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projective2d

(Not recommended) 2-D projective geometric transformation using postmultiply convention

projective2d is not recommended. Use the projtform2d object instead. For more information, see Compatibility Considerations.

Description

A projective2d object encapsulates a 2-D projective geometric transformation.

Creation

You can create a projective2d object using the following methods:

  • fitgeotrans — Estimates a geometric transformation that maps pairs of control points between two images

  • The projective2d function described here

Description

tform = projective2d creates a projective2d object with default property settings that correspond to the identity transformation.

example

tform = projective2d(A) sets the property T as the specified 2-D projective transformation matrix t.

Properties

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Forward 2-D projective transformation, specified as a nonsingular 3-by-3 numeric matrix. The matrix T uses the convention:

[x y 1] = [u v 1] * T

where T has the form:

[a b c; ...
 d e f; ...
 g h i];

The default of T is the identity transformation.

Data Types: double | single

This property is read-only.

Dimensionality of the geometric transformation for both input and output points, specified as the value 2.

Object Functions

invertInvert geometric transformation
outputLimitsFind output spatial limits given input spatial limits
transformPointsForwardApply forward geometric transformation
transformPointsInverseApply inverse geometric transformation

Examples

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Combine rotation and tilt into a transformation matrix, tm. Use this transformation matrix to create a projective2d geometric transformation object, tform.

theta = 10;
tm = [cosd(theta) -sind(theta) 0.001; ...
      sind(theta) cosd(theta) 0.01; ...
      0 0 1];
tform = projective2d(tm)
tform = 
  projective2d with properties:

                 T: [3x3 double]
    Dimensionality: 2

Examine the value of the T property.

tform.T
ans = 3×3

    0.9848   -0.1736    0.0010
    0.1736    0.9848    0.0100
         0         0    1.0000

Extended Capabilities

Version History

Introduced in R2013a

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