Hi there,

I've got a problem, which need to solve the derivative of affine transformation.

For example, a 2D affine transform is:

$\displaystyle A_T(f_{x,y})=\left( \begin{array}{ccc}

a_{11} & a_{12} & a_{13} \\

a_{21} & a_{22} & a_{23} \\

0 & 0 & 1 \end{array} \right)

\left( \begin{array}{c}

x \\

y \\

1 \end{array} \right)=

\left( \begin{array}{c}

x^' \\

y^' \\

1 \end{array} \right)$

Here we got $\displaystyle a_{ij}$, which are 6 affine parameters. Then if we want to get the partial derivative of each parameter $\displaystyle a_{ij}$, which is:

$\displaystyle \frac{\partial A_T}{\partial a}$

May I ask how to solve the equation above please? Thanks.