Recent Posts

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General / Re: Mavic 3E and Trimble X7 Alignment
« Last post by Paulo on May 23, 2023, 07:19:37 PM »
My suggestion would be extract foto identifiable GCPS from your laser scan survey and use them to reference the Mavic3 chunk and then merge laser scan and drone chunk....

My worry is why you get 40 mm error on GCPs on your drone Survey done at 7 m distance from building. This would give you around 2 mm GSD and a correct alignment/modelling should give errors around 2 to 4 mm not 40!

General / Re: Mavic 3E and Trimble X7 Alignment
« Last post by harrytwomey on May 23, 2023, 06:10:47 PM »
Hello, and thank for the response

I see what you mean, I have been working with a limited set of my data for speed, to find something that works

What I actually have is a fully laser scanned building, about 700 scans, but I will limit to just the external that is closest to the facade of the building, which will be around 130 scan

We did a standard topographical flight and built an initial model and used the flight planner to make a path for the Mavik to fly at 7m distance from the building with the intention of making a high-detail model.
We have that processed ok, 3500 photos @ 24GB of imagery, but there are still some areas where the drone could get into, see Picture 1 below(shows bad matches I currently have)

the mavik dataset alone was off 40mm for GCP, whereas my Laserscanner is good to 5mm, so I want to learn how to get the Pictures to align to the Geofrenced Laser Scans, for this and future projects
General / Re: Combining laser scans, terrestial images and drone images
« Last post by Dieter on May 23, 2023, 05:03:46 PM »
Alignment between laser scans and photos is difficult to achieve. The distance and angle to the object must be almost identical, then it works well.
In addition, since version 2.0 there have been problems with the alignment of photos and scans in Metashape, so we are trying to prevent this.

For years we have been generating building measurements according to the following workflow:

1) Glue control points in the windows, which are visible from inside and outside.

2) Fly over the facade with a PPK drone and, if necessary, align it with photos taken by hand in Metashape.

3) Scan the interior and link it to the exterior facade using the coordinates of the control points in the windows.

Point 3 is not carried out in Metashape, but in a special scan program. The point clouds from the two programs can then be merged and processed further.

Hope that helps,

General / Re: Dense cloud wall surface covered by dupliacted, poor cloud
« Last post by Dieter on May 23, 2023, 04:46:08 PM »
I'm downloading it, it's taking time...

What I can already say: 1/30 shutter speed is not enough for interval recording. Half of the images are blurred. I fly without an interval and have a shutter speed of at least 1/100, preferably 1/200 if possible. I set ISO to AUTO.

I (and Metashape too) prefer noisy images to shaky ones.

General / Re: Mavic 3E and Trimble X7 Alignment
« Last post by Dieter on May 23, 2023, 04:38:44 PM »
In my experience, the scan point of view has to be roughly identical to the drone point of view for identical points to be found at all, with colored point clouds working better than grayscale scans. In your example, that's not the case at all. Metashape does not compare the point clouds, but the panorama image, and that should be almost identical to the drone images.

It is irrelevant which model the drone is.

General / Re: How to use keyboard to rotate model ?
« Last post by NikosMavronichtis on May 23, 2023, 02:21:48 PM »
ok Thanks!
General / Re: How to use keyboard to rotate model ?
« Last post by tazzo on May 23, 2023, 02:19:28 PM »
I think you have to fine adjust with the trackball
General / Mavic 3E and Trimble X7 Alignment
« Last post by harrytwomey on May 23, 2023, 02:07:15 PM »

I'm having huge issues with this workflow,

I have followed the Tutorials and every conceivable combination, but either my scan data which is georeferenced in Trimble Realwork, get moved in crazy location with my drones sparse cloud (laser scan group rest alignment[N/A]), or does not find any matches with the point cloud in the fixed position [R]

Does the E57 you using need to be a coloured point cloud to work?
I tried PTX and PTS with no improvement

My Pointcloud are greyscale intensity and I am only getting 22 match, at most between the scan data and the photos
also, some of the matches are very wrong

When I Import Laser scans there position/rotation (From Origin on import) is in the estimated area? I tried "From Unknown" on import also.

I tried Importing them in the Coordinate system of the photos and local coordinates

I tried all the above multiple times in 2.0.15, 2.0.16 and 2.0.2 with no improvement

I also tried using the layout script but this didn't seem to have any effect.

Attached Picture 1 shows the Low match count,
Attached Picture 2 shows Bad matches and also Valid matches which I would say are incorrect
Attached Picture 3 shows LASER SCAN GROUP being rotated out of position

There seem to be a lot of people here with Mavic 3E, maybe would use laser scan data also, could I DM someone for help
Camera Calibration / Drone images during light changing conditions
« Last post by michaldolnik on May 23, 2023, 02:00:30 PM »

We have noticed problems with outputs of multispectral maps, when images were taken during the light changing conditions.

The other softwares - Pix4D did much better.

Do you have some experience how to solve it?
General / Combining laser scans, terrestial images and drone images
« Last post by NikosMavronichtis on May 23, 2023, 12:55:33 PM »

I am looking for the most efficient workflow in order to use laser scans files (structured form e57), images from a FF camera with a good wide lens (20mm) and images from an RTK drone (Mavic 3E)  for medium scale buildings.
No GCP will be used, georeferencing is not important.
Texture quality is very important.

I have read the tutorials:

and have experimented on their combination, but I mostly have difficulties in alignment.

What I think best after proper alignment is meshing from the laser scan point cloud (for the interior areas) and drone (for roof ares), texturing from the images of FF camera (for facades) and drone (for roofs only).

I would like your help in the steps I should follow and any tips for this complex integration in terms of alignment, meshing and texturing parameters as no tutorial is available so far for this case.

Thank you in advance!
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