Publications by Sai Siva Gorthi

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

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

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

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

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

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