Bi variate polynomial warping filter?

rfrank · October 5, 2020, 12:46am

I have coefficients a b for a polynomial
X = a0 + a1x + a2y +a3xy + a4x^2 + a5y^2
Y = b0 +b1x + b2y + b3xy + b4x^2 + b5y^2

I would imagine there is an ITK filter for this type of transformation but I don’t seem to find it,

Can someone tell me which filter would work for this warping?

Thanks

Rick

blowekamp · October 5, 2020, 1:34pm

Are you looking to optimize this type of transformation?

I am not aware of such an existing transformation. Perhaps there is one in a remote module that I am not familiar with?

Are you looking to construct a displacement field or b-spline to apply such a transformation?

You could use the PhysicalPointSourceImageFilter to generate a vector image of the x,y location then use the UnaryGeneratorImageFilter and a lambda to apply your equation. If you are using SimpleITK, you can look at the marschner_lobb function for how to use overloaded operators on the points.

zivy · October 5, 2020, 4:05pm

If you are working with SimpleITK, this notebook, section titled “Radial Distortion” has code that should be easily modifiable to do what you want.