Affine transformation is a two-dimensional coordinate (x, y) to two-dimensional coordinates (u, v) of the linear transformation.
Homogeneous coordinates corresponding to the matrix representation:
Affine transformation features:
- It remains straight after the affine transformation by linearly;
- 'Relative positional relationship between the straight line remains unchanged after the affine transformation by parallel lines remain parallel lines, and a point on a straight line in order of position does not change;
- Three pairs of corresponding points to determine a non-collinear unique affine transformation;
After the affine transformation, the image is still critical points form a triangle, the triangular shape has changed.
Summary: is multiplied by a matrix, eigenvector matrix determines the direction of image transformation.