This table lists all of the transformation types supported by cp2tform , in order of complexity. The table includes the minimum number of control point pairs you must select for each type. The 'lwm' and 'polynomial' transform types can each take an optional, additional parameter . See the syntax descriptions that follow for details. Example 'linear conformal' Use this transformation when shapes in the input image are unchanged, but the image is distorted by some combination of translation, rotation, and scaling.
Straight lines remain straight, and parallel lines are still parallel.
2 pairs 'affine' Use this transformation when shapes in the input image exhibit shearing. Straight lines remain straight, and parallel lines remain parallel, but rectangles become parallelograms. 4 pairs 'polynomial' Use this transformation when objects in the image are curved. The higher the order of the polynomial, the better the fit, but the result can contain more curves than the base image. For more information, see mldivide .