Dr. Peter N. Raven Profile

Dr. Peter N. Raven

Technical Director at Malvern Optical Ltd

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Author

Publications (6)

Proceedings Article | 17 October 2019 Presentation + Paper

Round robin comparison of BRDF measurements

Tomas Hallberg, Daniel Pearce, Peter Raven, Christopher Baker, Richard Moore, Hans Kariis

Proc. SPIE. 11158, Target and Background Signatures V

KEYWORDS: FT-IR spectroscopy, Sensors, Calibration, Spectroscopy, Light scattering, Reflectivity, Bidirectional reflectance transmission function, Integrating spheres

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Proceedings Article | 10 May 2006 Paper

Infrared and visible cooperative vehicle identification markings

Eoin O'Keefe, Peter Raven

Proc. SPIE. 6201, Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security and Homeland Defense V

KEYWORDS: Thermography, Infrared imaging, Visible radiation, Imaging systems, Silver, Coating, Reflectivity, Surveillance, Infrared radiation, High dynamic range imaging

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SPIE Journal Paper | 1 May 2002

Polarized directional reflectance from laurel and mullein leaves

Peter Raven, David Jordan, Catherine Smith

OE Vol. 41 Issue 05

KEYWORDS: Reflectivity, Bidirectional reflectance transmission function, Polarization, High dynamic range imaging, Polarimetry, Absorption, Scattering, Backscatter, Multiple scattering, Optical engineering

Proceedings Article | 18 September 2001 Paper

Comparison of measured BRDF data with parameterized reflectance models

Rupert Watson, Peter Raven

Proc. SPIE. 4370, Targets and Backgrounds VII: Characterization and Representation

KEYWORDS: Infrared imaging, Visible radiation, Data modeling, Reflection, Scattering, Reflectivity, Bidirectional reflectance transmission function, Specular reflections, High dynamic range imaging, Scene simulation

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Proceedings Article | 15 November 2000 Paper

Polarized bidirectional reflectance from leaves in the visible and infrared

Peter Raven, David Jordan, Catherine Smith

Proc. SPIE. 4133, Polarization Analysis, Measurement, and Remote Sensing III

KEYWORDS: Visible radiation, Polarization, Backscatter, Scattering, Sensors, Remote sensing, Reflectivity, Polarimetry, Bidirectional reflectance transmission function, Absorption

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The incorporation of polarisation sensitive optics offers considerable potential for improving the utility of remote sensing imaging systems operating within the visible or infrared wavebands. Systems now exist allowing measurement of the four components of Stokes vector arising from each pixel in the image. In order to develop the interpretation of polarimetric images, knowledge is required of the polarised directional reflectance properties of the materials in the scene, which determine the radiation reaching the sensor. Natural vegetation forms a significant element of many scenes observed with remote sensing systems. Although the size of a leaf may be below the spatial resolution of a system, the reflectance properties of individual leaves will affect the polarimetric data observed. This paper will report the results of measurements of the linear polarised bidirectional reflectance distribution function (BRDF) from two examples of leaves. The polarimetric properties of the directional reflectance from an individual leaf will depend on the surface and volume scattering properties. We report data on two leaves representing extreme cases of the leaf structure. Laurel (prunus laurecatious) has a nacreous surface creating a gloss finish to the leaf. Mullein (verbascum thapsus) has a highly pubescent surface, creating a highly diffuse surface reflectance. Measurements of the linear polarisation BRDF are reported at 632.8nm, 1064nm, 3.39pm and 10.6µm as a function of the polar scatter angles. These wavelengths characterise the polarised reflectance from the leaves under different conditions of absorption and scattering. In both cases the body of the leaf acts a highly diffuse reflector through multiple scattering, but this mechanism is only important when the absorption by the leaf constituents is low. In the spectral regions of moderate and high absorption the surface reflectance dominates. In the case of laurel the surface is relatively smooth, with an associated Brewster angle, whereas the data suggests the layer of hair covering a mullein leaf acts as an array of scattering sources.

Proceedings Article | 25 October 1999 Paper

Bidirectional reflectance from pigmented coatings

Peter Raven, Rupert Watson, John Williams, Paul Milne

Proc. SPIE. 3784, Rough Surface Scattering and Contamination

KEYWORDS: Diffuse reflectance spectroscopy, Data modeling, Polarization, Reflection, Scattering, Optical coatings, Reflectivity, Bidirectional reflectance transmission function, Picosecond phenomena, Systems modeling

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Showing 5 of 6 publications

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