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Messages - c-r-o-n-o-s

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Bug Reports / Re: 1.7.3 - Sample Points Bug
« on: August 17, 2021, 03:06:05 PM »
What does the point cloud look like?
There I would delete points with "confident" 0-1 or 0-2.

General / Re: Why so many seamlines circles ?
« on: August 16, 2021, 04:22:25 PM »
You only see these seamlines when they are switched on.
Actually, they should not be a problem.
In my example it is clear that the crown of a tree is not perfectly reproduced by an image with oblique views.
If you don't like it, just draw a patch over it. (And assigns a new image as a link)
You will see the difference. (Or not)

General / Re: Why so many seamlines circles ?
« on: August 08, 2021, 12:05:44 PM »
Well, there will be something in it that " noises ", or varies in height.
You know that you can change and assign the lines manually?

General / Re: Merge classified dense cloud
« on: August 07, 2021, 09:59:18 AM »

General / Re: Placing markers increase camera erros after calibration
« on: July 23, 2021, 07:58:05 PM »
There are many sources of error...
Is the rolling shutter correction activated?

General / Re: Your opinion on USGS Agisoft Processing Workflow
« on: July 14, 2021, 11:50:12 PM »
I am especially interested in the discussion limiting keypoints and tiepoints - since as Paulo noted, that increases processing time substantially. I hope to get around to doing some experiments on that soon, but again I expect the results will be somewhat specific to different camera types.

Unfortunately, Agisoft's automatic limitation of tie points is a black box.
We don't know which "formulas" are used to reduce the points.
I only know that it works very well.
As already mentioned, it is certainly possible to get another millimetre out of it, but the effort for this increases a lot.
It is possible that metashape uses a different but similar algorithm to limit the tiepoint.

By the way, the hole workflow is similar to the one described here:

General / Re: Your opinion on USGS Agisoft Processing Workflow
« on: July 14, 2021, 10:01:36 AM »
For anyone using MS with aerial drone image sets, this is very interesting.  It all seems straight forward until you get to the the removal of points using gradual selection.  I did a quick test with the project I'm working on and if I follow the recipe, the values for photo errors go down but the error for the check points goes up. I'm talking very small movement, but movement in the wrong direction. Since my confidence is highest in the check point coordinates, I abandoned the idea of reducing sparse cloud points if the reported check point errors go up.

Perhaps I'm misunderstanding this "subjective step" (used in the latter USGS workflow) and that it's not really suitable for projects where in the end, I uncheck all of the photos (cameras) and use only the coordinates of the ground control points?

It would be great if you experienced guys would weigh in.


That is exactly what I have found.
I think it depends on the project you are working on. What camera and what altitude etc.
Metashape does a good job here "out-of-the-box".
However, turning off RTK coordinates altogether should not be the goal.

General / Re: Help with a mesh error
« on: July 13, 2021, 03:56:40 PM »
In a textured mesh, it is very difficult to see the errors.
Maybe you can show a picture without texture again?

To be honest, I don't really understand the procedure yet...
Are there deviations in the pure camera calibration / control points?
(Without a point cloud or an elevation map being calculated?).

General / Re: Your opinion on USGS Agisoft Processing Workflow
« on: July 06, 2021, 03:20:11 PM »
The procedure in the instructions is very interesting, and I had already tested it some time ago.
Unfortunately, I have to say that the effort is in no relation to the result.

I use levelled fixed points to check the accuracy. (+/- 1mm)
1.) If you calculate without a tie point limit, the calculation time increases immensely.
2.) Up to a certain point of the gradual selection I get nearly the same results as if I use the "normal" 40000/4000 values.
3.) But the worst thing is:
The more I do the "optimisation" after a certain point, the worse the control points fit!
It comes to a kind of overcorrection, which delivers worse results for me.

In the best case , I am 1mm better; but have a significantly longer calculation time.

General / Re: How to split huge projects?
« on: July 06, 2021, 11:52:14 AM »
I took another look at the python script (split chunks).

It actually works very well!
However, it creates a small "seam" at the edges that is somewhat "inaccurate".
At least the confidence is lower there.
It would be practical if you could set an overlap of approx. 1% when creating, and make it smaller by 1% again when merging.

I am also missing the confidence setting when creating the point cloud with the scipt.

Why I have not done the boundary via the "region" so far:
Sometimes it calculates only half or a very bad and inaccurate point cloud in the region.
If I make the region a little larger, it sometimes works or gets better.


But generally, does adding extra missions/flights/tracks/dives worth of data to any data set increase the Align Time exponentially???

That always depends on the overlap and other factors.
But 18.000 pictures is also a VERY big project. (I think)
By the way, it is not always helpful to use the "highest" presettings.
If you don't need centimetre precision, I think the very low settings are sufficient for alignment.

Did you start the alignment from the beginning each time?
Normally you only need to realign added photos.

Some of our projects also calculate days.
But if your computer occasionally crashes both with the dense point cloud and with DEM, you should look for another solution...


General / How to split huge projects?
« on: July 03, 2021, 09:58:32 AM »
How do you divide your projects in chunks? (and merge them at the end)
We have kilometres of thin geometry with round about 8000 pictures.

I've tried a few things, but I'm not sure I've reached the optimum yet.

The image alignment should, I think, run completely with all images in one chunk.  (For perfect bundle block adjustment)

If I now cut the thin point cloud hard in the middle, the edges of the dense point cloud become quite inaccurate.
You can NOT just make a cut in the middle, because then the edges of each part will get a bad confidence.
So you would have to cut with overlaps.

This makes it a bit more complicated when you join them together later.

Does anyone have a "nice" solution?

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