نتایج جستجو برای: interferogram

تعداد نتایج: 551  

Journal: :Applied optics 1995
M P Georges P C Lemaire

A bismuth silicon oxide crystal is used in the diffusion regime as a dynamic recording medium in a real-time holographic interferometer based on anisotropic self-diffraction. This device is connected with an interferogram-analysis method that uses the phase-shifting technique for quantitative measurement of diffusive-reflecting object deformations. In addition to the usual error sources in phas...

2001
Shen Chiu

Abstract—The SAR interferogram, defined as the product of the first channel and the complex conjugate of the second, is one way of comparing two SAR channels. When the two subapertures are aligned along the flight path, targets with nonzero radial velocities can be detected by exploiting the phase information of the interferogram. This paper examines the effect of clutter interference on the in...

Journal: :Applied optics 1989
M Kajanto E Byckling J Fagerholm J Heikonen J Turunen A Vasara A Salin

We consider the fabrication of high-quality interferogram-type diffractive optical elements with conventional photolithographic techniques and compare the results with those achievable with electron-beam lithography. The fringes associated with the phase transfer function of the binary phase holographic interferogram are approximated with rectangles, which can be realized at submicron accuracy ...

Journal: :Optics express 2012
Julien Roy Jean-Daniel Deschênes Simon Potvin Jérôme Genest

Interferograms from a dual-comb spectrometer are continuously corrected and averaged in real-time. The algorithm is implemented on a field-programmable gate array (FPGA) development board. The chosen approach and the algorithm are described. Measurements with high signal-to-noise ratio, resolution and bandwidth are shown to demonstrate the accuracy of the optical referencing and the processing ...

Journal: :EURASIP J. Adv. Sig. Proc. 2008
Vidhyasaharan Sethu Eliathamby Ambikairajah Linlin Ge

This paper describes a technique for noise reduction in synthetic aperture radar interferometry. The noisy interferogram is decomposed using undecimated wavelet transform and the coefficients are weighted. A novel method for computing the weights for each subband, based on an estimate of the relative noise content in them, is presented with a median filter used as the noise estimator. The propo...

2009
V. Akbari M. A. Rajabi

The application of SAR Interferometry (InSAR) especially in Digital Elevation Modeling as well as deformation monitoring encounters problems due to noise in the interferogram phase. The noise is mainly caused by temporal and baseline decorrelation as well as changes in atmospheric conditions that makes the process of phase reconstruction difficult and reduces the accuracy. The quality of digita...

2004
K. Ren G. Wu V. Prinet

In interferometric synthetic aperture radar (InSAR) processing, simulation of interferogram is a common practice. It is used as synthetic data to test and validate the whole chain of InSAR processing from the interferogram creation to the DEM reconstruction. The objective of this paper is to develop a simulator for validation of geocoding processing and phase-to-height conversion processing alg...

Journal: :JOURNAL OF THE FLOW VISUALIZATION SOCIETY OF JAPAN 1986

2014
R. Udayakumar V. Khanaa

A novel scheme for interferogram filtering is presented in this paper. The main concern of the proposed scheme is to lower the residues count mean while preserving the location and jump height of the lines of phase discontinuity. The real interferogram is converted to complex form by using wrapped phase values as an argument of complex exponentially, placing the data on the unit circle on the c...

2002
David Small Erich Meier Daniel Nüesch

During synthetic interferogram generation (whereby a DEM and platform positions are used to calculate expected fringes), an interpolation step is necessary during the transformation from map geometry into the slant-range geometry of the radar image. Particularly in hilly terrain, assumptions made during the interpolation step can have an impact on the accuracy of the simulation. We investigate ...

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