[GRASS-user] stitching together aerial imagery with edge blending

[Henry House]

I have a selection of vintage aerial imagery from 1929 which features
variable brightness, with edges of images generally overly dark. While
I'm grateful that imagery from 1929 exists at all for my study area,
this is annoying and detrimental to classification efforts. As most of
the images overlap each other around their edges, I'd like to blend the
pixels from area where the raster overlap in some way, ideally such that
there are no sharp changes visible in transition from one exposure to
another in the patched map.

I can patch the images together with r.patch, but then I get the
artifacts of the edges. I also thought using r.mapcalc to blend pixels
pixels 50/50 where maps overlap. But surely this has been done many
times before and I can avoid inventing my own method. Do there exist any
specialized tools for smart stitching of aerial imagery tiles together
such that overlapping area a blended; or could someone suggest a good
technique?

--
Henry House
House Agricultural Consultants