Re: [PanoToolsNG] Distortion equation for PTGUI
- Terry Thrift wrote:
> Alan:The only practical computation for computing a destination pixel from a
> It is rarely just a single pixel from the source that is taken for
> each destination pixel.
> You could try thinking of pixels as square areas of a single color.
source area is interpolation.
The usual interpolations are: nearest neighbor; bilinear; bicubic;
Lanczos and Sinc functions.
Nearest neighbor is a gross approximation taking the source pixel
nearest the sub pixel location of the desired
source pixel. The others "invent" a whole new pixel from a neighborhood
around the desired sub pixel location
of the desired source pixel.
For practical reasons, the neighborhood is usually a symmetric square
around the desired sub pixel location with
weights assigned to the actual source pixel depending on how far away
wikipedia has a bunch of good articles on interpolation.