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Sai Siva Gorthi

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Publications associées (28)

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Phase estimation in digital holographic interferometry using cubic phase function based method

Pramod Rastogi, Sai Siva Gorthi

The paper introduces a cubic-phase-function based method to estimate interference phase in digital holographic interferometry. The proposed method relies on piecewise polynomial approximation of phase by dividing an arbitrary row/column of the complex reco ...

Taylor & Francis2010

Piecewise polynomial phase approximation approach for the analysis of reconstructed interference felds in digital holographic interferometry

Pramod Rastogi, Sai Siva Gorthi

This paper proposes a new approach for the analysis of reconstructed interference fields in digital holographic interferometry. In the proposed approach the interference phase to be estimated is conceived as a piecewise polynomial signal; consequently, eac ...

Institute of Physics2009

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 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

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 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

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

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

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

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

Measurement of in-plane and out-of-plane displacements and strains using digital holographic moiré

Pramod Rastogi, Sai Siva Gorthi, Rishikesh Dilip Kulkarni

The paper proposes a non-destructive method for simultaneous measurement of in-plane and out-of-plane displacements and strains undergone by a deformed specimen from a single moire fringe pattern obtained on the specimen in a dual beam digital holographic ...

Taylor & Francis2014

Improved high-order ambiguity function method for the estimation of phase from interferometric fringes

Pramod Rastogi, Sai Siva Gorthi

Optical Society of America2009

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

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

Numerical analysis of fringe patterns recorded in holographic interferometry using high-order ambiguity function

Pramod Rastogi, Sai Siva Gorthi

This letter introduces a new approach for the demodulation of fringe patterns recorded in holographic interferometry using high-order ambiguity function (HAF). The proposed approach is capable of retrieving the phase from a single fringe pattern. The main ...

Taylor & Francis2009

Simultaneous measurement of displacement, strain and curvature in digital holographic interferometry using high- order instantaneous moments

Pramod Rastogi, Sai Siva Gorthi

2009

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

Discrete chirp Fourier transform based analysis of reconstructed interference fields in digital holographic interferometry

Pramod Rastogi, Sai Siva Gorthi

Taylor & Francis2009

Windowed high-order ambiguity function method for fringe analysis

Pramod Rastogi, Sai Siva Gorthi

American Institute of Physics2009

Spatial Fringe Analysis Methods and their Application to Holographic Interferometry and Fringe Projection Techniques

Sai Siva Gorthi

To date, no fringe analysis technique has the capability to provide simultaneous and direct estimation of the continuous distributions corresponding to the interference phase and its first and second-order derivatives within the framework of a single inter ...

EPFL2010