Adding oblique and ground based imagery to your solution

[S&S_Shovelhead]

Is anyone out there taking oblique imagery with your drone in addition to your nadir images? Is there a flight planning app that allows you to do this or are you flying and snapping the pics manually? If so how to you determine your overlap?
Also is anyone taking ground based images with a SLR and processing then together with their uav images? How do you go about this getting the images to stitch together with the aerial images?

 

[doktorinjh]

We've been using the Pix4DCapture App for flight planning and it has the option to do 2D and 3D flight planning. The 2D takes pictures from 0 degrees to nadir orientation and does a "single grid" flight plan (only goes in a N/S or E/W). The 3D plan allows camera orientations from 45-80 degrees and flies a "double grid" (flies N/S and E/W) for 3D reconstruction. Most apps will have similar functionality and also allows you to set the UAV's speed, overlap, height, etc. If anything, the app collects more pictures than needed, so the overlap has always been fine.

You're likely better off flying oblique imagery rather than ground based shots for better software alignment. It can be done, but you have to keep in mind that the software tries to match points in images to create the 3D point cloud and orthomosaic. If your photos from the ground are of the side of a building and your flights are flown nadir, then you're not likely to get good overlap and matching. And, unless your camera has the ability to add georeferencing, then the processing will have even more difficulty. So, I would recommend oblique UAV imagery to enhance your mapping, rather than SLR imagery.

 

[S&S_Shovelhead]

We've been using the Pix4DCapture App for flight planning and it has the option to do 2D and 3D flight planning. The 2D takes pictures from 0 degrees to nadir orientation and does a "single grid" flight plan (only goes in a N/S or E/W). The 3D plan allows camera orientations from 45-80 degrees and flies a "double grid" (flies N/S and E/W) for 3D reconstruction. Most apps will have similar functionality and also allows you to set the UAV's speed, overlap, height, etc. If anything, the app collects more pictures than needed, so the overlap has always been fine.

You're likely better off flying oblique imagery rather than ground based shots for better software alignment. It can be done, but you have to keep in mind that the software tries to match points in images to create the 3D point cloud and orthomosaic. If your photos from the ground are of the side of a building and your flights are flown nadir, then you're not likely to get good overlap and matching. And, unless your camera has the ability to add georeferencing, then the processing will have even more difficulty. So, I would recommend oblique UAV imagery to enhance your mapping, rather than SLR imagery.

Thank you for the thorough reply.

If I were to add terrestrial images I would definitely fly oblique images as well.
So you would suggest purchasing a camera that has GPS capabilities?

 

[doktorinjh]

So you would suggest purchasing a camera that has GPS capabilities?

It certainly wouldn't hurt, or... you can geotag regular images using the GeoSetter freeware tool. That will help the program know approximately where the photos were taken. If you're looking for GPS for an existing camera, I know they make hot shoe add-ons for several SLRs, but you might also have success with a Canon S100 for much cheaper.

 

[S&S_Shovelhead]

Here's an interesting article I ran across that shows that capabilities of terrestrial photogrammetry when combined with uav photogrammetry. The results are pretty amazing, I just wonder after everything is said and done, if conventional surveying is much quicker. I may have to do a field comparison soon.

Link: https://www.google.ca/url?sa=t&sour...ggfMAA&usg=AFQjCNEPX1915mmFGgQGAnO62pKM4JMrsg

 

[RocketBrew]

You also want to ensure that your oblique images do not have the horizon or sky in them. That seems to throw off most software. Seems like that would be more difficult from a terrestrial view.