Prof. Chandra Shakher Profile

Prof. Chandra Shakher

Director/Professor at Instrument Design and Development Ctr

SPIE Involvement:

Author

Publications (64)

Proceedings Article | 5 January 2023 Presentation + Paper

In-plane coplanarity measurement by Talbot interferometer

Shilpi Agarwal, Chandra Shakher

Proceedings Volume 12319, 123190U (2023) https://doi.org/10.1117/12.2644120

KEYWORDS: Interferometers, Optical gratings, Interferometry, Diffraction gratings, Optical benches, Interferograms, 3D metrology

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The monitoring and measurement of in-plane coplanarity is important in the production and assembly of smaller and more fine-pitched optical and mechanical systems. Owing to its features such as greater accuracy, resolution, instantaneous response and non-intrusive nature, interferometry is advantageous and extensively utilized in a broad spectrum of applications. Interferometers possess high resolution, long measurement range and fast response times. Infra-Red diffraction interferometer is broadly used for coplanarity measurement [1-2]. Recently grating interferometer has been also used for the coplanarity measurement [3]. Circular grating Talbot interferometry has been widely used in many metrological as well as microscopic applications [4-10]. The benefits of using circular gratings are that they are easy to align, and no prior knowledge is needed for the measuring direction [10]. In this paper, a fast and cost-effective 3D (x, y, z- axis) measurement system for in-plane coplanarity inspection of an optical table is proposed. Different from the line-scanning measurement of traditional laser-based systems, the proposed, circular grating Talbot interferometer system with fringe shift measurement can provide the 3D (x, y, z -axis) measurement of coplanarity. With the conventional practice of using the zero Talbot area, it is not possible to obtain fringes of the non-coplanar surfaces unless the Talbot distance is much greater than the distance between the surfaces. The Talbot area is employed to measure the deformation of the two non-coplanar surfaces simultaneously. But this approach has a critical limitation, and the optical setup will be extremely case-sensitive. In the proposed system, Talbot interferometric fringes are extracted from the background image using image processing operations of background normalization to reduce the unevenness in the background intensity and the morphological grayscale dilation operation to eliminate the grating lines [9-10]. In the extracted Talbot interferometric fringes of these interferograms, the intensity distribution profile is plotted along the center of the grating. The center of the shifted fringe in intensity distribution profile is obtained after averaging the position of fringe. The shift between the center of two gratings determines the coplanarity. The resolution of this method is limited by the grating pitch and the capabilities of the imaging equipment.

Proceedings Article | 8 December 2022 Paper

Volume phase holographic grating based digital holographic interferometer for temperature measurement of human hand skin

Vivek Rastogi, Varun Kumar, Satish Kumar Dubey, Gufran Sayeed Khan, Chandra Shakher

Proceedings Volume 12480, 1248006 (2022) https://doi.org/10.1117/12.2660156

KEYWORDS: Skin, Temperature metrology, Digital holography, Holography, Sensors, Holographic interferometry, Volume holography, Refractive index, Infrared radiation, Holographic interferometers

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SPIE Journal Paper | 2 December 2021

Digital holographic interferometry for the measurement of temperature distribution around textile conductive yarn embedded in heating garments

Pramod Sankara Pillai, Shilpi Agarwal, Bipin Kumar, Ramasamy Alagirusamy, Apurba Das, Chandra Shakher

OE, Vol. 60, Issue 12, 124104, (December 2021) https://doi.org/10.1117/12.10.1117/1.OE.60.12.124104

KEYWORDS: Temperature metrology, Digital holography, Copper, Holographic interferometry, Refractive index, Holograms, Resistance, Optical engineering, Metals, Sensors

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Proceedings Article | 20 June 2021 Presentation + Paper

Volume phase holographic grating based digital holographic interferometer for measurement of temperature distribution and temperature fluctuations in diffusion flames

Vivek Rastogi, Varun Kumar, Satish Dubey, Gufran Khan, Chandra Shakher

Proceedings Volume 11782, 117820K (2021) https://doi.org/10.1117/12.2592405

KEYWORDS: Temperature metrology, Digital holography, Holographic interferometry, Diffusion, Holography, Volume holography, Signal to noise ratio, Interferometry, Holographic interferometers, Speckle

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Proceedings Article | 21 August 2020 Presentation + Paper

A Taguchi based performance predictive optimization model to design broadband antireflector

Deblina Sabui, T. Yuvaraj, Vinod Mishra, Arpit Gupta, Gufran Khan, Chandra Shakher

Proceedings Volume 11483, 114830K (2020) https://doi.org/10.1117/12.2568538

KEYWORDS: Reflection, Antireflective coatings, Silicon, Short wave infrared radiation, Refractive index, Tolerancing, Optimization (mathematics), Systems modeling, Performance modeling

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Proceedings Article | 20 August 2020 Presentation + Paper

Novel volume holographic grating-based spectrum-splitting concentrator for hybrid solar system

T. P. Yuvaraj, Deblina Sabui, Vinod Mishra, Gufran Khan, Chandra Shakher

Proceedings Volume 11495, 114950P (2020) https://doi.org/10.1117/12.2568625

KEYWORDS: Diffraction gratings, Holography, Volume holography, Solar concentrators, Diffraction, Solar energy, Solar cells, Optical filters, Optical design

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SPIE Journal Paper | 10 June 2020

Investigation of temperature profile and temperature stability of micro diffusion flame under the influence of magnetic field by use of a holo-shear lens-based interferometer

Varun Kumar, Vivek Rastogi, Shilpi Agarwal, Chandra Shakher

OE, Vol. 59, Issue 06, 064107, (June 2020) https://doi.org/10.1117/12.10.1117/1.OE.59.6.064107

KEYWORDS: Magnetism, Diffusion, Temperature metrology, Interferometers, Combustion, Refractive index, Optical engineering, Fringe analysis, Wavefronts, Photography

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Proceedings Article | 18 November 2019 Paper

Visual and quantitative investigation on heat flow performance from heat sinks using digital holographic interferometer

Varun Kumar, Chandra Shakher

Proceedings Volume 11188, 111881C (2019) https://doi.org/10.1117/12.2537516

KEYWORDS: Digital holography, Visualization, Holographic interferometry, Thermal effects, Avionic systems, Electronic components, Microelectromechanical systems, Holograms, Convection, Cooling systems

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Proceedings Article | 18 November 2019 Paper

Microscopic urinalysis by digital holographic microscopy

Vivek Rastogi, Shilpi Agarwal, Satish Kumar Dubey, Gufran Sayeed Khan, Chandra Shakher

Proceedings Volume 11188, 1118818 (2019) https://doi.org/10.1117/12.2537315

KEYWORDS: Digital holography, Holography, Microscopy, Crystals, Blood, Diagnostics, Chemical elements, Bacteria, Imaging systems, Glasses

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Proceedings Article | 18 November 2019 Paper

Holographic optical element based digital holographic interferometer for label-free imaging of staphylococcus aureus bacteria

Vivek Rastogi, Shilpi Agarwal, Rahul Gadkari, Chandra Shakher

Proceedings Volume 11188, 111881U (2019) https://doi.org/10.1117/12.2537317

KEYWORDS: Holographic optical elements, Bacteria, Digital holography, Holographic interferometers, Imaging systems, Signal to noise ratio, Pathogens, Oxygen, Metals, Holographic interferometry

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Proceedings Article | 18 November 2019 Paper

Holo-shear lens based interferometer for measurement of temperature distribution and fluctuation of temperature in micro flame

Varun Kumar, Vivek Rastogi, Shilpi Agarwal, Chandra Shakher

Proceedings Volume 11188, 111881F (2019) https://doi.org/10.1117/12.2537321

KEYWORDS: Temperature metrology, Interferometers, Spherical lenses, Refractive index, Combustion, Holograms, Wavefronts, Fringe analysis

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Proceedings Article | 21 June 2019 Paper

High resolution measurement of freeform wavefront by using self-imaging based sensor

Lalit MohanPant, K. Pant, Dali Burada, A. Ghosh, Gufran Khan, Chandra Shakher

Proceedings Volume 11056, 1105647 (2019) https://doi.org/10.1117/12.2525961

KEYWORDS: Wavefronts, Sensors, Collimation, Error analysis, Spatial resolution, Freeform optics, Metrology, Wavefront sensors, Algorithm development, Optical design

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Proceedings Article | 21 June 2019 Paper

Intrinsic surface feature based subaperture stitching of freeform wavefront

Kamal Pant, Dali Burada, Vinod Mishra, L. Pant, Amitava Ghosh, Gufran Khan, Stefan Sinzinger, Chandra Shakher

Proceedings Volume 11057, 1105708 (2019) https://doi.org/10.1117/12.2526037

KEYWORDS: Wavefronts, Image registration, Photovoltaics, Metrology, Data integration, Manufacturing, Phase measurement, Error analysis, Sensors, Freeform optics

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Proceedings Article | 23 April 2019 Presentation + Paper

Digital holographic interferometric in-vitro imaging of Escherichia coli (E. coli) bacteria

Vivek Rastogi, Rahul Gadkari, Shilpi Agarwal, Satish Dubey, Chandra Shakher

Proceedings Volume 11030, 1103011 (2019) https://doi.org/10.1117/12.2520881

KEYWORDS: Bacteria, Digital holography, Holograms, Holographic interferometry, Microscopy, Fourier transforms, Imaging systems

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Proceedings Article | 23 April 2019 Presentation + Paper

Measurement of temperature and temperature fluctuations in wick stabilized micro flame using digital holographic interferometry

Shilpi Agarwal, Vivek Rastogi, Varun Kumar, Satish Dubey, Chandra Shakher

Proceedings Volume 11030, 1103012 (2019) https://doi.org/10.1117/12.2520885

KEYWORDS: Temperature metrology, Digital holography, Diffusion, Holograms, Refractive index, Combustion, Holographic interferometry, Sensors, Spherical lenses, Convection

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SPIE Journal Paper | 24 September 2018 Open Access

Measurement of initial displacement of canine and molar in human maxilla under different canine retraction methods using digital holographic interferometry

Manoj Kumar, Anshu Singh Birhman, Sridhar Kannan, Chandra Shakher

OE, Vol. 57, Issue 09, 094106, (September 2018) https://doi.org/10.1117/12.10.1117/1.OE.57.9.094106

KEYWORDS: Digital holography, Teeth, Holograms, Holographic interferometry, Digital recording, 3D image reconstruction, Optical engineering, Signal to noise ratio, Skull, Finite element methods

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Proceedings Article | 7 September 2018 Paper

Deformation measurements in cortical bone-miniscrew interface in human maxilla by using digital speckle pattern interferometry

Manoj Kumar, Rupali Agarwal, Ravi Bhutani, Chandra Shakher

Proceedings Volume 10834, 1083412 (2018) https://doi.org/10.1117/12.2317714

KEYWORDS: Bone, Interfaces, Fringe analysis, Interferometry, Speckle pattern, Beam splitters, Photography, Skull, Teeth, Finite element methods

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Proceedings Article | 7 September 2018 Paper

Holographic optical element based digital speckle pattern shearing interferometer

Manoj Kumar, Chandra Shakher

Proceedings Volume 10834, 1083414 (2018) https://doi.org/10.1117/12.2318342

KEYWORDS: Magnetism, Glasses, Holographic optical elements, Wavefronts, Fringe analysis, Temperature metrology, Speckle pattern, Speckle, Refractive index, Digital holography

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SPIE Journal Paper | 23 May 2018

Low-frequency in-plane vibration monitoring/measurement using circular grating Talbot interferometer

Shilpi Agarwal, Chandra Shakher

OE, Vol. 57, Issue 05, 054112, (May 2018) https://doi.org/10.1117/12.10.1117/1.OE.57.5.054112

KEYWORDS: Interferometry, Fringe analysis, Diffraction gratings, Interferometers, Image processing, Phase measurement, Oscilloscopes, Optical engineering, Vibrometry, Collimation

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SPIE Journal Paper | 13 October 2017 Open Access

Analysis of red blood cell parameters by Talbot-projected fringes

Shilpi Agarwal, Varun Kumar, Chandra Shakher

JBO, Vol. 22, Issue 10, 106009, (October 2017) https://doi.org/10.1117/12.10.1117/1.JBO.22.10.106009

KEYWORDS: Blood, Refractive index, 3D image processing, Phase measurement, Microscopy, CCD cameras, Microscopes, Imaging systems, Image resolution, Fringe analysis

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Proceedings Article | 22 August 2017 Paper

Phase contrast imaging of red blood cells using digital holographic interferometric microscope

Varun Kumar, Gufran Khan, Chandra Shakher

Proceedings Volume 10453, 104532T (2017) https://doi.org/10.1117/12.2276335

KEYWORDS: Digital holography, Holographic interferometry, Phase contrast, Microscopes, Blood, Phase shifting, Phase compensation, 3D image reconstruction, Holograms, Interferometry

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SPIE Journal Paper | 22 August 2017

Experimental investigations on characterization of freeform wavefront using Shack–Hartmann sensor

Dali Burada, Kamal Pant, Mohamed Bichra, Gufran Khan, Stefan Sinzinger, Chandra Shakher

OE, Vol. 56, Issue 08, 084107, (August 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.8.084107

KEYWORDS: Wavefronts, Photovoltaics, Sensors, Aspheric lenses, Diffractive optical elements, Freeform optics, Interferometry, Optical engineering, Metrology, Error analysis

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Proceedings Article | 22 August 2017 Paper

Onion cell imaging by using Talbot/self-imaging effect

Shilpi Agarwal, Varun Kumar, Chandra Shakher

Proceedings Volume 10453, 104532X (2017) https://doi.org/10.1117/12.2276348

KEYWORDS: Diffraction gratings, 3D image processing, Fourier transforms, Optical microscopy, Microscopy, Interferometry, Medical research, Live cell imaging, Phase contrast, Ultraviolet radiation

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Proceedings Article | 26 June 2017 Paper

Development of metrology for freeform optics in reflection mode

Dali Burada, Kamal Pant, Vinod Mishra, Mohamed Bichra, Gufran Khan, Stefan Sinzinger, Chandra Shakher

Proceedings Volume 10329, 103291K (2017) https://doi.org/10.1117/12.2270284

KEYWORDS: Metrology, Optics manufacturing, Wavefront sensors, Freeform optics, Sensors, Optical testing, Fabrication, Manufacturing, 3D metrology, Projection systems, Wavefronts, Beam splitters, Reflection, Photovoltaics

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SPIE Journal Paper | 24 January 2017

Measurement of temperature and temperature profile of wick stabilized micro diffusion flame under the effect of magnetic field using digital speckle pattern interferometry

Pranav Kumar Pandey, Manoj Kumar, Varun Kumar, Chandra Shakher

OE, Vol. 56, Issue 01, 014106, (January 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.1.014106

KEYWORDS: Magnetism, Temperature metrology, Fringe analysis, Diffusion, Refractive index, Interferometry, Digital filtering, Combustion, Speckle pattern, Speckle

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SPIE Journal Paper | 5 May 2016

Measurement of strain distribution in cortical bone around miniscrew implants used for orthodontic anchorage using digital speckle pattern interferometry

Manoj Kumar, Rupali Agarwal, Ravi Bhutani, Chandra Shakher

OE, Vol. 55, Issue 05, 054101, (May 2016) https://doi.org/10.1117/12.10.1117/1.OE.55.5.054101

KEYWORDS: Bone, Fringe analysis, Interferometry, Speckle pattern, Titanium, Speckle, Optical engineering, Nickel, Skull, Finite element methods

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Proceedings Article | 26 April 2016 Paper

Measurement of hygroscopic strain in deodar wood during convective drying using lensless Fourier transform digial holography

Manoj Kumar, Chandra Shakher

Proceedings Volume 9890, 989007 (2016) https://doi.org/10.1117/12.2227464

KEYWORDS: Holography, Holographic interferometry, Fourier transforms, Interferometry, Absorption, Holograms, Digital filtering, Digital recording, Beam splitters, Wavefronts

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Proceedings Article | 24 August 2015 Paper

Measurement of elastic and thermal properties of composite materials using digital speckle pattern interferometry

Manoj Kumar, Gufran Khan, Chandra Shakher

Proceedings Volume 9660, 966011 (2015) https://doi.org/10.1117/12.2196390

KEYWORDS: Composites, Speckle, Interferometry, Speckle pattern, Fringe analysis, Fiber reinforced polymers, Beam splitters, Digital holography, Phase shifts, Infrared imaging

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Proceedings Article | 24 August 2015 Paper

Analysis of alcohol-water diffusion process using digital holographic interferometry

Shilpi Agarwal, Manoj Kumar, Varun Kumar, Chandra Shakher

Proceedings Volume 9660, 96600S (2015) https://doi.org/10.1117/12.2196422

KEYWORDS: Diffusion, Digital holography, Holograms, Fourier transforms, Holographic interferometry, 3D image reconstruction, Refractive index, Beam splitters, Spherical lenses, Diffusers

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Proceedings Article | 24 August 2015 Paper

Temperature measurement of axi- symmetric butane diffusion flame under the influence of upward decreasing gradient magnetic field using digital holographic interferometry

Varun Kumar, Manoj Kumar, Chandra Shakher

Proceedings Volume 9660, 96600I (2015) https://doi.org/10.1117/12.2196396

KEYWORDS: Magnetism, Digital holography, Holograms, Temperature metrology, Refractive index, Diffusion, Holographic interferometry, Oxygen, Digital recording, Combustion

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SPIE Journal Paper | 7 August 2015

Measurement of temperature and temperature profile of candle flame using holo-shear lens and Fourier fringe analysis technique

Varun Kumar, Chandra Shakher

OE, Vol. 54, Issue 08, 084105, (August 2015) https://doi.org/10.1117/12.10.1117/1.OE.54.8.084105

KEYWORDS: Temperature metrology, Fringe analysis, Refractive index, Interferometry, Interferometers, Wavefronts, Fourier transforms, Speckle, Phase measurement, Holography

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Proceedings Article | 17 December 2013 Paper

Measurement of temperature and temperature distribution in diffusion flames using digital speckle pattern interferometry

Manoj Kumar, Varun Kumar, Chandra Shakher

Proceedings Volume 9066, 90660Y (2013) https://doi.org/10.1117/12.2047634

KEYWORDS: Temperature metrology, Speckle, Diffusion, Refractive index, Speckle pattern, Fringe analysis, Interferometry, Combustion, CMOS sensors, Beam splitters

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Proceedings Article | 27 May 2011 Paper

Application of wavelet transform and image morphology in processing vibration speckle interferogram for automatic analysis

Rajesh Kumar, Dibya Prakash Jena, Chandra Shakher

Proceedings Volume 8082, 80821Y (2011) https://doi.org/10.1117/12.889449

KEYWORDS: Speckle, Image filtering, Wavelets, Signal to noise ratio, Image processing, Denoising, Wavelet transforms, Digital filtering, Linear filtering, Smoothing

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SPIE Journal Paper | 1 January 2011

Clustering of optically trapped large diameter plasmonic gold nanoparticles by laser beam of hybrid-TEM₁₁* mode

Ranjeet Kumar, Dalip Mehta, Chandra Shakher

JNP, Vol. 5, Issue 01, 053511, (January 2011) https://doi.org/10.1117/12.10.1117/1.3600647

KEYWORDS: Scattering, Absorption, Particles, Laser scattering, Plasmons, Gold, Nanoparticles, Transmission electron microscopy, Temperature metrology, Light scattering

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Proceedings Article | 25 November 2010 Paper

Interferometry for topographical diagnostics of RBCs in optical tweezers

Ranjeet Kumar, Sarita Saraswati, Chandra Shakher, Dalip Mehta

Proceedings Volume 7376, 73760G (2010) https://doi.org/10.1117/12.878959

KEYWORDS: Optical tweezers, Refractive index, Interferometry, Fourier transforms, Reflection, Beam splitters, Wavefronts, Michelson interferometers, Mirrors, Tissues

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Proceedings Article | 3 October 2008 Paper

Measurement of temperature field in steady laminar free convection flow using digital holography

Chandra Shakher, Md. Mosarraf Hossain, Dalip Singh Mehta, Gyanendra Sheoran

Proceedings Volume 7155, 71551X (2008) https://doi.org/10.1117/12.814570

KEYWORDS: Digital holography, Temperature metrology, Convection, Holograms, Interferometry, Fourier transforms, Speckle, Holographic interferometry, Holography, 3D image reconstruction

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Proceedings Article | 3 October 2008 Paper

Full-field swept-source optical coherence tomography with Gaussian spectral shaping

Satish Kumar Dubey, Gyanendra Sheoran, Tulsi Anna, Arun Anand, Dalip Singh Mehta, Chandra Shakher

Proceedings Volume 7155, 71551F (2008) https://doi.org/10.1117/12.814551

KEYWORDS: Optical coherence tomography, Signal detection, Glasses, Sensors, Light sources, Refractive index, Charge-coupled devices, Optical filters, Superluminescent diodes, Tunable filters

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Proceedings Article | 3 October 2008 Paper

Application of plate vibration and DSPI in evaluation of elastic modulus

Rajesh Kumar, Chandra Shakher

Proceedings Volume 7155, 71550U (2008) https://doi.org/10.1117/12.814530

KEYWORDS: Speckle, Finite element methods, Aluminum, Vibrometry, Speckle pattern, Interferometry, CCD cameras, Beam splitters, Thin films, Nondestructive evaluation

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SPIE Journal Paper | 1 October 2006

Refractive index determination: an application of lensless Fourier digital holography

Mosarraf Hossain, Dalip Mehta, Chandra Shakher

OE, Vol. 45, Issue 10, 106203, (October 2006) https://doi.org/10.1117/12.10.1117/1.2358686

KEYWORDS: Digital holography, Refractive index, Holograms, Water, Liquids, Holography, 3D image reconstruction, Holographic interferometry, Reconstruction algorithms, Digital recording

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Proceedings Article | 14 August 2006 Paper

Determination of refractive index by digital holography

Md. Mosarraf Hossain, Dalip Singh Mehta, Chandra Shakher

Proceedings Volume 6293, 62930N (2006) https://doi.org/10.1117/12.680547

KEYWORDS: Digital holography, Refractive index, Holograms, Water, Liquids, Holographic interferometry, Reconstruction algorithms, 3D image reconstruction, Digital recording, Holography

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Proceedings Article | 18 August 2005 Paper

A new approach of surface roughness measurement using optical method and image processing

K. Chaudhary, R. Singhal, Shashi Singh, Chandera Shakher

Proceedings Volume 5879, 587914 (2005) https://doi.org/10.1117/12.620277

KEYWORDS: Surface roughness, 3D metrology, 3D image processing, CCD cameras, Image processing, Optical testing, Imaging systems, Surface finishing, Image acquisition, Cameras

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SPIE Journal Paper | 1 August 2005

Two-wavelength lateral shearing interferometry

Dalip Mehta, Priti Singh, Mohd Faridi, Saba Mirza, Chandra Shakher

OE, Vol. 44, Issue 08, 085603, (August 2005) https://doi.org/10.1117/12.10.1117/1.2012498

KEYWORDS: Interferometry, Phase measurement, Collimation, Optical components, Fringe analysis, Shearing interferometers, Wavefronts, Fourier transforms, Optical engineering, Superposition

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Proceedings Article | 13 June 2005 Paper

Profiling of gas turbine blade using phase shifting Talbot interferometric technique

Chandra Shakher, D. Mehta, Saba Mirza, Priti Singh

Proceedings Volume 5856, (2005) https://doi.org/10.1117/12.612471

KEYWORDS: Interferometry, Phase shifting, Fringe analysis, Image filtering, Profiling, Phase interferometry, Digital holography, Projection systems, Phase shift keying, Photography

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SPIE Journal Paper | 1 June 2005

Distance measurement with extended range using lateral shearing interferometry and Fourier transform fringe analysis

Dalip Mehta, Priti Singh, Mohd Faridi, Saba Mirza, Chandra Shakher

OE, Vol. 44, Issue 06, 063602, (June 2005) https://doi.org/10.1117/12.10.1117/1.1926127

KEYWORDS: Distance measurement, Fringe analysis, Wavefronts, Fourier transforms, Interferometry, Optical engineering, Optical filters, Sensors, Mirrors, Solids

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SPIE Journal Paper | 1 April 2005

Study of various preprocessing schemes and wavelet filters for speckle noise reduction in digital speckle pattern interferometric fringes

Saba Mirza, Rajesh Kumar, Chandra Shakher

OE, Vol. 44, Issue 04, 045603, (April 2005) https://doi.org/10.1117/12.10.1117/1.1886749

KEYWORDS: Speckle, Wavelets, Signal to noise ratio, Linear filtering, Fringe analysis, Image filtering, Digital filtering, Speckle pattern, Interferometry, Optical filters

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SPIE Journal Paper | 1 January 2005

Surface profiling using phase shifting Talbot interferometric technique

Saba Mirza, Chandra Shakher

OE, Vol. 44, Issue 01, 013601, (January 2005) https://doi.org/10.1117/12.10.1117/1.1827608

KEYWORDS: Interferometry, Phase shifts, Projection systems, Fringe analysis, Profiling, Phase shifting, Optical engineering, Optical filters, Phase interferometry, Interferometers

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Proceedings Article | 2 August 2004 Paper

Study of mode shapes and measurement of vibrations in square plates using DSPI and wavelet transform

Chandra Shakher, Saba Mirza, Rajesh Kumar

Proceedings Volume 5532, (2004) https://doi.org/10.1117/12.560375

KEYWORDS: Speckle, Digital filtering, Wavelets, Signal to noise ratio, Speckle pattern, Fringe analysis, Wavelet transforms, Interferometry, Linear filtering, Video

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Proceedings Article | 2 August 2004 Paper

Three-dimensional range sensing and surface profilometry using lateral shearing interferometry

Dalip Mehta, Priti Singh, Mohd Faridi, Saba Mirza, Chandra Shakher

Proceedings Volume 5532, (2004) https://doi.org/10.1117/12.560383

KEYWORDS: Interferometry, Fringe analysis, Distance measurement, Collimation, Wavefronts, Fourier transforms, Sensors, Spatial frequencies, Profilometers, Superposition

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Proceedings Article | 2 August 2004 Paper

Application of digital speckle pattern interferometry in measurement of large deformation

Rajesh Kumar, Vikas Rathi, Saba Mirza, Chandra Shakher

Proceedings Volume 5532, (2004) https://doi.org/10.1117/12.559560

KEYWORDS: Digital filtering, Speckle, Wavelets, Fringe analysis, Signal to noise ratio, Speckle pattern, Interferometry, Electronic filtering, Image filtering, Beam splitters

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Proceedings Article | 2 August 2004 Paper

Surface profiling of turbine blade using phase-shifting Talbot interferometric technique

Saba Mirza, Chandra Shakher

Proceedings Volume 5532, (2004) https://doi.org/10.1117/12.560385

KEYWORDS: Interferometry, Phase shifting, Fringe analysis, Profiling, Phase shifts, Interferometers, Image filtering, Digital image processing, Collimation, Phase shift keying

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SPIE Journal Paper | 1 February 2004

Measurement of temperature of an axisymmetric flame using shearing interferometry and Fourier fringe analysis technique

Priti Singh, Mohd Faridi, Chandra Shakher

OE, Vol. 43, Issue 02, (February 2004) https://doi.org/10.1117/12.10.1117/1.1635370

KEYWORDS: Temperature metrology, Interferometry, Fringe analysis, Fourier transforms, Wavefronts, Photography, Refractive index, Speckle, Phase measurement, Collimation

SPIE Journal Paper | 1 January 2003

Measurement of the temperature of a gaseous flame using a shearing plate

Priti Singh, Chandra Shakher

OE, Vol. 42, Issue 01, (January 2003) https://doi.org/10.1117/12.10.1117/1.1522727

KEYWORDS: Temperature metrology, Interferometry, Fringe analysis, Water, Refractive index, Wavefronts, Photography, Shearing interferometers, Holographic interferometry, Collimation

SPIE Journal Paper | 1 January 2003

Measurements of the temperature profile of a two-dimensional slot burner using a Lau phase interferometer with linear gratings

Madhuri Thakur, S. Angra, Chandra Shakher

OE, Vol. 42, Issue 01, (January 2003) https://doi.org/10.1117/12.10.1117/1.1523054

KEYWORDS: Temperature metrology, Phase interferometry, Interferometers, Fringe analysis, Refractive index, Water, Refraction, Interferometry, Diffraction gratings, Mouth

Proceedings Article | 16 September 2002 Paper

Application of wavelet transform in characterization of fabric texture

Chandra Shakher, S. Istiaque, Shashi Singh

Proceedings Volume 4929, (2002) https://doi.org/10.1117/12.483207

KEYWORDS: Wavelets, Wavelet transforms, Image processing, Linear filtering, Image segmentation, Image acquisition, Information visualization, Manufacturing, Defect detection, Image classification

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Proceedings Article | 9 September 2002 Paper

Measurement of out-of-plane vibrations by processing digital speckle pattern interferometry fringes using wavelet transform

Chandra Shakher, Rajesh Kumar

Proceedings Volume 4920, (2002) https://doi.org/10.1117/12.481964

KEYWORDS: Wavelets, Fringe analysis, Digital filtering, Speckle, Signal to noise ratio, Speckle pattern, Interferometry, Image filtering, Optical filters, Wavelet transforms

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Proceedings Article | 30 August 2002 Paper

Volume holographic lenses and their applications in white light imaging and concentration of solar energy

Chandra Shakher, Rajpal Sirohi

Proceedings Volume 4924, (2002) https://doi.org/10.1117/12.481507

KEYWORDS: Holograms, Holography, Lenses, Diffraction, Solar cells, Volume holography, Solar energy, Modulation, Refractive index, Photovoltaics

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SPIE Journal Paper | 1 January 2002

Application of wavelet filtering for vibration analysis using digital speckle pattern interferometery

Chandra Shakher, Rajesh Kumar, Shashi Singh, Saba Kazmi

OE, Vol. 41, Issue 01, (January 2002) https://doi.org/10.1117/12.10.1117/1.1420192

KEYWORDS: Wavelets, Digital filtering, Image filtering, Fringe analysis, Speckle pattern, Linear filtering, Optical filters, Vibrometry, Speckle, Digital holography

Proceedings Article | 8 May 2001 Paper

Lau phase interferometer for the measurement of the temperature and temperature profile of a gaseous flame

Chandra Shakher, Madhuri Thakur

Proceedings Volume 4416, (2001) https://doi.org/10.1117/12.427058

KEYWORDS: Temperature metrology, Phase interferometry, Interferometers, Diffraction gratings, Light sources, Phase measurement, Interferometry, Refractive index, Superposition, Photography

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Proceedings Article | 8 May 2001 Paper

Enhancement of contrast in digital speckle pattern interferometry fringes using wavelet transform

Chandra Shakher, Rajesh Kumar, Shashi Singh, Saba Kazmi

Proceedings Volume 4416, (2001) https://doi.org/10.1117/12.427020

KEYWORDS: Image filtering, Digital filtering, Wavelets, Speckle, Fringe analysis, Speckle pattern, Linear filtering, Image processing, Interferometry, Electronic filtering

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Proceedings Article | 6 September 1999 Paper

Testing of off-axis parabola by holo-shear lens

Chandra Shakher, K. Matsuda, Koji Tenjimbayashi

Proceedings Volume 3739, (1999) https://doi.org/10.1117/12.360164

KEYWORDS: Interferometers, Water, Holograms, Electroluminescence, Holography, Diffraction, Shearing interferometers, Zone plates, Interferometry, Wavefronts

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Proceedings Article | 19 July 1999 Paper

Temperature profile/fluctuations of a two-dimensional slot burner using laser speckle photography

Chandra Shakher, Ruchi Vats, S. Angra

Proceedings Volume 3749, (1999) https://doi.org/10.1117/12.354992

KEYWORDS: Photography, Speckle, Temperature metrology, Diffraction, Helium neon lasers, Diffusers, Speckle pattern, Interferometry, Laser interferometry, Microscopes

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Proceedings Article | 7 May 1999 Paper

Optoelectronic interferometric vibration sensor

Chandra Shakher, A. Vyas, V. Rawat

Proceedings Volume 3740, (1999) https://doi.org/10.1117/12.347776

KEYWORDS: Sensors, Signal processing, Signal detection, Interferometry, Optoelectronics, Interferometers, Mirrors, Amplifiers, Photodetectors, Linear filtering

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SPIE Journal Paper | 1 August 1994

Measurement of the temperature profile of an atomic absorption spectrophotometer burner using a Talbot interferometer with circular gratings

Chandra Shakher, A. Pramila Daniel, S. Angra

OE, Vol. 33, Issue 08, (August 1994) https://doi.org/10.1117/12.10.1117/12.173575

KEYWORDS: Temperature metrology, Absorption, Spectrophotometry, Photography, Interferometers, Interferometry, Diffraction gratings, Refraction, Fringe analysis, Deflectometry

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SPIE Journal Paper | 1 June 1994

Temperature profile measurement of axisymmetric gaseous flames using speckle photography, speckle shearing interferometry, and Talbot interferometry

Chandra Shakher, A. Pramila Daniel, Anil Nirala

OE, Vol. 33, Issue 06, (June 1994) https://doi.org/10.1117/12.10.1117/12.168849

KEYWORDS: Speckle, Interferometry, Photography, Temperature metrology, Diffusers, Refraction, Interferometers, Moire patterns, Refractive index, Data acquisition

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Showing 5 of 64 publications

Conference Committee Involvement (1)

Interferometry XII: Applications

4 August 2004 | Denver, Colorado, United States

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