Agisoft Metashape

Agisoft Metashape => General => Topic started by: GeoGecco on February 22, 2018, 05:27:51 PM

Title: Orthomosaic deformation of images
Post by: GeoGecco on February 22, 2018, 05:27:51 PM

Dear Team,

when I want to generate an orthomosiac sometimes I'm using the Mesh generated from the Dense Cloud but sometimes I'm also using just a flat plane (a big plane importet from a different software with only 2 big faces). This helps me to project the images on to a flat plane.

Now my problem is that the images projected onto a flat plane are somehow bended.
See image below:


Why do they bend? Can I somehow prevent that effect? I only want to have the effect of radial distortion in it. it seems that there are more effects.

EDIT: It doesn't matter which image I choose using "replace image" via the selection. They are all bended

Title: Re: Orthomosaic deformation of images
Post by: stihl on February 22, 2018, 07:28:35 PM

Seems to me like an alignment issue.

If the cameras that cover this region are not properly aligned, they will cause a displacement in the Orthomosaic because the positioning and or orientation of those cameras is 'off' compared to the flat plane.

Title: Re: Orthomosaic deformation of images
Post by: GeoGecco on February 23, 2018, 10:50:24 AM

Thanks for the reply. They are pretty good aligned using GCP's with an accuracy of 3 mm  GSD.
Even when they are missaligned the images would be projected using 6 parameter transformation. This usually never adjusts parts of the image in different directions.
Is it possible that the rolling shutter compensation has something todo with this?
The images itself look straight though.

Title: Re: Orthomosaic deformation of images
Post by: GeoGecco on February 28, 2018, 11:54:12 AM

Hi Alexey,

could you give me a quick answer to my question please?
This is something we need to solve.
It seems that the whole image looks like the residual plot of the lense.

Can I somehow just use a 6 parameter transformation onto a flat plane?