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Author Topic: Aligning single flight line, i.e. Pipe or road  (Read 4479 times)

masopiq

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Aligning single flight line, i.e. Pipe or road
« on: December 29, 2015, 12:47:13 PM »
Hi,
It is possible to process orthomosaic from single flight line photos (with 80% overlap), for example in pipeline monitoring or road mapping?

Thanks

Artisan S

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Re: Aligning single flight line, i.e. Pipe or road
« Reply #1 on: December 29, 2015, 02:05:33 PM »
Try it, in my experience yes, but it depends on the subjects you are shooting of course. If there is enough information in the various shots, why not.....more lines give more information of course but sometimes you have to make compromises and make do with what you've got.

Greets, Ed.

bigben

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Re: Aligning single flight line, i.e. Pipe or road
« Reply #2 on: December 30, 2015, 03:29:56 AM »
The biggest problem will be from drifting lens distortion parameters during optimisation.  If you have calibrated lens settings (or reuse lens settings from another project that aligned very well) then fixing the lens parameters will help avoid the usual problems with a single camera path

Artisan S

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Re: Aligning single flight line, i.e. Pipe or road
« Reply #3 on: December 31, 2015, 04:02:28 PM »
Agree, I have no such problems since I use (bought) a well known lens, camera combination, so it usually callibrated....also you I clean up the sparse point cloud in such cases....using this method:

https://dinosaurpalaeo.wordpress.com/2015/10/11/photogrammetry-tutorial-11-how-to-handle-a-project-in-agisoft-photoscan/

I can asure you, it works for me.

Greets, Ed.

Dave Martin

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Re: Aligning single flight line, i.e. Pipe or road
« Reply #4 on: December 31, 2015, 05:14:14 PM »
In addition to the advice above, I would suggest that you should have your photographs as accurately geo-tagged as possible; if possible synchronised positions with shutter-release, rather than just time-offsets.

Dave

Herman

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Re: Aligning single flight line, i.e. Pipe or road
« Reply #5 on: January 02, 2016, 08:30:43 PM »
Hi ,  I have done 50km single line images with 80% forward overlap, no problems just to produce a stitched mosaic.
I little more difficult when you want to do a accurate DTM & ortho.
What I have noticed is that if the width ratio to the length get lower than 20% then the processing struggles
What helps to improve the geometry is to fly the same area at two different heights
With the the single lines the original alignment sometimes gets twisted, before you do the the rest of the processing rotate the bounding box that the red bottom section is parallel to the surface if it is rotated
Regards
Herman