[ptx] Optimizing, Stitching and Seaming

[Pablo d'Angelo]

On Mon, 24 Nov 2003, Yili Zhao wrote:

> Hi,
>   I have some questions and ideas about pt algorithm.
>   I remember that Pablo said that the optimizing is done by the 
> Levenberg-Marquardt algorithm. From my math knowledge, when I solve a
> nonlinear optimizing problem, I need a objective function to be minimized
> or maximized, and need approximate values of the parameters to be optimized 
> because nolinear optimizing is sensitive to initial values, otherwise, it will
> obtain local minia. That is why we need to set the yaw, roll, pitch and hfov 
> before optimizing. If I do not consider lens distortion, what is the objective
> function to be solved?

Lens distorition is considered. The function the (sum?) of angular distances
of the control point pairs after transformation into the panorama.

>   After optimizing, I get the yaw, roll and pitch for every image. From my math
> knowledge, I can construct three rotational matrixs based on yaw, roll and pitch,

You get one matrix.

> Then I can transform every image in its 3D space. If the project format is sphere,
> I can project every image in 3D space to its spherical coordinates.

No need for 3d space. We don't care how far away the pixels are, since we
just have one viewpoint where all view rays intersect.

ciao
  Pablo
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