Speckle from a rough surface when the illuminated region contains few correlation areas: The effect of changing the surface height variance

Chandley, P. J.; Escamilla, H. M.

doi:10.1016/0030-4018(79)90005-1

Cited by 39 publications

(15 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…He also found agreement for standard deviations of the phase fluctuations of about 2ir/3, and reported beyond this weak region results opposite to those for very weak fluctuations : that the theoretical curves were significantly higher than the experimental ones given in [8] . A further theoretical and experimental investigation by Deka et al [10] in the region of strong phase fluctuations indicated that this trend became more accentuated in this region .…”

Section: Introductionmentioning

confidence: 65%

“…Figure 4 the contrast reaching a maximum value above 1 . The increase in contrast with z arises from two factors [8] . The first is that away from the beam waist the phase front is curved, introducing a deterministic phase variation over the area of illumination .…”

Section: Basic Formulationmentioning

confidence: 97%

“…[3] . Ohtsubo and Asakura [7] extended the experimental studies to strong-phase fluctuations in the image plane, and Chandley and Escamilla [8] made a similar study of the diffraction field .…”

Section: Introductionmentioning

confidence: 96%

See 2 more Smart Citations

Speckle Contrast in the Diffraction Field of a Weak Random-phase Screen When the Illuminated Region Contains a Few Correlation Areas

Escamilla

1983

Optica Acta: International Journal of Optics

Self Cite

View full text Add to dashboard Cite

An analysis of the speckle contrast in the diffraction field of a weak random phase screen when the illuminated region contains a few correlation areas is carried out . Curved illuminating wavefronts, and the Fresnel and off-axis terms are considered . The limitations of the method are pointed out . Comparison with a gaussian approximation is made . Some previous studies are examined to obtain a more comprehensive view of the problem . Some of the reasons proposed for observed departures of the theory from experimental results are discussed . . IntroductionJakeman and Pusey [1] made early studies of the normalized standard deviation of the scattered intensity or speckle contrast when the area of illumination includes a small number of correlation areas of a random-phase screen . They were concerned with strong random-phase fluctuations, and the subject was pursued by Jakeman and McWhirter [2] . Fujii et al. [3] reported measurements of the speckle contrast for weak random phase fluctuations, some of which were for areas of illumination smaller than the correlation area of the phase fluctuations . These measurements were taken at the centre of the far diffraction field, and the study was followed by a similar one for the image plane [4] . Several computer simulations were also published [5] . Escamilla [6] carried out an analysis for very weak phase fluctuations which reproduced the form of the speckle contrast variation reported by Fujii et al . [3] . Ohtsubo and Asakura [7] extended the experimental studies to strong-phase fluctuations in the image plane, and Chandley and Escamilla [8] made a similar study of the diffraction field .Fujii [9] analysed both weak and moderately strong phase fluctuations, for detection at the centre of the far field and illumination from plane wavefronts at the waist of a gaussian beam and, in accordance with Escamilla [6], found that for very weak phase fluctuations the experimental curves in [3] were significantly higher than the theoretical ones . He also found agreement for standard deviations of the phase fluctuations of about 2ir/3, and reported beyond this weak region results opposite to those for very weak fluctuations : that the theoretical curves were significantly higher than the experimental ones given in [8] . A further theoretical and experimental investigation by Deka et al. [10] in the region of strong phase fluctuations indicated that this trend became more accentuated in this region . It is important to point out t Present address : Departamento de Fisica Aplicada, CICESE, Apdo . Postal 2732, Ensenada, B .C ., Mexico . Downloaded by [University of Regina] at 17:50 18 November 2014 1656 H . M. Escamilla that all the experimental results mentioned so far are for scattering measurements made on ground glass surfaces, and also that all the theoretical studies mentioned so far are based on the model of correlated gaussian phase fluctuations .Jakeman and McWhirter's study [11] of strong phase fluctuations in the Fresnel and Fraunhofer regions included a different evalua...

show abstract

Section: Introductionmentioning

confidence: 65%

Section: Basic Formulationmentioning

confidence: 97%

See 1 more Smart Citation

Speckle Contrast in the Diffraction Field of a Weak Random-phase Screen When the Illuminated Region Contains a Few Correlation Areas

Escamilla

1983

Optica Acta: International Journal of Optics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Speckle correlation methods [15], [16], [17], [18], which are based on second-order statistics, may work on surface roughness Ra between 1 and 30μm. However, they often need two speckle pattern images, which may be obtained by one of the following methods: changing the incident light angle from the surface, rotating the surface to be measured, using two laser light beams.…”

Section: Specklementioning

confidence: 99%

Measure of roughness of paper using speckle

Pino

Pladellorens

2009

SPIE Proceedings

View full text Add to dashboard Cite

Roughness of a paper surface is particularly important in paper and board destined to be printed. Surfaces are often coated and the amount of coating and method of application used depends on the roughness of the base paper. We present a method of measure of the roughness of the paper based in the analysis of speckle pattern on the surface. Images are captured by means of a simple configuration using a laser and a camera CCD. Then, we apply digital image processing using the co-occurrence matrix, so this method can be considered as a non-contact surface profiling method, that can be used online.

show abstract

“…The first configuration is the one traditionally considered by workers in the ionospheric physics and radio astronomy areas but the second has assumed greater importance recently because of its relevance to the propagation and scattering of laser beams. Both configurations can produce high contrast, non-Gaussian intensity patterns which are sensitive to the detailed structure of the scattering screen.In this paper we present an extension of the above mentioned work [9] to the case of an isotropic twodimensional phase screen in order to make contact with recent experiments [10][11][12]23]. Although the analysis we give here is self-contained, only the principal steps in the mathematics are mentioned for the sake of brevity.…”

mentioning

confidence: 91%

Non-Gaussian scattering by a random phase screen

Jakeman

McWhirter

1981

Appl. Phys. B

View full text Add to dashboard Cite

Abstract. A theoretical investigation of non-Gaussian scattering by a smoothly varying deep random phase screen is presented. New analytical results, valid for arbitrary illuminated area, are derived for the contrast of the intensity pattern in the Fraunhofer region and the effect of two scale sizes in the screen is calculated. PACS: 42.10The scattering of electromagnetic radiation by a random phase-changing screen is a subject of longstanding interest, being relevant to theories of, for example, ionospheric scattering of radio waves [1], stellar scintillation at optical and radio frequencies [2,3], rough surface scattering [4], dynamic scattering in liquid crystals [5], and optical propagation through the atmosphere [6]. There is an extensive literature on the theoretical solution of this problem following the pioneering work of Booker et al. [7], Ratcliffe [8] and others in the 1950's and the weak scattering case, when the screen introduces path differences much smaller than the radiation wavelength, is now well understood. The opposite deep phase screen limit has always presented more difficulties both in analytical and numerical treatments of the problem. In order to facilitate calculations in this case we have recently attempted to identify the r61e of interference, diffraction and geometrical optics in an analysis of the dependence of the scintillation behind a deep random phase screen with one-dimensional corrugations on the phase correlation function [9]. We investigated two scattering geometries t) scattering of an incident plane wave into the Fresnel region and 2) scattering of a Gaussian beam into the Fraunhofer region. The first configuration is the one traditionally considered by workers in the ionospheric physics and radio astronomy areas but the second has assumed greater importance recently because of its relevance to the propagation and scattering of laser beams. Both configurations can produce high contrast, non-Gaussian intensity patterns which are sensitive to the detailed structure of the scattering screen.In this paper we present an extension of the above mentioned work [9] to the case of an isotropic twodimensional phase screen in order to make contact with recent experiments [10][11][12]23]. Although the analysis we give here is self-contained, only the principal steps in the mathematics are mentioned for the sake of brevity. We calculate only the scintillation index or contrast of the intensity pattern and assume that the phase function is joint-Gaussian distributed with "smooth" correlation function. New results include analytical formulae valid in the Fraunhofer region for arbitrary illuminated area and Fresnel region plots for the case when the screen is characterized by two distinct scale lengths. The latter represents a useful intermediate situation between the smooth single scale models favoured in early theoretical treatments of the problem [13] and fractal or multi-scale models currently under investigation [14]. General TheoryThe formal solution of the scattering problem illustra...

show abstract

Speckle from a rough surface when the illuminated region contains few correlation areas: The effect of changing the surface height variance

Cited by 39 publications

References 11 publications

Speckle Contrast in the Diffraction Field of a Weak Random-phase Screen When the Illuminated Region Contains a Few Correlation Areas

Speckle Contrast in the Diffraction Field of a Weak Random-phase Screen When the Illuminated Region Contains a Few Correlation Areas

Measure of roughness of paper using speckle

Non-Gaussian scattering by a random phase screen

Contact Info

Product

Resources

About