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Messages - airmap3d

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46
General / Re: Report values
« on: July 03, 2013, 12:07:19 PM »
That is actually a very good question.  I've never really paid that much attention but I have just run some basic calcs on my reports and nothing seems to add up?

Anyone got any ideas?

47
General / Re: Power lines and suspended objects??
« on: July 03, 2013, 11:39:40 AM »
Hi Porly,

Thanks for the reply.  That model was actually built in high setting.  I have tried all of the others also (apart from ultra) and they all do a similar thing.

Your other option is a good one though, I will give that a go.  Could be an issue for powerlines though as they will span over numerous photos?  Luckily my business is based around mapping the bare earth, otherwise I may have been in trouble!

Thanks.

48
General / Re: Align photos
« on: July 03, 2013, 11:31:27 AM »
Hi Peter,

From what I can see the visual quality of the ortho doesn't really seem to be all that much better, if at all, when produced from a higher setting.  Although I haven't checked the geo-accuracy??

And yes, the sparse point cloud will be much larger when 'high' setting is selected.  If you are only interested in the ortho then you may be able to get away with aligning photos on low but if you are also requiring a point cloud to accurately represent the terrain you should definitely run it on high.

It does take a long time, especially with large amounts of images but that can be easily decreased by investing in some high end computer hardware.  The CPU's are dealing with Gb's of data so to a certain degree, you just have to be patient.  I would recommend dual xeon processors, good ones, if you don't already have that. 

49
General / Power lines and suspended objects??
« on: July 03, 2013, 05:41:18 AM »
Question...

Does anyone know how to create accurate orthos of suspended objects, such as power lines etc?  Generally anything suspended above the ground comes out very segmented.

I understand the fundamentals of aerial photogrammetry and why this is an issue but is there a way that Photoscan can potentially correct these problems?

I am doubting that there is but just thought it was worth asking.

See attached image for an example.

Cheers.

50
General / Re: Geometry type requirement for 2D orthomosaic
« on: July 03, 2013, 05:05:20 AM »
I perform UAV mapping over various terrain types and have just run some tests creating orthos from different 'build geometry' setting.  Point cloud vs meduim (smooth) vs high (smooth) produced very similar results.

Personally, I just use point cloud geometry type to extract my orthos as the time involved to build higher quality geometry doesn't seem to yield any significantly better results.

But as RalfH stated, always best to test for yourself as every ones situation is different.

51
General / Re: Hardware request of information
« on: June 30, 2013, 05:49:43 AM »
Hi Marek and/or Mohabon,

What sort of accuracy are you requiring with your work? xyz?

I do very similar work to what you are intending on doing in here in Australia and can possibly give you a little insight into the process...

From my experience, 'build geometry' isn't even needed to produce an accurate DEM from a UAV of your specifications.  The sparse point cloud over an area of 50ha can give you up to 2-4 million points.  This is more than enough to produce an accurate surface model.

I achieve absolute accuracy's in the order of +-100mm in the vertical (often better) and always better in the xy.  You will need some other point cloud editing software to produce a 'bare earth' model though.

Hope this helps.

52
General / Re: Gradual selection???
« on: June 29, 2013, 04:43:35 PM »
Hi Alexey and Porly,

Thanks for the replies, very much appreciated.

It's all slowly starting to make sense.  Now to go and put it into practice...

Thanks.

53
General / Gradual selection???
« on: June 29, 2013, 03:37:55 PM »
Hello all,

I have asked this question before but sadly got no replies!  Maybe it's a tough one?  I'll try again...

Reprojection Error and Reconstruction Uncertainty... what exactly do they mean?  And what are the numbers on the slider bars representing?

I have basically worked out what I need to be doing with them to get good results but I don't actually understand the principle behind what I am doing!?!

ANY thoughts towards this topic would be very much appreciated!!

Thanks.

54
General / Re: Strange workstations testing results.
« on: June 24, 2013, 03:45:05 PM »
Yep, same data. It was about 500 images so was a reasonable sized job.

This thread seems to be getting some very mixed results! All very confusing!!

55
General / Re: Strange workstations testing results.
« on: June 23, 2013, 04:32:38 PM »
Hello all,

I have just run a test on my machine and have come up with the following...

I used a large project of mine and tested align photos with hyper threading both on and off.  I am running windows 7 pro with dual xeon E5620's, Photoscan Pro 0.9.0 (1586) and it was 20% faster with hyper threading enabled.

I will continue to use PS with HT enabled but from what I can gather from all of this is that every machine and config is going to be different so I would suggest testing your system and running with what works best for you??  Seems a simple solution to me.

Cheers!!

56
General / Re: Apple Mac running Windows 7?
« on: May 24, 2013, 02:52:45 PM »
Thanks Wishgranter.

57
General / Apple Mac running Windows 7?
« on: May 24, 2013, 02:27:02 PM »
Hello all,

I have been offered the use of a Mac Pro which is running Windows 7.  Will Photoscan Pro work on this computer or will it only work on an actual PC?

Cheers,
Matt.

58
General / Re: Does the 'Align Photos' stage utilize the GPU??
« on: May 05, 2013, 02:59:32 PM »
Thanks Alexey :D

59
General / Does the 'Align Photos' stage utilize the GPU??
« on: May 05, 2013, 02:40:16 PM »
Hi all,

Can anyone tell me if the 'Align Photos' step uses the GPU at all or is it only using the CPU during this stage?

Thanks.

60
General / Gradual selection - need a simple definition
« on: April 27, 2013, 07:30:09 AM »
Hello all,

I am struggling to understand the principles behind the 2 options available within Gradual Selection, specifically in point cloud mode.

I have read what manual has to say about it but still don't fully understand.  I process aerial imagery of areas up to 50ha from a UAV, mines and quarries mainly, and believe that this process is going to be important to me in achieving the best results.

Can someone possibly explain these features in 'very basic' language to me and perhaps even suggest what settings I should follow to remove erroneous points etc? 

What exactly do the numbers on the scale bars mean when performing both Reprojection Error and Reconstruction Uncertainty?  Reprojection Error I am guessing is a distance in metres?

Any explanation would be much appreciated!

Many thanks,
Matt.

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