On Jan 7, 10:29 pm, Tom Sharpless <[email protected]> wrote:

>  Since I used a PT-
> based stitcher, the results are polynomial coefficients describing the
> deviation of the lenses' curves from the function r = f  *  theta,
> where f is focal length, r and f are in pixels, and
> theta is in radians.  Or would be, except that the PT polynomial has
> been tweaked to hold the r value corresponding to half the smaller
> image dimension constant.  It is straightforward to calculate the
> coefficients of the preferable polynomial, that has constant unit
> slope at image center (and so does not alter the apparent focal
> length).  To do that you need the factor by which PT multiplied the
> 'ideal radius' input to the polynomial -- which unfortunately it
> neither prints nor saves.

Let me be more specific.  To convert PT's coefficients to the
coefficients of the equivalent slope-normalized polynomial, one must
multiply them by appropriate powers of a factor I call PT's radial
scale factor, rsf.  In libpano the input to the radius-normalized
polynomial is
(radial distance in pixels) / (0.5 * min(wid, hgt).

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