Combining drone with photogrammetry

[virtuoso]

Hello guys.

We have been using RTC 360 for a year now and it is perferct for the job it does. The problem comes with taller buildings where you can find lot's of obstructions (balconies, wall decorations etc.), not been able to go on the roof etc.. We are thinking about getting drone and combining photogrammetry with laser scans. I assume that I will need separate software for stitching photos together and making pointcloud right? Is it possible to insert it in cyclone software. We are currently using register 360. I assume we would need to use markers for stitching photography and georeference those ?

Also one of our objective is to deliver orthophotos for renovating old buildings etc.

I would be thankful for your advices.

[gschofield]

Hi,
You might want to have a look at Reality Capture by Capturingreality.

https://www.capturingreality.com/

It handles scan and imaging data quite nicely with impressive results.

[LPaulCook]

Recap Pro is very inexpensive and does both.

[virtuoso]

Recap Pro is very inexpensive and does both.

You mean Recap Photo for creating photogrammetry or were you thinking about also inserting for example e57 from laser scan and in that project you can import .las or .xyz depends what output format is for photogrammetry? I was thinking about pix4D. Could come handy because it makes on site job much easier with calculated path and all that stuff.

Our goal is to create orthophotos which recap can't.

[Kansanparantaja]

I've done this using following workflow:
1. Laserscan the site. Register the scans.
2. Take coordinates from visible points from the laser scan point cloud. (e.g. roof corners)
3. Use drone to capture the site from above. Process the dataset in Pix4D and use those coordinates from the laser scan as Ground Control Points (GCP's)
4. Import laser scan and drone point cloud to Recap Pro separately
5. Combine point clouds in Recap.

And btw don't use Pix4D Capture. IMO it is a piece of crap. There are far better alternatives out there.

[virtuoso]

Let's say we are in situation where client doesn't ask about georeferencing pointcloud. Will it be enough for example as you've said, to put some targets on floor, walls...etc. Scan building first with RTC360, put that into Register. Set 0,0,0 somewhere with UCS, then after that inspect points on markers, write those coordinates, and slap those in let's say PIX4d (we plan to use mapper if that, can you do that in mapper or you need additional software?). Will that be enough to create somehow overlap with scanner and drone?

[LPaulCook]

Recap Pro comes with two programs, one for laser scanning and the second program for drone photos which will process the photos into a dense point cloud.
Bring the point cloud from the drone photos into the laser scanned point cloud and manually register the two together by using the edges of the roof that will be common in both point clouds or use other common points to join the two point clouds. Just like you would do for a new scan...

[Buros]

I will try this in Recap.
The point cloud from the laserscandata (A) is more accurate then the point cloud from the drone capturing (B).
Can you tell Recap to not scale A and align B into A?

[LPaulCook]

ReCap says that it can but I would do it in FARO's SCENE software as I'm more use to registering point clouds there. You may have another program that you are more used to also.

If the ground scans are georeferenced re-run that regestration after adding the roof drone scans as one cluster containing both, to be sure everything is georeferenced correctly.

Good luck.