"fuzzy" border around georeferenced air photos

KevinDurkee · ‎07-20-2021

Were having some issues with a newly created mosaic dataset from 1970's tiff air photos. One being visualizing at different scales, might just need to redo the pyramid/overviews the other I can't figure out. There's almost a white "pixelly" border around each tiff very clearly showing the stich lines. It is scale dependent, further out extremely noticeable, closer in almost disappears. Below are two images for references. Anyone know what might be causing this?

Any help would be much appreciated!

Thanks!

PeterBecker · ‎07-20-2021

It would appear that the source images have a white border, are JPEG compressed, and you have defined white as being no data. The footprint currently is probably the envelope of the image. What is happening is that as in the pyramids of each image the lower resolution images are being created using JPEG compression and the pure white is no longer white so at lower scales they are no longer NoData/Transparent. The solution to this is to Build footprints by radiometry (say approx 20 vertices and shrink distance of 100m. This should result in a footprint being created around each image and it being clipped by the footprint so excluding all the white areas more cleanly. You should find that after this modification the dynamic mosaic will display faster. Now if you re-build the overviews the artifacts should go away. Also note that you can generate seamlines which will also determine the optimum location for the join. To further reduce any noticeable transition look to set a blend width (say 10pixels) on the seamlines. Also consider running the color correction tools which will further remove trends between different images.

View solution in original post

PeterBecker · ‎07-20-2021

It would appear that the source images have a white border, are JPEG compressed, and you have defined white as being no data. The footprint currently is probably the envelope of the image. What is happening is that as in the pyramids of each image the lower resolution images are being created using JPEG compression and the pure white is no longer white so at lower scales they are no longer NoData/Transparent. The solution to this is to Build footprints by radiometry (say approx 20 vertices and shrink distance of 100m. This should result in a footprint being created around each image and it being clipped by the footprint so excluding all the white areas more cleanly. You should find that after this modification the dynamic mosaic will display faster. Now if you re-build the overviews the artifacts should go away. Also note that you can generate seamlines which will also determine the optimum location for the join. To further reduce any noticeable transition look to set a blend width (say 10pixels) on the seamlines. Also consider running the color correction tools which will further remove trends between different images.

KevinDurkee · ‎07-21-2021

Fantastic! I did both the build footprints and the seamlines and the artifacts did in fact go away. Thank you for your help!