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Images that are altered/edited in Photoshop before uploading (removing a structure)

 

If I edit an image in Photoshop before uploading to MME, will it affect the data/data points and resulting map, specifically the elevation map? Example: there is a small man-made structure that appears in the original MME elevation map. If I remove the structure wherever it appears in the mission JPG images and process the same map again but now with the edited images (with the structure removed), will the structure still appear in the elevation map, even though it's visually removed in the JPG images?? Thanks in advance...

 

Old Scout

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In general you shouldn't edit images before upload. They are likely to lose their tag data. You can do color corrections if you must but you have to make sure the EXIF and XMP data remain intact. Pixels should not be moved. 

If they are it is likely going cause accuracy issues overall. It might be OK if it is just a couple of images. It may work but it won't likely work well.

If you use the rubber stamp tool that you used there which duplicates features it will probably cause other issues and the elevation map will possibly have a spike or flat spot in it there due to the mismatches. 

Zane
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Before I posted, I verified the EXIF and XMP did not change in the altered image. I also used Edit > Fill > Content-Aware instead of the clone stamp tool. Same effect. That should not matter for the purposes of this demonstration.

If your hunch is correct, each pixel may contain GPS and altitude data. That would be logical since that how it drew that structure in the first place and displays it on the colorized terrain map. Yes??

I guess the only way to confirm is to run a small mission around that structure and process one map with the structure and one map without. My guess is that it will just produce a duplicate of the original elevation map with the structure visible. I think (guess) the Point Cloud data is stored in another place not associated with the colored pixels in an image.

Old Scout 0 votes
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"If your hunch is correct, each pixel may contain GPS and altitude data. That would be logical since that how it drew that structure in the first place and displays it on the colorized terrain map. Yes??"

Before processing, each pixel contains no elevation data point.  SFM processing assigns a relative elevation data point to each point in the cloud based upon mathematics. Not any information in the meta data.  The meta data is important to tell the processor about the camera/lens and the location where the image was captured.  Not any elevation data about the pixels themselves. That's the processor's job.

The proper way to remove anything from the scene is by editing the point cloud. Then, you generate the DEM (elevation grid or "heatmap") from the edited point cloud.  This is beyond the capability of MME as of now. 

If you just want the shed visually gone from the DSM that MME provides, it would probably be best to just edit it in your editor rather than the source images prior to processing.

Dave Pitman 0 votes
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