[Radiance-general] Removing black areas in imagemapping

[Thomas Bleicher]

On Mon, Jan 11, 2010 at 12:10 PM, Per Haugaard <perhaugaard at yahoo.dk> wrote:
>
> Dear users,
>
> I am mapping a falsecolor image on a working in a room but there is still some black parts left in the image.
> I have FTINY as a guard against rounding errors but it does not remove everything.

As Andy already wrote, FTINY is a very small value to avoid
rounding errors. You just want to identify pixels which are black
(or nearly black) and the red, green and blue colours in the
falsecolor image. You can use ximage or pvalue to work out
the average value of a black pixel and the intensity of the
colours. I'd expect that 0.1 as a treshold value will give you
better results; you might even go up to 0.5 given that the
contour lines are rather intense.

Regards,
Thomas