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Pramod Rastogi

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Publications associées (112)

Multiple signal classification technique for phase estimation from a fringe pattern

Pramod Rastogi, Rajshekhar Gannavarpu

The paper introduces a multiple signal classification technique based method for fringe analysis. In the proposed method, the phase of a fringe pattern is locally approximated as a polynomial. The polynomial phase signal is then transformed to obtain signa ...

Optical Society of America2012

Role of data processing in measuring temperature gradients with DOE Schardin's schlieren #2

Pramod Rastogi, Sai Siva Gorthi

Flows having a variable fluid density can be visualized with optical methods. Recently, a background distortion technique, which can be considered a type of Schardin's schlieren #2, was proposed to study the refractive index variation in fluid and hence to ...

Elsevier2012

Estimation of multiple phases from a single fringe pattern in digital holographic interferometry

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

Simultaneous measurement of multidimensional displacements using digital holographic interferometry involves multi-directional illumination of the deformed object and requires the reliable estimation of the resulting multiple interference phase distributio ...

Optical Society of America2012

Fringe analysis: Premise and perspectives

Pramod Rastogi, Rajshekhar Gannavarpu

Elsevier2012

Fringe demodulation using the two-dimensional phase differencing operator

Pramod Rastogi, Rajshekhar Gannavarpu

The Letter proposes a method for phase estimation from a fringe pattern. The proposed method relies on a parametric approach where the phase is locally approximated as a two-dimensional (2D) polynomial, with the ensuing polynomial coefficients as the respe ...

Optical Society of America2012

Detection of defects from fringe patterns using a pseudo-Wigner-Ville distribution based method

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

The paper presents a method to identify defects from fringe patterns. In the proposed method, the phase derivatives are computed from a fringe pattern using the two-dimensional Pseudo-Wigner–Ville distribution. Since the phase derivative varies rapidly in ...

Elsevier2012

Simultaneous multidimensional deformation measurements using digital holographic moiré

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

This paper proposes an elegant technique for the simultaneous measurement of in-plane and out-of-plane displacements of a deformed object in digital holographic interferometry. The measurement relies on simultaneously illuminating the object from multiple ...

Optical Society of America2011

Correcting spherical aberrations induced by an unknown medium through determination of its refractive index and thickness

Pramod Rastogi, Daniel Iwaniuk

In imaging and focusing applications, spherical aberration induces axial broadening of the point spread function (PSF). A transparent medium between lens and object of interest induces spherical aberration. We propose a method that first obtains both the p ...

Optical Society of America2011

Estimation of dynamically varying displacement derivatives using fringe projection technique

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

This paper presents a pseudo Wigner–Ville-distribution-based method in fringe projection for analyzing temporal behavior of the displacement derivative for a continuously deformed object. In the proposed method, a computer generated fringe pattern is proje ...

Optical Society of America2011

Three dimensional shape measurement using high-order instantaneous moments based fringe projection method

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

Fringe projection techniques are popular tools for three-dimensional shape measurement in optical metrology. In these techniques, the information about the shape or the surface profile of an object is usually encoded in the phase of a recorded fringe patte ...

2011

Simultaneous measurement of in-plane and out-of-plane displacement derivatives using dual-wavelength digital holographic interferometry

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

The paper introduces a method for simultaneously measuring the in-plane and out-of-plane displacement derivatives of a deformed object in digital holographic interferometry. In the proposed method, lasers of different wavelengths are used to simultaneously ...

Optical Society of America2011

Application of complex-lag distributions for estimation of arbitrary order phase derivatives in digital holographic interferometry

Pramod Rastogi, Rajshekhar Gannavarpu

This Letter proposes a method to estimate phase derivatives of arbitrary order in digital holographic interferometry. Based on the desired order, the generalized complex-lag distribution is computed from the reconstructed interference field. Subsequently, ...

Optical Society of America2011

Investigations to realize a computationally efficient implementation of the high-order instantaneous moments based fringe analysis method

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

Recently, a high-order instantaneous moments (HIM)-operator- based method was proposed for accurate phase estimation in digital holographic interferometry. The method relies on piece-wise polynomial approximation of phase and subsequent evaluation of the p ...

2010

Comparative Analysis of Various Single-tone Frequency Estimation Techniques in High-order Instantaneous Moments Based Phase Estimation Method

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

For phase estimation in digital holographic interferometry, a high-order instantaneous moments (HIM) based method was recently developed which relies on piecewise polynomial approximation of phase and subsequent evaluation of the polynomial coefficients us ...

AIP Conf. Proc.2010

Estimation of Phase in Fringe Projection Technique Using High-order Instantaneous Moments Based Method

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

For three-dimensional (3D) shape measurement using fringe projection techniques, the information about the 3D shape of an object is encoded in the phase of a recorded fringe pattern. The paper proposes a high-order instantaneous moments based method to est ...

AIP Conf. Proc.2010

Estimation Techniques in Phase Shifting Interferometry

Pramod Rastogi, Abhijit Patil, Rajesh Langoju

2010

Generation of a high depth of focus with constant transversal spot size using a phase-only pupil filter

Pramod Rastogi, Daniel Iwaniuk

A novel approach is proposed to obtain an extended depth of focus (DoF) in white light with constant transversal spot size within the DoF. It combines a phase-only pupil filter based on multiplexed radial zones with alternating quartic phase functions. The ...

Taylor & Francis2010

Comparative Study of Three Bayesian Filtering Approaches for Phase Step Estimation in Optical Interferometry

Pramod Rastogi, Abhijit Patil

This paper presents three recursive Bayesian filtering approaches in phase shifting interferometry involving a piezoelectric device (PZT). The three approaches are extended Kalman filtering, unscented Kalman filtering, and particle filtering. These approac ...

2010

Estimation of phase derivative using adaptive window spectrogram

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

The paper introduces an adaptive-window-spectrogram-based method to directly estimate the phase derivative from a single fringe pattern. The proposed method relies on estimating the phase derivative using spectrogram peak detection for a set of different w ...

2010

Estimation of displacement derivatives in digital holographic interferometry using a two-dimensional space-frequency distribution

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

The paper introduces a two-dimensional space-frequency distribution based method to directly obtain the unwrapped estimate of the phase derivative which corresponds to strain in digital holographic interferometry. In the proposed method, a two-dimensional ...

Optical Society of America2010

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