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Messages - Porly

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1
General / Re: Agisoft PhotoScan 1.2.0 pre-release
« on: October 19, 2015, 03:56:09 PM »
Hello,

I have some questions dealing with (new) parameters in PhotoScan 1.2.0

In optimize camera alignment dialog there is p3 and p4. Are these parameters additional terms (likep1 and p2) to create an aproximated function that describes the nonsymetric distortion function?

The other thing is fit aspect (before 1.2.0). What happens if its checked or not? Is it the aspect ratio between pixel in x direction an y? My idea was that optimzing this parameter forces the adjustment to create square pixels? I havent found anything in the manual...

Gradual selection:
What does projection accuracy mean?

Any help and advice is welcome!

Thanks

Paul

2
General / Re: Agisoft PhotoScan 1.2.0 pre-release
« on: August 07, 2015, 10:41:05 PM »
Please find attached the white gaps during seam line editing.

I have noticed that this happens only in noisy regions where terrain normals dont seem to match with image orientation.

@ Patribus: The used model is watertight closed, no gaps.

Thanks

Paul

3
General / Re: Agisoft PhotoScan 1.2.0 pre-release
« on: August 07, 2015, 10:28:38 PM »
Hello Alexey,

please find the attached the situation that caused a crash. Note that all input images are geotagged (Orthomosaic is rectyfied and scaled +-10m).

4
General / Re: Agisoft PhotoScan 1.2.0 pre-release
« on: August 07, 2015, 07:47:24 PM »
Hello,

great work Agisoft Team, a milestone for Photoscan!!!

I have noticed that theres is a problem with Export orthophotos (Tools --> Export --> Export Orthophotos). This function causes Photoscan crash.

One question regarding to seamline editing:

If I choose one Photo to assign to created polygon, some small areas are not covered (white gaps) even if the choosen photo contains texture informations of these gaps.

Thanks a lot!

Paul

5
General / Re: optimize camera alignment
« on: May 12, 2015, 07:14:05 PM »
Hello,

k4 should be checked for extrem wide angle or/and fisheye lenses.


6
General / Re: Agisoft PhotoScan 1.1.0 pre-release
« on: September 22, 2014, 04:19:53 PM »
Hello Dmitry,

great work!

Are there any new options, features or improvements for orthophoto generation? Is this changelog the final version until the official release or may some features be added in the new future?

To be honest I hoped there would be some new tools like seamline editing or something like that, to improve the workflow and quality for orthophotos.


 

7
General / Re: Ground Control Error Reporting
« on: August 06, 2014, 05:05:25 PM »
Me too

8
General / Re: Ground Control Error Reporting
« on: August 06, 2014, 04:13:13 PM »
Hello,

root ( (sum v^2)/(n))

should work like this.

where
v = estimated - input data (estimated error)
n= number of GCP

the 3D error (5th column) for each point is the spatial pythagoras.
root (dx^2+dy^2+dz^2) = 3D error

BR

Paul



9
General / Re: Worse sparse cloud with higher aligment setting.
« on: June 13, 2014, 02:26:43 PM »
Hello,

I had data sets where the alignment with 40k points was not succesful (cameras were not aligned), while with 20k the orientation of cameras was solved. In both situation the maximum set points were found. So with 40k, in each photo 40k points were detected. For 20k, it was 20k as well.

As I already said, the reliability of matches between photos in case of 20k could be higher, so that a threshold value between valid/invalid matches in case of lower amount of points could cause a more robust solution. There are always many missmatches recognized as valid in datasets with poor lightning/quality (noise), so that I can imagine, in case of 20k points per photo, more matches with a better reliability are prefered/used. In case of 40k there could be the same matches, but additionally some of lower quality that could falsify the results.

Thats only my opinion, I found it strange too as I saw better results with lower points. So I thought about it, and thats what makes sense for me.

Unfortunately I am on vacation right now, so that I cant search for a example data set. But when I come back I will try to prepare it for you.


10
General / Re: Worse sparse cloud with higher aligment setting.
« on: June 12, 2014, 02:47:25 PM »
Hello,

Accuracy
Higher accuracy setting helps to obtain more accurate camera position estimates. Lower accuracy
setting can be used to get the rough camera positions in a shorter period of time.While at High accuracy
setting the software works with original photos as are, Medium setting cause image reduction by factor
of 4, and at Low accuracy source files are reduced by 4 times more.

This is from the user manual, so marcel was right with his theory!

So that the input data is downscaled, and less number of keypoints are used, what causes exactly the things that marcel mentioned. Blurry photos downscaled are sharper.

But in my case using 20k instead of 40k (point limit custom setting) always gives a better result (with "poor" light/image quality) of camera orientation without downscaling the input data (both are on high).

Cheers

Paul

11
General / Re: Worse sparse cloud with higher aligment setting.
« on: June 12, 2014, 02:31:58 PM »
You are right, James! Just tried to start align photos on point limit = 2000 @ high, what causes 2000 point per photo. Point limit 2000 on low caused 2000 per photo too.

So looks like there is as fix min/max. value of interest points depending on the set point limit. But I dont believe that the fotos are downscaled... good, maybe I am wrong ;)

12
General / Re: Worse sparse cloud with higher aligment setting.
« on: June 12, 2014, 02:30:56 PM »
You are right, James! Just tried to start align photos on point limit = 2000 @ high, what causes 2000 point per photo. Custom 2000 on low caused 2000 per photo too.

So looks like there is as fix min/max. value of interest points depending on the set point limit. But I dont believe that there fotos are downscaled... good, maybe I am wrong ;) 

13
General / Re: Worse sparse cloud with higher aligment setting.
« on: June 12, 2014, 01:57:02 PM »
Quote
As far as I know the quality setting in the Align dialog sets the downscaling on the source photos before extracting points. When set to High, it uses the photos at original resolution, at Medium it downscales them to 50% size,  and at Low to 25% size.

The reason you get bad results at High is probably because your photos are not completely sharp, so Photoscan has trouble finding good points.
When you set the quality to Low, the source photos are downscaled to 25% of its original size, which means even a photo with a slight blur will be super sharp. So the downscaling improves the quality of your photos, leading to a more accurate Alignment.

While this may help, it's always better to have good source photos. Take a look at your photo at the pixel level (especially in the corners) to see if they are sharp enough. If they are blurry, moved or noisy then you need to work on your capture technique

Hello marcel,

downscaling the source photo is used for quality setting in the dense image process (build dense point cloud). In the alignment step, only the amount of interest points will be reduced, depending on the quality setting. High=40000 (with default setting) Low~4000. You can follow this in the console during "detecting points".

14
General / Re: How far can a GoPro go...
« on: June 12, 2014, 01:46:23 PM »
There is no other light camera that is compatible with the 2/3 axis Gimbal, as far as I know. With the Gimbal you have already a Plug n Play FPV Port that works with the Phantom 2 in combination with the GoPro.

Of course the price Lens+GoPro is comparable with a DSLR or DSML camera, but they are too heavy ;)

By the way a gimbal for the nex 5 costs ~1500€ ;)

I have already seen setups with cheaper compact cameras (bigger sensor), but there were used without gimbal. FPV is not so easy to realize with each camera model. Also the simple option of continuos shoot of photos.

(german)
http://www.kopterforum.de/topic/5625-dji-phantom-und-sony-rx100/

I am not an expert in these things, but there people using a sony rx 100 with the phantom 2. Maybe there is a custom way to make it FPV ready, I dont know. But it will not be easy. There is no official Gimbal for these cameras.

15
General / Re: Worse sparse cloud with higher aligment setting.
« on: June 11, 2014, 11:46:07 PM »
Hello,

yes it is possible. For Aerial imagery I am using 40k keypoints per photo, for terrestial with poor light conditions I always gain better results with 20k points per photo.

Seems like in case of lower amount of points Photoscan use points or matches of higher precision (lower variance or higher interest value, better reliability). The lower amount of points causes more robust results in "poor" quality input data.

Cheers

Paul


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