I have made a mosaic of several old orthoimages. If it's possible, I'd like to do two things with the mosaic.
First item is to remove the edges of the smaller rasters that show up in the mosaic, so that the mosaic is more continuous looking. The edges show up as black strips and kind of break up the mosaic along where individual rasters lay on top of other rasters.
The second item is to try to even out the "color" in the images. These images are black and white and they come from scanning in the original b.&w. photos. Likely an artifact of the film, or maybe the scanning process (although I scanned all of these and did everything the same), one run of the orthophotos appears darker in the mosaic. I don't know if this is possible to fix. And if it is, if it won't mess up the rest of the detail of the mosaic.
While researching this question, another question pointed out tools in Arc that seemed useful. I don't know a lot about working with rasters (or GIS for that matter) and I tried these, but they don't seem to have changed much.
I am open on tools, Arc, R, QGIS, but I need some specific instructions if there is any Python code involved. Here is an image of the mosaic and an inset to point out what I mean about the uneven "color" of the mosaic.
I tried the methods suggested here and the raster images don't display. Instead, if I am at the full scale of the mosaic, 1:156,888, there is a framework, the "footprint", of the individual rasters, that kind of looks like a skeleton. If I zoom down to one raster, everything is the same shade of grey, no detail or features. FWIW, in the TOC, the Image has values between 2147483647 and -2147483648.