Prof. Kehar Singh Profile

Prof. Kehar Singh

Retired

SPIE Involvement:

Author

Publications (43)

Proceedings Article | 15 June 2015 Paper

Watermarking in gyrator domain using an asymmetric cryptosystem

Sunanda Vashisth, A. Yadav, Hukun Singh, Kehar Singh

Proceedings Volume 9654, 96542E (2015) https://doi.org/10.1117/12.2183394

KEYWORDS: Digital watermarking, Image encryption, Image restoration, Binary data, Gyrators, Optical image encryption, Image quality, Computer programming, Phase shift keying, Signal attenuation

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SPIE Journal Paper | 1 April 2011

Simultaneous encryption of a color and a gray-scale image using byte-level encoding based on single-channel double random-phase encoding architecture in fractional Fourier domain

Madhusudan Joshi, Kehar Singh

OE, Vol. 50, Issue 04, 047007, (April 2011) https://doi.org/10.1117/12.10.1117/1.3569688

KEYWORDS: Image encryption, Computer programming, RGB color model, Image visualization, Optical image encryption, Eye, Optical engineering, Fractional fourier transform, Visualization, Digital imaging

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SPIE Journal Paper | 1 September 2010

Holographic encryption system in the Fresnel domain with convergent random illumination

Pramod Kumar, Joby Joseph, Kehar Singh

OE, Vol. 49, Issue 09, 095803, (September 2010) https://doi.org/10.1117/12.10.1117/1.3488043

KEYWORDS: Wavefronts, Holography, Image encryption, Optical image encryption, Computer security, Wave propagation, Optical engineering, Numerical simulations, Image retrieval, Illumination engineering

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SPIE Journal Paper | 1 December 2008

Double random phase encryption with in-plane rotation of a modified Lohmann's second-type system in the anamorphic fractional Fourier domain

Pramod Kumar, Joby Joseph, Kehar Singh

OE, Vol. 47, Issue 12, 129801, (December 2008) https://doi.org/10.1117/12.10.1117/1.3054186

SPIE Journal Paper | 1 November 2008

Double random phase encryption with in-plane rotation of a modified Lohmann's second-type system in the anamorphic fractional Fourier domain

Pramod Kumar, Joby Joseph, Kehar Singh

OE, Vol. 47, Issue 11, 117001, (November 2008) https://doi.org/10.1117/12.10.1117/1.3006084

KEYWORDS: Image encryption, Cylindrical lenses, Fourier transforms, Image processing, Optical engineering, Spherical lenses, Computer security, Fractional fourier transform, Information security, Optical image encryption

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SPIE Journal Paper | 1 November 2008

Lensless complex data encoding for digital holographic whole information security

Anith Nelleri, Joby Joseph, Kehar Singh

OE, Vol. 47, Issue 11, 115801, (November 2008) https://doi.org/10.1117/12.10.1117/1.3028351

KEYWORDS: Digital holography, Holograms, Holography, Computer programming, Information security, Digital recording, Image encryption, Digital imaging, Optical engineering, Optical signal processing

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SPIE Journal Paper | 1 April 2007

Digital Fresnel field encryption for three-dimensional information security

Anith Nelleri, Joby Joseph, Kehar Singh

OE, Vol. 46, Issue 04, 045801, (April 2007) https://doi.org/10.1117/12.10.1117/1.2727377

KEYWORDS: Digital holography, Holograms, Computer programming, Charge-coupled devices, Holography, Wavefronts, 3D image reconstruction, Image encryption, Information security, Computer security

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Proceedings Article | 21 July 2006 Paper

Muller matrix approach for determination of optical rotation in chiral turbid media in backscattering geometry

S. Manhas, M. Swami, P. Buddhiwant, N. Ghosh, P. Gupta, K. Singh

Proceedings Volume 6163, 61630W (2006) https://doi.org/10.1117/12.697294

KEYWORDS: Backscatter, Polarization, Scattering, Glucose, Light scattering, Wave plates, Tissue optics, Molecules, Mie scattering, Spherical lenses

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Proceedings Article | 8 June 2005 Paper

Wavelet based three-dimensional object recognition using single off-axis digital Fresnel hologram

Anith Nelleri, Unnikrishnan Gopinathan, Joby Joseph, Kehar Singh

Proceedings Volume 5827, (2005) https://doi.org/10.1117/12.605085

KEYWORDS: Digital holography, Holograms, Object recognition, Wavelets, 3D image processing, Wavefronts, Charge-coupled devices, Image processing, 3D image reconstruction, Digital filtering

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SPIE Journal Paper | 1 May 2005

Image encryption by using fractional Fourier transform and jigsaw transform in image bit planes

Aloka Sinha, Kehar Singh

OE, Vol. 44, Issue 05, 057001, (May 2005) https://doi.org/10.1117/12.10.1117/1.1906240

KEYWORDS: Image encryption, Computer security, Fractional fourier transform, Image compression, Optical engineering, Digital imaging, Information security, Image transmission, Fourier transforms, Computer simulations

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SPIE Journal Paper | 1 December 2004

Fully phase encryption using digital holography

Naveen Nishchal, Joby Joseph, Kehar Singh

OE, Vol. 43, Issue 12, (December 2004) https://doi.org/10.1117/12.10.1117/1.1811085

KEYWORDS: Image encryption, Holograms, Digital holography, Fourier transforms, Digital recording, CCD cameras, Charge-coupled devices, Spatial light modulators, Holography, Phase contrast

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SPIE Journal Paper | 1 October 2004

Fully phase-based encryption using fractional order Fourier domain random phase encoding: error analysis

Naveen Nishchal, Joby Joseph, Kehar Singh

OE, Vol. 43, Issue 10, (October 2004) https://doi.org/10.1117/12.10.1117/1.1790503

KEYWORDS: Image encryption, Image restoration, Binary data, Image quality, Computer programming, Computer simulations, Error analysis, Signal to noise ratio, Image compression, Optical image encryption

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SPIE Journal Paper | 1 December 2003

Optical encryption using a localized fractional Fourier transform

Naveen Nishchal, G. Unnikrishnan, Joby Joseph, Kehar Singh

OE, Vol. 42, Issue 12, (December 2003) https://doi.org/10.1117/12.10.1117/1.1624850

KEYWORDS: Image segmentation, Image encryption, Fractional fourier transform, Computer security, Optical image encryption, Fourier transforms, Diffractive optical elements, Holography, Optical engineering, Computer simulations

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Proceedings Article | 19 November 2003 Paper

Neural networks applied to measurement of three-dimensional object shapes using phases recovered from Fourier transform profilometry and phase locked loops

Dinesh Ganotra, Joby Joseph, Kehar Singh

Proceedings Volume 4829, (2003) https://doi.org/10.1117/12.530079

KEYWORDS: Neural networks, Calibration, Fourier transforms, Photography, Photonics, Physics, 3D metrology, Projection systems, Optical calibration, Optical aberrations

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Proceedings Article | 19 November 2003 Paper

Modified geometry of ring-wedge detector for sampling Fourier transform of fingerprints for classification using neural networks

Dinesh Ganotra, Joby Joseph, Kehar Singh

Proceedings Volume 4829, (2003) https://doi.org/10.1117/12.525222

KEYWORDS: Sensors, Fourier transforms, Neural networks, Image resolution, Sensor performance, Optical signal processing, Photodetectors, Neurons, Photonics, Physics

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Proceedings Article | 19 November 2003 Paper

Optical encryption techniques for data security

Kehar Singh

Proceedings Volume 4829, (2003) https://doi.org/10.1117/12.524636

KEYWORDS: Image encryption, Computer security, Computer programming, Optical signal processing, Information security, Polarization, Holograms, Holography, 3D image reconstruction, Optical image encryption

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Proceedings Article | 23 October 2003 Paper

Fully phase encrypted memory using cascaded extended fractional Fourier transform

Naveen Nishchal, Joby Joseph, Kehar Singh

Proceedings Volume 5202, (2003) https://doi.org/10.1117/12.503966

KEYWORDS: Image encryption, Crystals, Phase contrast, Phase conjugation, Lithium niobate, Fractional fourier transform, Computer programming, Spatial frequencies, Spatial light modulators, Holograms

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SPIE Journal Paper | 1 June 2003

Fully phase encryption using fractional Fourier transform

Naveen Nishchal, Joby Joseph, Kehar Singh

OE, Vol. 42, Issue 06, (June 2003) https://doi.org/10.1117/12.10.1117/1.1570429

KEYWORDS: Image encryption, Phase contrast, Spatial light modulators, Computer programming, Phase shifts, Fractional fourier transform, Crystals, Fourier transforms, Sensors, Phase shift keying

Proceedings Article | 20 November 2002 Paper

Photorefractive optical processing for data security

Kehar Singh, G. Unnikrishnan, Naveen Nishchal

Proceedings Volume 4803, (2002) https://doi.org/10.1117/12.452711

KEYWORDS: Image encryption, Computer programming, Computer security, Holography, Digital holography, Crystals, Optical image encryption, Optical signal processing, Spatial light modulators, Data communications

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Proceedings Article | 16 September 2002 Paper

Fractional Fourier transform: applications in information optics

Kehar Singh, Naveen Nishchal

Proceedings Volume 4929, (2002) https://doi.org/10.1117/12.483221

KEYWORDS: Image encryption, Fourier transforms, Fractional fourier transform, Optical correlators, Optical signal processing, Computer programming, Wigner distribution functions, Optical filters, Optical pattern recognition, Filtering (signal processing)

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Proceedings Article | 25 September 2001 Paper

Cryptography using optoelectronic techniques

G. Unnikrishnan, Kehar Singh

Proceedings Volume 4417, (2001) https://doi.org/10.1117/12.441293

KEYWORDS: Image encryption, Computer programming, Computer security, Optical image encryption, Digital holography, Crystals, Spatial light modulators, Holography, Optoelectronics, Polarization

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SPIE Journal Paper | 1 June 2001

Out-of-plane vibration measurement by speckle photography using photorefractive BaTiO3 crystal

K. Dharmsaktu, Arvind Kumar, Kehar Singh

OE, Vol. 40, Issue 06, (June 2001) https://doi.org/10.1117/12.10.1117/1.1370556

KEYWORDS: Crystals, Speckle, Diffusers, Speckle pattern, Vibrometry, Photography, Laser crystals, Fringe analysis, Phase modulation, Interferometry

SPIE Journal Paper | 1 November 2000

Double random fractional Fourier domain encoding for optical security

G. Unnikrishnan, Kehar Singh

OE, Vol. 39, Issue 11, (November 2000) https://doi.org/10.1117/12.10.1117/1.1313498

KEYWORDS: Image encryption, Commercial off the shelf technology, Fractional fourier transform, Computer programming, Fourier transforms, Optical engineering, Transformers, Numerical simulations, Digital imaging, Optical image encryption

Proceedings Article | 19 July 1999 Paper

Wavelet-assisted generalized fringe-adjusted nonzero order joint transform correlator for noise immunity and pattern discrimination

Renu Tripathi, G. Pati, Kehar Singh

Proceedings Volume 3749, (1999) https://doi.org/10.1117/12.355017

KEYWORDS: Wavelets, Joint transforms, Optical correlators, Fourier transforms, Target detection, Signal detection, Signal processing, Computer simulations, Interference (communication), Image filtering

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Proceedings Article | 7 May 1999 Paper

Optical encryption system using a spatial light modulator

G. Unnikrishnan, Joby Joseph, Kehar Singh

Proceedings Volume 3740, (1999) https://doi.org/10.1117/12.347734

KEYWORDS: Image encryption, Spatial light modulators, Crystals, Computer programming, Optical image encryption, Fourier transforms, Phase conjugation, Charge-coupled devices, Data conversion, Transparency

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