Hey thanks for that! Im looking at the various filters to try and determine how we are going to deal with the ringing artifacts we have on areas that are superbright. I saw rangecompress function, which helps but at least in my test image the specular reflection component is so bright I get the black artifacts with almost any filter with negative lobes.
IBA::rangecompress()/rangeexpand(), and oiiotool --rangecompress / --rangeexpand compress the excess >1 values of HDR images to a log scale (leaving the <= 1 part linear), and re-expand to the usual linear scale. This is very helpful to reduce ringing artifacts that can happen when an HDR image is resized with a good filter with negative lobes (such as lanczos3), by doing a range compression, then the resize, then range expansion. It's not mathematically correct and loses energy, but it often makes a much more pleasing result. On Wed, Oct 9, 2013 at 6:35 PM, Larry Gritz <[email protected]> wrote: > I think you want > > oiiotool input.ext --resize:filter=blackman-harris 50% -o > /tmp/test.exr > > options are appended to commands with the ":name=val" format. > > Filter choices (see end of filter.cpp) are box, triangle, gaussian, > sharp-gaussian, catmull-rom, blackman-harris, sinc, lanczos3, > radial-lanczos3, mitchell, bspline, disk. > > The default -- which I think pretty good -- is to use blackman-harris when > magnifying, and lanczos3 when minifying. > > > > On Oct 9, 2013, at 5:04 AM, Ben De Luca wrote: > > > Hi All, > > I was trying to pass a filter option to the resize command, but I > cant figure out what the format should look like. > > > > I thought it might be some thing like. > > > > ./oiiotool -v input.ext --resize 50% filter=blackman-harris -o > /tmp/test.exr > > > > Is that the right sort of format? I looked that the code and I cant > actually see how I can pass in the filter option. > > > > Also, is there a list of implemented filters? > > > > -- > Larry Gritz > [email protected] > > > _______________________________________________ > Oiio-dev mailing list > [email protected] > http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org >
_______________________________________________ Oiio-dev mailing list [email protected] http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org
