Shadowing of random rough surfaces

Beckmann, P.

doi:10.1109/tap.1965.1138443

Cited by 138 publications

(46 citation statements)

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“…an arbitrary mean level, or in terms of the distribution of surface slopes. So far solutions exist only for one-dimensional surfaces (for example Beckmann, 1965;Saunders, 1967), and I will therefore use a contrived, but convenient model, first introduced by ham6en-Antilla et al (1965). In this model the surface is assumed to be bounded on top by a plane which is punctured by countless paraboloidal craters, whose axes of revolution are perpendicular to the plane.…”

Section: ) the Scattering Properties Of A Small Surface Elementmentioning

confidence: 99%

The Physical Meaning of Phase Coefficients

Veverka

1971

International Astronomical Union Colloquium

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The question of what information about an asteroid's surface is contained in a measurement of the phase coefficient between phase angles of 10° and 30° is examined in detail. Contrary to some past claims it is shown that absolute reflectivities cannot be derived from phase coefficients. Furthermore, typical asteroid phase coefficients cannot be interpreted unambiguously. This is because the observed phase coefficient may depend as much on the photometric properties of an individual surface element as on the degree of large-scale surface roughness, and these two effects are impossible to separate if only disk integrated measurements are available. The wavelength dependence of asteroid phase coefficients should be small and should contain little information about the surface. In the case of irregular asteroids with macroscopically rough surfaces, the importance of large-scale shadowing, and hence the observed phase coefficient, will depend on the aspect of the asteroid. In such cases, therefore, phase coefficients must be carefully defined to be meaningful It should be possible, in some cases, to estimate the relative surface roughness of two quasi-spherical asteroids by combining photometric and polarimetric observations. For example, if the two asteroids have almost identical polarization curves but quite different phase coefficients, it is likely that the asteroid with the larger phase coefficient has a macroscopically rougher surface.

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Section: ) the Scattering Properties Of A Small Surface Elementmentioning

confidence: 99%

The Physical Meaning of Phase Coefficients

Veverka

1971

International Astronomical Union Colloquium

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“…The shadowing effect arises when part of a rough surface may be shadowed by other parts of the surface at a given look angle. It has been shown [20][21][22][23] that the shadowing effect is importan t_ for rough surfaces, particularly at large incident angles and that energy conservation would be violated if the shadowing effect were neglected.…”

Section: -2 Section 2 -The Modelmentioning

confidence: 99%

“…The 6h , dowing function S(9) has been studied by many investigators (20)(21)(22)(23). In this study, the function S (9) given by Wagner [22] is used and it has the form,…”

Section: -2 Section 2 -The Modelmentioning

confidence: 99%

Calculations of the Microwave Brightness Temperature of Rough Soil Surfaces: Bare Field

Mo¹,

Schmugge

Wang

1987

IEEE Trans. Geosci. Remote Sensing

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“…The analytic shadowing function proposed by Beckmann [23] is equal to the illuminated surface portion of the surface, and it varies from one at normal incidence to zero at grazing angle. Another shad-owing function given by Brokelman and Hagfors [24], corresponding to ratio of illuminated point number having a specular refexion over the entire surface points.…”

Section: Introductionmentioning

confidence: 99%

“…In practice some regions of the sea surface may be screened by other parts of the surface. This phenomenon is quantified by the shadowing function equal to the ratio of the illuminated surface [23]. Early developments of shadowing theories (Wagner [19], Smith [20,21]) assume that the shadowing and shadowed point are uncorrelated, involving that the shadowing function is independent of the autocorrelation function.…”

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confidence: 99%

Intrinsic Infrared Radiation of the Sea Surface

Bourlier¹,

Saillard²,

Berginc³

2000

PIER

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Prologue-The infrared contrast of ships at sea is of importance for those who want to detect, identify and achieve target acquisition and for those who want to protect to enhance target vessel's first strike capability and hence its survivability. Infrared signature control or stealth technology is changing the face of naval warfare and is rapidly becoming a key performance parameter in warship design. The infrared contrast is determined by a large number of parameters. Temperatures of the ship structure and the ambient sea and air are important. But the infrared and visible signature is due not only to target emissions but to the immediate target background. Infrared signature designs are driven by signature generation mechanisms and threat sensors characteristics. Definition of threat sensor types (operating bands, resolution capability) helps to focus infrared and visual signature control on the spectral regions and spatial dimensions of greatest interest. One of the more common divisions of the visual or infrared signature definition is the separation based on so-called imaging versus non-imaging sensors. Imaging sensors threats are represented by the human eye and aids such as televisions, FLIRs (forward-looking infrared) and image intensifiers. These threats possess the ability to resolve and process silhouette and internal target pattern detail. Non imaging sensors depend on target signal strength and background separation. Nonimaging sensor threat are represented by missile seekers, IRSTs (infrared search and track) and terminally guided submunitions. The more recent generation IR missile seeker threats use the 3 to 5 µm band, future threat seekers are likely to use imaging focal plane arrays. Infrared search and track systems work in the same 3 to 5 µm band as do missile seekers. Future

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Shadowing of random rough surfaces

Cited by 138 publications

References 1 publication

The Physical Meaning of Phase Coefficients

The Physical Meaning of Phase Coefficients

Calculations of the Microwave Brightness Temperature of Rough Soil Surfaces: Bare Field

Intrinsic Infrared Radiation of the Sea Surface

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