Transformation from a quadrilateral to a rectangle

What is the necessary procedures in transforming a perspective image of a tennis court into a "map" like image?

I would like to know how can I go about this in terms of the coding part.

Thanks.

Answer 1

[rondesu]

The title can also be the transformation from a quadrilateral to a rectangle.

Answer 2

[bym]

you need the calibration matrix

or you can browse Zhang's site at Microsoft research where image rectification is done on a whiteboard