Dr. Shilpi Agarwal Profile

Dr. Shilpi Agarwal

at Jawaharlal Nehru Univ.

SPIE Involvement:

Author

Publications (12)

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 | 19 December 2022 Presentation + Paper

Measurement of temperature and temperature profile of nanoparticle additive liquid fuel by interferometry

Shilpi Agarwal

Proceedings Volume 12319, 123190B (2022) https://doi.org/10.1117/12.2644229

KEYWORDS: Nanoparticles, Combustion, Temperature metrology, Interferometry, Flame, Liquids, Diffraction gratings, Oxides, Refractive index, Oxygen

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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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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

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 | 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

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 | 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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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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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 | 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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Showing 5 of 12 publications

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