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Messages - Costas

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1
General / Re: Question about Orthophoto Resolution
« on: March 11, 2021, 03:10:24 PM »
The Orthophoto resolution is tied with the GSD and the camera parameters (focal length etc).

Bigger GSD results in lower spatial resolution (less detail).
Lower GSD = better spatial resolution (more detail).

GSD is the Ground Sampling Distance (distance between two consecutive pixel centers measured on the ground) and is related on the altitude.


Thus if you need better resolution on the Orthophoto you can do 2 things.
1) If you cannot change the Focal Length then the only option is to -> Fly lower
2) If you have the option to change the Focal Length on the camera then you can fly at the same altitude and decrease the GSD by Increasing the Focal Length.
3) Have a better camera.


2
General / Re: Using GCPs causes alignment problems
« on: March 08, 2021, 02:45:07 PM »
Hello dyoung,

The process should be:

1) Align Cameras
2) Import GCPs
3) After the above "Uncheck All Cameras"
4) Optimize Cameras.
5) Continue with all other steps for Dense Cloud, Mesh, etc as needed.

3
General / Re: Automated mission planning
« on: March 03, 2021, 12:08:05 PM »

For Phantom 4 RTK it is recommended to use DJI Pilot for Android (tested, works fine).

Is it working 100% with all RTK features (NTRIP corrections etc)? OR it works but like a normal non RTK drone?

4
General / Re: Automated mission planning
« on: March 01, 2021, 04:07:51 PM »
It seems the solution is to use the SDK version remote controller for Phantom 4 RTK witch allows to run programs such as Litchi on a screen of your choice (e.g. Mobile phone, Tablet, Android & Apple).

On top of that i see that your .kml has more than 99 waypoints. DJI do not allow more than 99 waypoints in 3rd party apps afaik.

note: Even if you have the SDK version i am not sure that Litchi or other apps work with NTRIP for RTK corrections etc.

5
General / Re: How does Assign Images works ?
« on: March 01, 2021, 03:20:45 PM »
Hello Robert1968,

I'm not an expert in this matter (i may be wrong) but i only use this feature if i need to remove an object from an Orthomosaic or if i want to make some blurry areas in Orthomosaics more clear by selecting a better image.

From what i understand the only difference between "Draw Polygon" and "Draw Patch" is that the second automatically chooses the best fit picture. Essentially you may only save a few clicks and time when you have a lot of editing to do.


To summarize:

Lets say that you have to do 20 edits in a big Orthomosaic.

Method A
Draw Polygon --> Assign image. (you do this for every polygon you create)

Method B
Draw Patch and see the result. Only if not happy with the result, right click and Assign an image you like. (No need to draw another simple polygon.)

I personally mostly use the second method because sometimes it saves me time when i have a lot of editing to do.

6
General / Re: Help Improving smooth white object models
« on: February 25, 2021, 02:32:21 PM »
From the pictures you posted i see that the most part of the surface is a bit shiny and it lacks distinct features on the surface because it is all white.

Because of the uniform color around the object there are not many features for the program to reconstruct the object correctly.

You can find many info in the internet on how you can "prepare" your object prior to shooting. I'll give 2 links with some info to start.
https://www.instructables.com/Shooting-for-Photogrammetry/#step2:~:text=If%20your%20object%20doesn't%20have%20a%20lot%20of%20surface%20detail%3A
https://www.3dscanstore.com/blog/3d-scanning-reflective-objects#content:~:text=Prepare%20the%20surface%20for%20scanning

I hope these will help.

7
Python and Java API / Re: List of Tweaks ?
« on: February 23, 2021, 01:17:44 PM »
Hello Alexey,

I still got the error when trying to set BuildDenseCloud/max_neighbors in v.1.7.0.

Today i updated to v.1.7.1 and the previous "main/dense_cloud_max_neighbors" was transofrmed automatically to BuildDenseCloud/max_neighbors  ;D

I have one question though.

I set Dense Cloud max neighbors = 850 (as i had similar problems sometimes with this post https://www.agisoft.com/forum/index.php?topic=11558.0).

The questions is what value should i set for Depth Maps max neighbors? I now have BuildDepthMaps/pm_max_neighbors=850.
Is there any correlation between values in Dense cloud max neighbors and Depth Maps max neighbors? Should they be the same, or half, or double etc? What is the best practice to set these values?

8
General / Re: How does Assign Images works ?
« on: February 23, 2021, 11:37:20 AM »
Hello PROBERT1968,

Using "Draw Polygon" and/or "Draw Patch" is essentially the same. There is only a slight difference. In "Draw Patch" the best fit image will be applied automatically.
Note: You can still choose to assign a different picture than the "best fit".

Description from the Help Documentation:

"If the Assign image operation should be repeated several times, it is recommended to use  Draw Patch tool available from the Ortho menu or with a corresponding Toolbar button of the Ortho view menu. In this case it will still be required to draw polygons as in the procedure above, but the best fit image will be assigned automatically, being selected with respect to the first drawn vertex of the patch."

In any case after assigning the photos you want, always remember to use the "Update Orthomosaic".

9
Python and Java API / Re: List of Tweaks ?
« on: February 13, 2021, 12:49:39 PM »
I'm a little confused Alexey.

I'm using Agisoft Photogrammetric Kit for Topcon v.1.7.0

I can set main/dense_cloud_max_neighbors = 850 but if i try to set the parameter for the NEW depth maps in version 1.7 as you said to BuildDepthMaps/pm_max_neighbors i get an error that "this parameter is not found"

Why is that?

Is my program using the OLD or the NEW depth maps?

If it indeed still uses the NEW depth maps is the main/dense_cloud_max_neighbors tweak working for me?

10
General / Re: Contour lines and false colour to show depth
« on: February 03, 2021, 11:06:10 AM »
It is possible to generate Contour Lines within Metashape.

1) Right click on the generated DEM and choose "Generate Contours"
2) On the pop-up menu choose your settings.


11
General / Re: dense cloud classification of ground/non ground points
« on: January 25, 2021, 02:53:01 PM »
After classification did you change the view so you can see the classification? (pic1)

You can also "filter by class" (pic2) to see only the classes you need.


12
Calculations take place for everything that is inside the Region Box. Thus by scaling and moving the Region Box you can limit the area of the calculations.

In your example you can:

1) Run initial alignment (High)
2) Scale and move the Region Box to the area you want. eg. so only the building is inside the box.
3) Continue to other steps to calculate Dense Cloud, 3D Model etc.

you can find the Region Box in the toolbar (photo attached)

13
General / Re: Orthomosaic without retangule backgroud
« on: October 22, 2020, 01:21:25 PM »
When you are on the "Export Orthomosaic" dialog you must check the last option called "Write Alpha Channel".

This will add transparency to the .gif file and thus you will get rid the white background.

14
Feature Requests / Re: Possibility to create TIN model
« on: October 20, 2020, 01:59:53 PM »
Hello Alexey,

The program i wanted to import the .dxf into is called "Tessera" by a Greek company (Anadelta) thus it is not very common and known. I use it for Road & Railway design & construction.

Exporting 3D model as "3D faces .dxf" worked fine for my project.

Thank you for your answer.


15
Feature Requests / Possibility to create TIN model
« on: October 13, 2020, 02:25:11 PM »
It would be nice to have the option to create a TIN model and export it as .dxf for use in other programs.

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