9
Computing Affine Transformations
between Sets of Matching Points
P1=(x1,y1)
P2=(x2,y2)
P3=(x3,y3)
P2
´=(u2,v2)
P1
´=(u1,v1)
P3
´=(u3,v3)
Given 3 matching pairs of points, the affine transformation
can be computed through solving a simple matrix equation.
u1
u2
u3
a11
a12
a13
x1
x2
x3
v1
v2
v3
=
a21
a22
a23
y1
y2
y3
1
1
1
0
0
1
1
1
1