On Sat, 28 Apr 2007 18:42:50 +0200, Jasper Schalken
<[EMAIL PROTECTED]> wrote:
> Isn't it possible for the code to simply disregard pixels outside the
> image? That is, instead of pretending they actually exist and have a
> colour (if it works as I described above, that colour being the
> average of all the other pixel's colours), just don't include them in
> the blur at all. Only blur with pixels that do exist.
> But someone should have a look at the code before I take my
> assumptions/theories too far. I will have another look and see if I
> can understand what it is doing.
You could have a look at the matrix convolution filter code. (Be warned
there are some minor bugs concerning edge effects IIRC) but it will serve
as an introduction to the different ways of treating edge data.
Many algorithms , from the various interpolation methods to the many
filters based on matrix convolution of which blur is an example, can
require data outside the image to function upto the edge.
This has quite simply to be made up by one means or another. There are
several strategies whose suitabilities generally depend on the image
So in short , no, they cant just be ignored.
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