SCATMECH > Classes and Functions > Surface Scattering Models > Focussed_Beam_Instrument_BRDF_Model

class Focussed_Beam_Instrument_BRDF_Model

The class Focussed_Beam_Instrument_BRDF_Model calculates the effective BRDF for non-diffusely scattering sample measured with an instrument having a field of view, l_FOV, when the sample is surrounded by air.

Diagram showing the components contributing to the effective BRDF of a sample surrounded by air.

Parameters:

Parameter	Data Type	Description	Default
lambda	double	Wavelength of the light in vacuum [µm]. (Inherited from BRDF_Model.)	0.532
type	int	Indicates whether scattering is evaluated in reflection (0) or transmission (1). (Inherited from BRDF_Model.)	0
substrate	dielectric_function	The optical constants of the substrate, expressed as a complex number (n,k) or, optionally, as a function of wavelength. (Inherited from BRDF_Model.)	(4.05,0.05)
alpha	double	The half angle in degrees of the circular aperture over which the scattering is averaged. Integration is performed over this circular aperture, using a 21-point integration scheme described in Section 25.4.61 of Handbook of Mathematical Functions, by M. Abramowitz and I.A. Stegun, (Dover, New York, 1965).	0
model	BRDF_Model_Ptr	The light scattering model. Note: The parameters above, which are inherited from BRDF_Model, override those parameters of the light scattering model. That is, the parameters lambda, type, and substrate override model.lambda, model.type, and model.substrate, respectively.	Microroughness_BRDF_Model
focal_point	double	This value is defined as the ratio of the sample-focal-point distance to the sample-detector distance. If the incident light is focussed onto the detector circle, the parameter is 1. If it is focussed at the sample, the parameter is 0. The parameter can take any real value.	1

Include file:

#include "focussedbeam.h"

Source code:

focussedbeam.cpp

Definition of public elements:

class Focussed_Beam_Instrument_BRDF_Model
  : public Instrument_BRDF_Model
{
};

For More Information

SCATMECH Technical Information and Questions
Optical Technology Division (OTD) Home Page
OTD Technical Inquiries
OTD Website Comments