Image Transformation

1. Transform the image
2. Rigid Transformations, translation, rotation
3. Affine/projective transformation
4. Degree of freedom for different transformations

image filtering
image warping

g(x)= T(f(x))

change domain of image
g(x)= f(T(x))

Parametric Global Warping
origin(0,0)

rotate Θ

Transformation T
p’ = T(p)

A global and parametric T
– same for any p
– a few numbers(parameters)

As a matrix transform
p’ = Mp

Image Scaling(2D)
– multiply each components by a scalar
– uniform scaling scalar same for x, y
– Non-uniform not same

2D Rotation
(x’, y’), (x, y)
x’ = xcos(Θ)- ysin(Θ)
y’ = xsin(Θ)- ycos(Θ)