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Author Topic: Wavy trees and errors ob building edges  (Read 5046 times)

Santiago

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Wavy trees and errors ob building edges
« on: June 11, 2013, 06:28:49 AM »
Hi everyone,

I was wondering how could one avoid this mistakes on the orthomosaic and is everyone getting this kind of mistakes always, or are you getting true orthomosaics with perfect quality.

What are the causes of this mistakes? Incorrect camera parameters? Poor overlap? Altitude of the flight? Type of lens used?

Thanks for any help and guidance you guys can give me and many others who I'm sure face this same issues.

Best regards,

Santiago


Herman

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Re: Wavy trees and errors ob building edges
« Reply #1 on: June 14, 2013, 09:27:12 AM »
Hi Santiago

The buildings I am sure is caused by relief distortion and the tress by a mixture of movement between successive pictures and relief distortion.  This together with the poor blending between tiles (the 2GB limit of  the ortho photo tiles) unfortunately make a good product look very poor sometimes.
I have noticed that some more GCP around such features helps a litlle bit.
Regards
Herman

Santiago

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Re: Wavy trees and errors ob building edges
« Reply #2 on: June 19, 2013, 01:54:23 AM »
Hi Herman,

Thanks for your reply. So you say the building edge issue is because of relief distortion. For what I understand about relief distortion, is that's one kind of geometric distortion that occurs for taller objects that are further away from the center of the picture, but in this case that building is in an image that contains the whole building pretty much in the center of the picture. But if it was certainly caused by relief distortion what can I do to correct this issue, because I would most likely love to present an excellent final result to my clients. I attach the image where the building is contained almost in the middle.

When you say movement between pictures in the vegetation issues. Do you mean like movement of the UAV that causes blurry or tilted pictures or what do you mean exactly?

One thing I forgot to say is that I dind't use any GCP's, I'll use some next time to see if there are any improvements.

I would love to see some good results any of the users of Agisoft have of building edges, just so I know it can actually be achieved without any mosaic editing tools, or if i'm just expecting something not yet possible.

Best regards to all and thanks Herman,