I have been adding laser scans to one of my projects, and did a few scans the last time I was at the site with my new BLK360. I was able to export the lidar scans from the device to e57 file. I added the lasers to my project and was able to align it with the ~400 hundred photos that I captured via drone and handheld.
When I tried a preview reconstruction, I was done very quickly (as expected) however when I tried Normal, it seemed to hang (working for 12+ hours, no progress.
I then aborted the reconstruction and relaunched RC. When I loaded the saved file, I saw this:
I’m wondering if this is may be causing the problem somehow. Any thoughts on what to do to fix this?
what happens if you re-align? Or better even create a new project, make sure to import the scan first and then the images. With only 400 images, it should not take too too long…
I’ve seen similar screenshots alot lately here in the forum, but can’t remember if there was a solution. Might be some problem with the scans themselves, maybe a bug. If you search I’m sure you will find something.
I hadn’t looked at the coordinate system - where can I find that setting? It’s odd because, before the registration step, the residuals looked normal.
The laser scans were registered before I exported them to e57 files in another application. I did import them as exact. I had actually added a set of drone photos first, then added the laser and then finally added some close-up shots. I’m currently trying again from scratch, starting with the registered e57s, then drone, then closeups. Currently adding control points to get ortho photos from the drone to connect (needed a bunch last time)
The BLK360 is interesting. It’s pretty easy to use, but currently can’t get raw data off it (need to use another piece of software that I’m not crazy about). I’ve also noticed weird stitching, which led to doubling of images. I may need to export individual scans and try to register them in RC as a next step.
Chris - I’ll see if I can figure out how to export multiple e57 or ptx files - rc did end up with 36 las files (I noticed a cube representing the laser scan with each face having its own image
So as I mentioned, I started again and followed the following process.:
set coordinate system to epsg:2278 / Texas South Central (ftUS) for both Project and output
imported e57 (36 files in one component after alignment)
added drone orthos, aligned, added a bunch of control points to merge 4 components
added handheld camera orbit, added a few more control points
added handheld camera detailed shots, added more control points
got component 0 with 2/553, component 1 with 546/553 (not sure what happened to the other 5 pics, but have seen missing pictures before so assuming it’s normal) (see below)
Note no residuals appearing
Normal reconstruction started with an estimated finish time about 50 min ago. What’s interesting is that the progress bar seemed to stop in the same place with the previous attempt.
I’ll let this continue for a few more hours (may just let it chug overnight), but the last time I ended up having to abort and that’s when the residuals appeared.
I think my next step is to try to get individual e57 for each scan (not registered elsewhere) and try to align them in RC.
If anyone has any advice on this, I’d greatly appreciate it.
maybe it has worked if you only did 6 scans and it has imported 36 las files.
it normally makes 6 las files per scan location.
you can also test the align by selecting it all the cameras and clicking on inspect tool. it will show you the connections between all the cameras. and you look for lots of connections esp. between drone, laserscan and ground photos.
There are only six scans that I brought in to RC… I technically did 2 more but removed them from the registration due to what appeared to be bad stitching either on the BLK360, or the mobile app (they don’t have a scanner specific app yet - forced to used the one by their partner)
Inspect seems to have no connections between laser cubes and the pictures *see below). Not what to make of that since they were detected as part of the component…
ok looks like it needs more connections, which could be causing issues.
I suggest not flying the drone manually. you need to make sure you a move a decent distance between photos
if you can fly a double grid, with camera at 45 degrees. (straight down won’t stitch well)
otherwise multiple overlapping obits or both.
also for walking around do it 3 times moving closer or further away.
I would potentially even walk around the laserscan locations a few times each. just so you have some photos close the scans that can then link back to other photos.
if you can’t get back on site. then using control points might help.
agree with all of those, though at this point I don’t have access to the site again. I do have other pics from a different day which include some POI autopilot orbits, though the green tape that was added to try to allow the flat white surfaces to be picked up wasn’t there the first time out. I worry that’ll be a control point nighmare
My more immediate concern is why RC is not completing the registration at all. I was able to get a preview view (very bloby), but the fact that it sees to be hanging with normal detail is whats troubling
don’t worry about using images from different days. RC can handle differences quite well. I once had a scan from a church where there was entirely different furniture (up to the wall mounted lights) from when I did my shots but it still worked fine. So if there is no change in geometry, there should be no problem at all. RC will just use the taped images for the boxes, but the laserscan should be much better suited for that anyway.
I also wouldn’t worry too terribly much about the missing blue lines since there is a threshold (which you can change). As long as the scans are in the right location and you don’t get any noise or doubled surfaces (steps), which is an alignment issue, then you should be fine.
BTW, I just looked at one of the images Tim uploaded for me and I am afraid that there is way too much post processing going on for any significant detail, it’s basically a mosaic. It’s better to have more noise than too much processing.
And I agree with Chris, the camera standpoints are not ideal - you need to think in sweeps (structure from MOTION, as in video) than in panoramas. Everything needs to be connected like a spider web - the more “arms” the better. In addition to circling at different distances, different levels have the advantage of covering geometry at different hights better (e.g. close to the floor).
Looks like it did make it through the normal texturing.
I’m going to attempt bringing in all the photos (from two separate shoots). It’ll be interesting to see what happens given that the lighting conditions were pretty different (overcast vs bright sun), and the tape isn’t on the first set of pics.
I think I’ll also attempt to bring in individual laser scans (ie not registered elsewhere) and see if I can get them to work
In my opinion it will only influence the texture, which you will probably not even notice since RC creates an average for each pixel. But you can modify the result by deactivating the undesired images (e.g. the ones with the tape) before texturing…
@Götz Tim was experimenting with a few different things, hence the different questions on very similar photosets :). This has helped confirm our own understanding of things beyond the general best practices that we’ve found online for photogrammetry. Unfortunately, getting to understand all the functions in RC has been a challenge - with the minimal documentation available. Doing our own controlled experiments have been the only way to understand the nuances of RC. This forum has been very helpful so thanks to you and Chris and everyone else that gave us some guidance
One thing that I was wondering, re. shiny opaque surfaces like metal (say a car) - would shooting with a polarized lens help? Just another thought for future work.
- just joined 2 weeks ago and came the site when we did the reshoot at.