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cvGetPerspectiveTransform
cvGetPerspectiveTransform
Calculates the perspective transform from four pairs of corresponding points.

Name 
Type 
Description 

inSrc 
Point2DArray 
Coordinates of quadrangle vertices in the source image. 

inDst 
Point2DArray 
Coordinates of the corresponding quadrangle vertices in the destination image. 

outM 
Matrix 
Calculated transformation matrix. 
Description
The function calculates the 3x3 matrix of perspective transform, that can be applied to an image using cvWarpPerspective filter.
Examples
The sets of corresponding points drawn on images. Such sets mean that after transform one wants to have points specified in first set transformed to points in second set.
Result of applying output matrix of cvGetPerspectiveTransform with input sets of points shown on images above to sample image using cvWarpPerspective. The cvWarpPerspective filter was used with inDWidth = 300, inDHeight = 300, inBorderMode = BORDER_CONSTANT and inInterpolation = INTER_CUBIC.
Errors
This filter can throw an exception to report error. Read how to deal with errors in Error Handling.
List of possible exceptions:
Error type 
Description 
DomainError 
Each of input array must contain four points in cvGetPerspectiveTransform. 
Complexity Level
This filter is available on Basic Complexity Level.
See Also
 cvWarpAffine – Applies an affine transformation to an image.