisiva Gorthi and Pramod Rastogi, Adaptive window Wigner-Ville distribution based method to estimate phase derivative from optical fringes, Optics Letters, 34(20), 3151-3153, 2009.

Conferences

  1. Dhruvam Pandey and Rajshekhar Gannavarpu, “Fringe Pattern Defect Identification Using Kalman Filter and Machine Learning”, Digital Holography and Three-Dimensional Imaging, OSA Imaging and Applied Optics Congress, W2A.6, 2022

  2. Allaparthi Venkata Satya Vithin, Jagadesh Ramaiah, Dhruvam Pandey and Rajshekhar Gannavarpu, “Displacement Derivative Analysis Using Deep Learning in Digital Holographic Interferometry”, Digital Holography and Three-Dimensional Imaging, OSA Imaging and Applied Optics Congress, W2A.7, 2022

  3. Allaparthi Venkata Satya Vithin and Rajshekhar Gannavarpu, “Estimation of phase derivative with sharp variations in digital holography using total variational regularization”, Digital Holography and Three-Dimensional Imaging, OSA Imaging and Applied Optics Congress, JTh6A.33, 2021

  4. Allaparthi Venkata Satya Vithin and Rajshekhar Gannavarpu, “Robust method for fringe demodulation under rapid phase and amplitude fluctuations”, Digital Holography and Three-Dimensional Imaging, OSA Imaging and Applied Optics Congress, JTh6A.32, 2021

  5. Jagadesh Ramaiah and Rajshekhar Gannavarpu, “Defect localization in noisy fringe patterns using subspace method and naive Bayes classifier”, Digital Holography and Three-Dimensional Imaging, OSA Imaging and Applied Optics Congress, JTh6A.31, 2021

  6. Allaparthi Venkata Satya Vithin, Issac Show, Sreeprasad Ajithaprasad, and Gannavarapu Rajshekhar, “Demodulation of fringe patterns corrupted by non uniform intensity variations in dynamics studies”, Proc. SPIE 11552, Optical Metrology and Inspection for Industrial Applications VII, 115521Z, 2020

  7. Jagadesh Ramaiah and Rajshekhar Gannavarpu, “Dynamic fringe analysis using GPU assisted root-MUSIC method”, Proc. SPIE 11552, Optical Metrology and Inspection for Industrial Applications VII, 1155206, 2020

  8. Aditya Madipadaga and Rajshekhar Gannavarpu, “Investigation of temporally varying fringe pattern defects using machine learning for optical metrology”, Proc. SPIE 11552, Optical Metrology and Inspection for Industrial Applications VII, 115520L, 2020

  9. Ankur Vishnoi and Gannavarpu Rajshekhar, “Fast fringe analysis method using graphics processing unit acceleration for dynamic fault identification”, Proc. SPIE 11352, Optics and Photonics for Advanced Dimensional Metrology, 113520J, 2020

  10. Sreeprasad Ajithaprasad, Vigneshwar Rajendran and Gannavarpu Rajshekhar, ” A GPU assisted space frequency method for dynamic defect detection in optical metrology”, Proc. SPIE 11205, Seventh International Conference on Optical and Photonic Engineering (icOPEN 2019) Thailand, 1120526, 2019

  11. Sreeprasad Ajithaprasad, Jagadesh Ramaiah and Gannavarpu Rajshekhar, “Dynamic deformation analysis using diffraction phase microscopy and space-frequency analysis”, 4th edition of the IEEE Workshop on Recent Advances in Photonics (WRAP) 2019, Indian Institute of Technology (IIT), Guwahati, India

  12. Sreeprasad Ajithaprasad, Jagadesh Ramaiah and Gannavarpu Rajshekhar, “Non-contact optical surface profilometry using diffraction phase microscopy and subspace method”, International Conference on Optics and electro-optics (ICOL) 2019, Instruments Research and Development Establishment (IRDE), Dehradun, Uttarakhand, INDIA

  13. Ankur Vishnoi and Gannavarpu Rajshekhar, “High speed non-destructive testing method using digital holographic interferometry”, International Conference on Optics and electro-optics (ICOL) 2019, Instruments Research and Development Establishment (IRDE), Dehradun, Uttarakhand, INDIA

  14. Sreeprasad Ajithaprasad, Gannavarpu Rajshekhar, “Laser assisted defect detection using diffraction phase microscopy and space frequency analysis”, National Photonics Symposium 2019, International School of Photonics, Cochin, India

  15. Ankur Vishnoi, Jagadesh Ramaiah, Gannavarpu Rajshekhar, “Phase derivative estimation in digital holography interferometry using multiple signal classification method”, The International Conference on Fiber Optics and Photonics - PHOTONICS, IIT Delhi, 2018

  16. Jagadesh Ramaiah, Gannavarpu Rajshekhar, “Fringe analysis using extended Kalman filter and matrix enhancement techniques”, The International Conference on Fiber Optics and Photonics - PHOTONICS, IIT Delhi, 2018

  17. Sreeprasad Ajithaprasad, Gannavarpu Rajshekhar, “Nanoscale non-destructive measurement of surface profile using diffraction phase microscopy and windowed Fourier transform”, The International Conference on Fiber Optics and Photonics - PHOTONICS, IIT Delhi, 2018

  18. Lihong Ma, Rajshekhar Gannavarpu, Ru Wang, Basanta Bhaduri, Shamira Sridharan, Mustafa A Mir, Arindam Chakraborty, Supriya G Prasanth, Larry Millet, Martha U Gillette, Gabriel Popescu, “Phase correlation imaging (PCI) for cell dynamics investigation”, Proc. SPIE 9718, Quantitative Phase Imaging II, 97180P, USA , 2016.

  19. Dario Ambrosini and Rajshekhar Gannavarpu, “Quantitative schardin’s schlieren 2 in heat and mass transfer studies”, International Conference on Combined Digital Optical & Imaging Methods applied to Mechanical Engineering, Ascona, Switzerland, 2016

  20. Gannavarpu Rajshekhar, Basanta Bhaduri, Krishnarao Tangella, and Gabriel Popescu, “Three-dimensional fractal structure of a blood clot using quantitative phase imaging”, Digital Holography and Three-Dimensional Imaging, Seattle(USA), OSA , DM4B.4, 2014.

  21. Gannavarpu Rajshekhar, Basanta Bhaduri, Chris Edwards, Renjie Zhou, Lynford Goddard, and Gabriel Popescu, “Wide-field diffraction phase microscope for precision metrology”, Digital Holography and Three-Dimensional Imaging, Seattle(USA), OSA , DTh1B.2, 2014.

  22. Gannavarpu Rajshekhar and Pramod Rastogi, “Measuring phase derivatives in digital holographic interferometry”, Digital Holography and Three-Dimensional Imaging, Seattle(USA), OSA , DTh1B.1, 2014.

  23. Gannavarpu Rajshekhar, Sai Siva Gorthi, and Pramod Rastogi, “Comparative Analysis of Various Single-tone Frequency Estimation Techniques in High-order Instantaneous Moments Based Phase Estimation Method”, AIP Conference Proceedings, 1236, 355-358, 2010.

  24. Saisiva Gorthi, Gannavarpu Rajshekhar, and Pramod Rastogi, “Estimation of Phase in Fringe Projection Technique Using High-order Instantaneous Moments Based Method”, AIP Conference Proceedings, 1236, 359-362, 2010.

Book Chapter

  1. G. Rajshekhar, S.S. Gorthi, and P. Rastogi, “Local Polynomial Phase Modeling and Estimation”, Phase estimation in Optical Interferometry , CRC Press, 2014.

Contact

Dr. Gannavarpu Rajshekhar
ACES 325B
Department of Electrical Engineering
IIT Kanpur
Kanpur-208016, Uttar Pradesh, India
Email: gshekhar@iitk.ac.in
Phone: +91-512-259-6477