Messages

1

General / Tips and tricks for creating the highest quality/most efficient ortho image?

« on: June 27, 2023, 02:13:01 AM »

Im looking to create a new video on how to make the best possible ortho image from UAV photogrammetry, In terms of efficiency and quality.




I was hoping to get some input here from this fine community if anyone has any tips and tricks I can add to the list of parameters I am going to test.




I have an idea on what the answer is to most of the following questions but was hoping to get opinions of others, and then do some testing to hopefully get a somewhat definitive answer.




How much motion blur can you have before it affects quality? 2x GSD, 4x GSD?

At what point does shadowing become too significant an issue?

Does more overlap at a higher altitude help with stitching elevated objects such as powerlines and tall buildings?

Does more overlap improve quality? What is the minimum overlap required for a typical (non homogenous) area of interest?

Do obliques images help?

Does creating your DEM from depth makes make a difference?

Are there any processing settings that make a significant difference (blending mode, refine seamlines, hole filling, ghost filtering, ect)?

Can you create an acceptable ortho without any Nadir images?

What effect does changing your f-stop have? What is the best f-stop to use? And in what situation?

How much effect does changing your iso have? Can I get away with iso 200, 400 in low light conditions without significant quality loss?





If you can think of any other questions you'd like an answer to or to have some testing done, please add them here.

2

General / Re: How are you using the meshes you create?

« on: April 23, 2023, 12:43:10 AM »

Ok?

3

General / How are you using the meshes you create?

« on: April 22, 2023, 09:11:14 PM »

You've scanned a outdoor scene, processed the data, cleaned it, now what? How are you/your client finding value in that mesh? How are you/they using it?

4

General / Re: Problems exporting 3d models

« on: April 10, 2023, 04:15:56 PM »

Wouldn't any model that's georeferenced be far from the origin? What's the work around? Shift it in export then use it where needed then shift it back when you want it georeferenced again?

5

General / Best way to get a mesh into Autocad?

« on: April 10, 2023, 04:15:12 AM »

What is your workflow for getting georeferenced objects (parts of a mesh) out of Agisoft and into Autocad?

6

General / Cleaning your sparse cloud via gradual selection

« on: April 03, 2023, 06:41:33 AM »

I've been experimenting cleaning my sparse cloud with gradual selection using the techniques listed is the following USGS handbook (https://pubs.usgs.gov/of/2021/1039/ofr20211039.pdf)

However after significantly cleaning up the sparse cloud and removing a large number of bad points, once I create my dense cloud it is almost identical to the dense cloud I created by not cleaning the sparse cloud.

Has anyone else observed this? Is it a waste of time and effort to clean the sparse cloud?

7

General / Re: Techniques to clean your point cloud in Metashape

« on: March 29, 2023, 01:32:19 AM »

You may also be interested in looking at some workflow report:

https://pubs.usgs.gov/of/2021/1039/ofr20211039.pdf

Thank you very much for that, tons of good suggestions here.

8

General / Re: Techniques to clean your point cloud in Metashape

« on: March 27, 2023, 05:28:51 PM »

Thanks for the replies, anyone else?

9

General / Re: Techniques to clean your point cloud in Metashape

« on: March 26, 2023, 05:48:00 AM »

This is more of a general question and not project specific.

10

General / Techniques to clean your point cloud in Metashape

« on: March 26, 2023, 01:25:30 AM »

Im curious as what techniques is the community using to clean data inside of Agisoft?

So far im using;

• Filter by confidence
• Gradual Selection - Reprojection error
• Gradual Selection - Projection accuracy
• Gradual Selection - Reconstruction Uncertainty

Does anyone remove some photos via estimate image quality and pull out any below X value?

Any tips to generally improve my point cloud processing results that can be done in program?

11

General / Aligning photos, optimizing cameras and gcps - HELP PLEASE

« on: March 18, 2023, 05:02:29 AM »

I’m trying to run some tests on accuracy with X number of GCPs and seeing weird results.

100 acre sites. 16 GCPs set with rtk. 800 images taken with a M3E running rtk.

Test 1 - rtk only, gcps used as checks. An average error or 2cm hz and 2cm vert.

Then I did what I thought would negate the rtk positions of the images, i unchecked every box in the reference pane beside the images and picked my GCPs the way I normally would, optimized cameras with the images unchecked and the GCPs checked and reprocessed. I didn’t realign images, I was under the assumption that when I pressed optimize cameras based on the new settings it would not use the rtk positions anymore. I saw slightly better results, nothing unexpected yet. But as I ran the project over and over taking away gcps, reoptimizing and reprocessing I wasn’t losing as much accuracy as I thought. Even at 3 gcps only. So I realigned as well with 3 gcps set as control and the rest as check and still had only a few cm off error across the site.

Could the rtk positioning of the images be making its way into the processing results somehow and tightening everything up?

12

General / Re: Geoid Not Being Applied

« on: March 15, 2023, 05:44:34 PM »

Im running an older version that doesn't have that feature. I can make my own prj file and use that if I can see an example of how other prj files are loading their geoids. Does Agisoft store that information anywhere in the file structure where I can go and view it?

13

General / Geoid Not Being Applied

« on: March 14, 2023, 11:28:28 PM »

I have images that were captured in WGS84 (RTK) and I would like to convert them to NAD83 UTM11N with a CGVD23 (HTv2.0 Geoid).

When I choose convert to "NAD83(CSRS) / UTM zone 11N" I can see there is no vertical datum applied to that map projection. I have the option to convert to  "NAD83(CSRS) / UTM zone 11N + CGVD2013 height" but we don't really use CGVD2013 here.

I tried that option anyways knowing my local shift is 0.30m and it came it 0.60m out of position so something weird is going on there too.

I can shift my finished point cloud in NAD83(CSRS) / UTM zone 11N by the CGVD28 geoid separation in CloudCompare and it works out ok but its not really the right way to do it because I'm shifting ellipsoid elevations. On this site the geoid separation changes by about 30mm from one end to the other.

My current work around was to shift the CGVD2013 converted cloud. It's still not right but the best I have right now. The geoids match up relatively well over small areas.

Does anyone know how I can apply the Geoid I want to apply? I have it in my Geoid folder already, I just need to figure out how I can apply it. Ideally I could tell Agisoft that X geoid should belong to Y map projection.

14

General / Re: Laptop recomendations

« on: March 14, 2023, 01:05:54 AM »

With budgets being equal can someone build/buy a laptop that would be comparable to a desktop unit? If not, any idea what the loss in performance would be? 50%? 80%?

15

General / Importing RTK images

« on: March 12, 2023, 06:28:03 AM »

When I try to import images taken from my M3E that was capturing images in RTK mode it isn't importing camera location accuracy even though that box is checked in preferences.

Is there something I need to do to the images before importing them via Workflow > Add Folder ?