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irSignature class

Infrared platform signature

Description

The irSignature creates an infrared (IR) signature object. You can use this object to model an angle-dependent contrast radiant intensity of a platform. The radiant intensity is with respect to the background.

Construction

irsig = irSignature creates an irSignature object with default property values.

irsig = irSignature(Name,Value) sets object properties using one or more Name,Value pair arguments. Name is a property name and Value is the corresponding value. Name must appear inside single quotes (''). You can specify several name-value pair arguments in any order as Name1,Value1,...,NameN,ValueN. Any unspecified properties take default values.

Properties

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Sampled contrast IR intensity pattern, specified as a scalar, a Q-by-P real-valued matrix. The pattern is an array of IR values defined on a grid of elevation angles and azimuth angles. Azimuth and elevation are defined in the body frame of the target. Units are dBw/sr.

  • Q is the number of IR samples in elevation.

  • P is the number of IR samples in azimuth.

Q and P usually match the length of the vectors defined in the Elevation and Azimuth properties, respectively, with these exceptions:

  • If you want to model an IR pattern for an elevation cut (constant azimuth), you can specify the IR pattern as a Q-by-1 vector. Then, the elevation vector specified in the Elevation property must have length-2.

  • If you want to model an IR pattern for an azimuth cut (constant elevation), you can specify the IR pattern as a 1-by-P vector. Then, the azimuth vector specified in the Azimuth property must have length-2.

Example: [10,0;0,-5]

Data Types: double

Azimuth angles used to define the angular coordinates of each column of the matrix or array specified by the Pattern property. Specify the azimuth angles as a length P vector. P must be greater than two. Angle units are in degrees.

Example: [-45:0.5:45]

Data Types: double

Elevation angles used to define the coordinates of each row of the matrix or array specified by the Pattern property. Specify the elevation angles as a length Q vector. Q must be greater than two. Angle units are in degrees.

Example: [-30:0.5:30]

Data Types: double

Methods

valueInfrared intensity at specified angle and frequency

Examples

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Create and display an IR intensity signature. The signature depends on azimuth and elevation.

Define the azimuth and elevation angle sample points.

az = -90:90;
el = [-30:30];

Create the IR intensity signature pattern.

pat = 50*cosd(2*el.')*cosd(az).^2;
irsig = irSignature('Pattern',pat,'Azimuth',az,'Elevation',el);

Display the IR pattern.

imagesc(irsig.Azimuth,irsig.Elevation,irsig.Pattern)
xlabel('Azimuth (deg)')
ylabel('Elevation')
title('Infrared Signature Pattern (dBw/sr)')

Get the IR intensity value at 25 degrees azimuth and 10 degrees elevation.

value(irsig,25,10)
ans =

   38.5929

Get IR intensity value outside of the valid elevation span.

value(irsig,25,35)
ans =

  -Inf

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

See Also

Classes

Introduced in R2018b