Manuel wrote:
Hello Wishgranter,
Just a little question:
Which is the best distortion model to use for a normal lens under a normal situation? Division ? Brown 3?
Just some additional notes:
Division is recommended for fish-eyes optics (for example GoPro), reliably covers simple distortions. It works with radial distortion modelled by means of a one-parameter division model.
Brown3 For optics with less than 180°. This is a polynomial model of radial distortion with 3 modelling parameters. It is used as a default.
Brown4 is able to cover different distortion in the middle and borders of an image. This is also a polynomial model of radial distortion but with 4 coefficients.
Brown3 with tangential2 / Brown4 with tangential2 extend Brown3/Brown4 with tangential distortion, which can compensate offset of optics. Majority of current optics has it negligibly small.
K + Brown3 with tangential2 / K + Brown4 with tangential2 These models add to the Brown model a possibility to optimize the whole camera calibration, including Skew and Aspect ratio. If K + Brown3 with tangential2 / K + Brown4 with tangential2 is not used, by default RC assumes zero skew and aspect ratio as 1.
Brown’s distortion model can be used for radial distortion. The more parameters, meant as changes in polynomials, the more complex deformation.