Masking Areas in Photos Prior to Upload


#1

I can’t seem to find an answer to this question with a simple search on Google or in this forum - does the DroneDeploy stitching software support masking of areas in photos to hide objects that were moving during the survey (e.g. vehicles and personnel). And, if so, what are the requirements for drawing such masks (e.g. fill masked areas with a specific color or change all mask area pixels to transparent).

This is a useful feature in Agisoft Photoscan as moving objects on an industrial site are unavoidable. I’d like to know as I’ve got a set of photos of a log yard for a client that are waiting to upload and I can see from the Live View rough cut that some of the log loaders are ghosting into the map along their trajectories and it would be nice to erase them from the final image.

Thanks in advance.


#2

Ive never seen it in DroneDeploy, but similar to the post-processing orthomosaic editing in Pix4D right? I use ACDSee as it consistently preserves all EXIF data. There are several tools depending in how you want to redact. Clone, repair, draw, blur and color selection/replace to name a few. You can do the tiles and the orthomosaic. I use to do editing with GIMP, but did have occasional data loss - mostly it was just clunky and you always have to remember to save a copy. ACDSee is non-destructive and automatically saves originals of images you modify.


#3

What you describe in PiX4D sounds like what I’m hoping for in DroneDeploy, although, I’ve never used that so can’t be certain. In Agisoft Photoscan, you can add masked areas to source images. If I recall, it doesn’t actually change the source images, just stores the masked areas in the project file and the alignment engine just uses the coordinates to ignore pixels in those zones while processing the images, replacing them from other, overlapping images which aren’t masked.

I’ve actually got a license of Photoscan Standard, so I’ll process the same photo set in it and compare the output with what comes out of DroneDeploy.

I like DroneDeploy’s easy flight planning, but it’d be a shame if it couldn’t do image masking as most of the sites that I would use it on are industrial with a lot of vehicle and personnel traffic. This particular job is a proof-of-concept sample with the client keen to map the entire site if it works well. We’ll also be checking accuracy of the resulting ortho image by inserting it into a few of their site layout CAD drawings.


#4

I’ve processed the images in DroneDeploy, PiX4D and Agisoft Photoscan Standard and have compared the results.

DroneDeploy and Pix4D orthomosaics are very similar - only minor differences in distortions in tricky areas and they both produced the exact same ‘ghosting’ problem with vehicles on site. They also had similar (though, still noticeably different) levels of success in dealing with a plume of geothermal steam that was blowing across one area of the site on the day and which got caught in a number of images. In general, they dealt with thick steam clouds and shadows thrown by them well,. Only in a couple of images where the steam clouds were slightly transparent did they fail at keeping the clouds out of the final orthomosaic.

However, with manually applied masks in Agisoft Photoscan, I was able to completely eliminate the vehicles, steam clouds and their shadows from the final orthomosaic, producing a clean image of the underlying ground surface.

Masking would be a highly useful addition to DroneDeploy.