Image processing of Ramses II statue using speckle photography modulated by a new Hamming linear aperture (original) (raw)
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Optics and Photonics Journal, 2011
A computer generated quadratic and higher order apertures are constructed and the corresponding numerical speckle images are obtained. Secondly, the numerical images of the autocorrelation intensity of the randomly distributed object modulated by the apertures and the corresponding profiles are obtained. Finally, the point spread function (PSF) is computed for the described modulated apertures in order to improve the resolution.
Recognition of Direction of New Apertures from the Elongated Speckle Images: Simulation
Optics and Photonics Journal, 2013
In this paper, we present an elongated speckle images produced from diffusers using sharp elliptical apertures. The orientation of the elliptic aperture is recognized from the direction of the elongation in the speckle images. The aperture tilting out of the plane is investigated. Three models of elliptical apertures are considered and the corresponding speckle images are obtained. The 1st model is composed of two orthogonal ellipses or plus symbol pupil; the 2nd has four symmetric ellipses with an angle of 45˚ between each of them or in the form of a snow flake pupil and the 3rd model looks like an airplane. Also, the autocorrelation profiles of the speckle images corresponding to the diffused airplane are obtained from which the average speckle size is computed. Finally, the reconstructed images of the described elliptical models and its autocorrelation images, making use of Mat lab code, are obtained.
The computation of the average speckle size from the point spread function for triangular apertures
The European Physical Journal Plus
We suggest triangular aperture modeling for the computation of speckle size using the point spread function (PSF) concept. The fast Fourier transform (FFT) algorithm indicates three models of triangular apertures in the point spread function (PSF) computation. We calculated for the first time the average speckle size from the full width at half maximum (FWHM) for the triangular apertures in the PSF. The results are compared with the speckle sizes results obtained from the autocorrelation of speckle images corresponding to the considered models showed an agreement. In the analysis, I consider the 1st model with four equilateral triangular apertures, each of equal sides (b), along the Cartesian coordinates at equal distances from the center (xd). In the 2nd model, I assume 16 triangular apertures in a circular contour. In contrast, in the 3rd model, a sequence of six equilateral triangular black and white (B/W) zones is shown where the central triangle is black. I consider central obs...
New multiple aperture arrangements for speckle photography
Optics Communications, 2000
We propose a multiple exposure specklegram by using an optical system whose multiple aperture pupil changes between exposures. In particular, we analyze experimentally two arrangements and we show that it is possible to store the required information by employing a minimum number of registers if an adequate selection of the pupil is done. We study the effect Ž . of the decorrelation among the stored speckle pattern introduced by changing the multiple aperture pupil arrangements between exposures. The fundamentals and the relative benefits of the new scheme proposed are discussed on the basis of a fringe visibility analysis. q 2000 Published by Elsevier Science B.V.
Application of the Fourier transform in electronic speckle photography
Experimental Mechanics, 2002
In speckle photograph technology, to determine the displacement of the points on the surface of the measured body, the conventional method is to put the film which has recorded the speckle patterns before and after displacement into a system of optical Fourier transforms. After filtering on the spectrum plane, the experimentalist can obtain the displacement information from the interference pattern on the image plane. Instead of setting up a complex optical Fourier transform system, we consider the speckle field as a light intensity function of 2 dimensions, which will change with different positioning of the points. After working on the function's discrete Fourier transform (DFT), according to one of the properties of Fourier transformation, the displacement of the measured point is involved in the phase of its spectrum. Having extracted the displacement information from the phase, we obtain the distribution of the displacement field. In this paper, we deduce the expression for the displacement field by using Fourier transformation under conditions of both equal and unequal displacement and show their applications.
Properties of speckle patterns generated through multiaperture pupils
Optics Communications, 2001
The characteristics of the image speckles obtained through multiple aperture pupils are theoretically analyzed in terms of the parameters de®ning the pupils. The possibility of interpreting and synthesizing the image speckle distribution in terms of rather elementary structures is considered, based on the Fourier optics analysis. Then, ®rst and second order statistical properties of the speckle patterns are studied by evaluating both the mutual intensity and the auto-correlation intensity of speckle distributions obtained by means of pupils consisting of identical apertures. Experimental results are presented to con®rm the analysis. Ó 2001 Published by Elsevier Science B.V.
Fringe visibility analysis with different scale apertures in speckle photography
Journal of Modern Optics, 2001
The use of different scale aperture pupils for image recording in speckle photography is analysed. In particular a double-exposure specklegram is considered. The ensemble-average intensity in the Fourier plane is analytically derived and fringe visibility is investigated. The theoretical results are verified by in-plane displacement translation experiments.
Multiple-aperture speckle method applied to local displacement measurements
Optics Communications, 2007
The goal of this work is to analyze the measurement capability of the modified speckle photography technique that uses different multiple aperture pupils in a multiple exposure scheme. In particular, the rotation case is considered. A point-wise analysis procedure is utilized to obtain the fringes required to access to the local displacement measurements. The proposed arrangement allows simultaneous displaying in the Fourier plane several fringes system each one associated with different rotations. We experimentally verified that the local displacement measurements can be determined with a high precision and accuracy.
Double-exposure specklegrams obtained by using scaled aperture pupils
4th Iberoamerican Meeting on Optics and 7th Latin American Meeting on Optics, Lasers, and Their Applications, 2001
In speckle photography the pupil aperture is usually not modified between exposures. In our work, the change of the pupil aperture scale between exposures is analysed on the basis of double-exposed image speckle, before and after a diffuser inplane displacement is done. The apertures have the same shape but its scale is modified between exposures. Note that the relative position of the aperture is maintained. In particular, we analyse a simple case that uses a circular aperture whose diameter is modified for recording each image. The intensities in the image plane and the fringe visibility are evaluated, in terms ofthe geometric characteristics ofthe pupils.
Optics and Photonics Journal, 2013
The paper is devoted to study theoretically, the effects of some parameters on the visibility of the speckle patterns. For this propose, a theoretical model for a periodic rough surface was considered. Using this theoretical model, the effects of grain height, its density, the band width and spectral distribution of the line profile (Gaussian and Lorentzian) illuminating a rough surface on the visibility of speckle pattern are investigated. An experimental setup was constructed to study the effect of surface roughness and coherence of the illuminating light beam on the contrast of speckle pattern. The general behavior of the experimental results, which agree with published data, is compatible with the new theoretical model.