cartrite wrote:But I'm still not satisfied with all the leftover null areas. Can't figure out
why that dark stripe surrounds all those bigger null blocks. Maybe I'll stumble on to something soon.
cartrite
I solved that problem after some further thinking about what's going on at the
NULL pixel front The solution sounds easy enough:
Firstly, we agree there is a way to replace ALL NULL pixels by the boxcar average, while leaving the other normal pixels unaffected. This also worked OK for both of us, but as a result, there always remained
a dark narrow frame arround the previous NULL pixel area in the end. Since this was quite a conspicuous artefact, it was unacceptable...
The key point is that these dark pixels were NOT NULL pixels and hence they were not affected in the above operation. This you can study clearly by coloring the special pixels with the respective tool in qview!
Here is an illustration. Only the blue pixels are NULL pixels! The dark frame pixels are apparent:
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All you got to do before elimination of the NULL pixels with the lowpass filter, is to convert the dark frame pixels into NULL pixels
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This I did like so:
Code: Select all
# replace dark 1-3 pixel frames around NULL pixel areas by NULL pixels, too
noisefilter from=Clementine64k.cub to=Clementine64k_nullpix.cub tolmin=15 tolmax=255 samples=3 lines=1 replace=null
noisefilter from=Clementine64k_nullpix.cub to=Clementine64k_nullpix2.cub tolmin=15 tolmax=255 samples=1 lines=3 replace=null
This only associates the pixels of the narrow frame, satisfying TOLMIN=15, as
noiseThe action for noise is replace=null.
Remember the meaning of TOLMIN, TOLMAX?
Note the second lowpass has samples and lines of the boxcar interchanged. It typically converts the horizontal frame pixels to NULLs, while the command above it does the same job for the vertical frame pixels.
The rest remains as before. I now have a 64k Clementine64k.bin input texture that via
your script generates VTs where the previous NULL areas have become VERY unconspicuous. They can only be found after intensive searching in high resolution mode!
Here is the cross check with my final 64k VT set made from that input. After a little searching I am sure you will find the triangular, formerly blue NULL pixel area in this Celestia screenshot: The reduced resolution is of course unavoidable, since all null pixels have been replaced by the AVERAGES of the sourrounding pixels...
Fridger