Messages

1

Feature Requests / Re: Iterative Closest Point Algorithm

« on: April 16, 2020, 10:05:39 AM »

Hi Stephan,

have you ever tried that? And does it work?

I am willing to try it myself but I would like to have some feedback from the members of this community.
Even better if someone could share the script but I guess that might be confidential...

Regards,

2

General / Re: Workflow with calibrated camera

« on: June 03, 2015, 07:43:37 AM »

Hi Bigben and Nadar...
sorry for the delay but I was traveling back from United States to Australia...

If you are sure about the values of your internal orientation (i.e. the camera calibration parameters), I think you should rather keep these fixed and leave the program play only with external orientation. You may obtain worse results in terms of residuals, but will not introduce "strange" camera geometry.
Moreover, I found sometimes problems processing multiple chunks acquired with the same camera: optimised camera calibration parameters are not exactly the same, and I guess this is not good for chunk alignment.

I think this is exactly the point!
Especially for my study case...
I`m trying to build a 3D model of both rims of a 500 meters deep gorge.
I have camera position locations and GCP right to the edge, but nothing (obviously) on the rockwall.
So if I let Photoscan optimize my pointcloud adjusting camera parameters I could affect it with undesired distortions...
More over, aligning different chunks together could introduce even other problems.
The precision of my coordinates has cm accuracy but I already checked and Photoscan doesn`t seem to change them too much.

I didn't know there was a "sensibility" function in Photoscan.
Would be interesting to get new help by somebody else who`s already used it in the past...

P.S.: I`m gonna show you few screenshots of my final models when I`ll finish aligning and process them.
Thanks

Davide

3

General / Re: Workflow with calibrated camera

« on: May 23, 2015, 06:43:06 AM »

Any new suggestion??
Come on guys...
I`d like to discuss with ones of you who have already experience in surveys using a calibrated system (procedure a bit different from usual Agisoft tutorials...).
Thank you!

4

General / Re: Workflow with calibrated camera

« on: May 21, 2015, 02:20:38 AM »

Hi Nadar...
I did a bit of research before converting my camera parameters from Photomodeler to .xml (Photoscan).

According to this post (http://www.agisoft.com/forum/index.php?topic=2673.0) shouldn`t be so difficult.

Furthermore it was just Alexey to provide the answer...

You can use Convert option in Agisoft Lens tools menu.

In the opened dialog choose Photomodeler Type and then input all parameters manually according to the calibration results in the units specified in the dialog. Then click OK and you'll get the calibration report that you can export in PhotoScan XML format.

That`s exactly the procedure I followed...

Hopefully it`s correct.

So these questions are still to be answered:

 

What happens if I would optimize my point cloud using fix precalibrated option anf GCP coordinates (accuracy within 2cm)?
Does Agisoft change always camera positions coordinates or even GCP ones?
Shall I untick probably the precalibrated configuration and using only GCP coordinates?
How shall I use gradual selection to delete wrong points?
Usually I used just reprojection error set at 1 and then optimized my point cloud until in "show info" my chunck appears having reprojection errors smaller than 1...
Thanks for your help!

Thanks for any help!

Davide

5

General / Re: Workflow with calibrated camera

« on: May 20, 2015, 04:39:20 AM »

Hi bigben and thank you for your visit!
I just checked that yesterday night...
I think I`m gonna optimize my point cloud not adjusting camera/lens parameters but only changing camera position/orientation.
I guess my calibration file is pretty consistent and accurate (even I used different focus distances from calibration project). Camera positions on the contrary could be wrong of 10/15cm sometimes...
What happens if I would optimize my point cloud using fix precalibrated option anf GCP coordinates (accuracy within 2cm)?
Does Agisoft change always camera positions coordinates or even GCP ones?
Shall I untick probably the precalibrated configuration and using only GCP coordinates?
How shall I use gradual selection to delete wrong points?
Usually I used just reprojection error set at 1 and then optimized my point cloud until in "show info" my chunck appears having reprojection errors smaller than 1...
Thanks for your help!
Davide

6

General / Re: Workflow with calibrated camera

« on: May 19, 2015, 03:42:37 AM »

Thanks nadar for your reply!

I have calibrated my fix 35mm lens using Photomodeler and a 3x3 grid of paper sheets with 5 coded targets on each (total of 45).
Camera was set on autofocus.
Distance between me and target around 3 meters.
Pictures were taken from 4 positions around targets, 3 pictures from every position (2 portrait and 1 landscape).

Field work condition right now: rockwall far 450 meters from me.
Same camera and lens but different focus distance (AF set).
Coordinates of camera stations known, GCP on the other side of the gorge visible and known.

Workflow in Photoscan:
Align pictures using reference mode and precalibrated  configuration (not fixed).
In this way align over 200 images is pretty quick.
After that I`m gonna optimize the pointcloud based on GCP coordinates.

My question is: which camera parameters should I optimized if my camera is already calibrated?
Should I do it, since my calibration site and fieldwork site are pretty different?
If I fix the calibration file in Photoscan, is not possible to optimize the pointcloud (camera parameters are untouchable)...
So how do you do that?

I`m looking for suggestions to run out this project using this data and to understand how perform other similar projects in the future without necessarily the need of recording GCP on the ground (long range ground based photogrammetry or aerial photogrammetry).

Thanks to all

7

General / Workflow with calibrated camera

« on: May 16, 2015, 05:26:41 AM »

Good day!
I`m mapping geological features called breccia pipes in Arizona along a huge gorge.
It`s gonna be a massive project (almost 1000 pictures from ground based camera stations)...

I`m using a Canon 500D plus a 35mm lens calibrated in Photomodeler using a grid of 9 sheets and coded target printed on them (calibration seems be pretty consistent according to the report).

For every camera position have been recorded coordinates on the ground using a DGPS in RTK mode (offset in altitude has been measured with a roll meter).
I drove on the other side of the Gorge to put several GCP, surveyed always with DGPS.

I  tried to process quickly just a few pictures to see which results could be achieved but I got a bit confused.
I noticed that reprojection error is surprisingly high...
I usually import my pictures, my calibration file (correctly converted using Agisoft Lens), tick fix calibration and run alignment step (in reference mode).
I would expect everything matching with topography known, but when I upload GCP coordinates, there`s a big offset sometimes...

So basically, what would be the correct procedure to be followed when I have all these data available?
I noticed that everything improves if I optimize camera parameters based on GCP coordinates...
Could be due to different conditions between calibration "environment" and field work?
(when I took pictures for calibration aim I was a couple of meters far from sheets, now I have to build a model of rockwalls far about 400/500 meters from camera stations...).

Should I let Photoscan calculate new parameters?

And if I didn`t have GCP on the other side, is there any way to model the gorge accurately and correctly just using the calibration file and coordinates of camera stations?

Thanks for any answers!
See ya

Davide

8

General / Re: Still about GoPro and cheap UAV

« on: February 06, 2014, 07:05:20 PM »

Hi Diego ROn...
Just today I tested the GoPro Hero 3+ Black Edition on an esacopter...
I noticed that the photos are very distorted (12 Mpx - Wide), and the software is able to align them but you do not appreciate the differences in altitude...
I get much better results if I apply to the photos the Lens Correction performed in Photoshop CS6...
I complete workflow without any GCP (both aerial and terrestrial...)
I attach below some screenshots...
Bye

9

General / Re: ... about Networking Pscan

« on: February 05, 2014, 04:26:01 PM »

Hi everybody!!
I resume this old post...
A year has passed since the last response and I want to know if you have discovered a few stable solution in the meantime.
I would like to take advantage of these two computers to process my projects:

PC 1
Intel Core i5 - 2320 CPU @ 3.00 GHz (4CPUs)
NVIDIA GeForce GT 520 (4047 MB)
16 GB RAM
Windows 7 Home Premium 64bit

PC 2
Intel Core i5 - 2400 CPU @ 3.10 GHz (4CPUs)
NVIDIA GeForce GT 520 (4047 MB)
RAM 8 GB
Windows 7 Home Premium 64bit

Is it possible?
Many Thanks to everybody

10

General / Re: Aerial photogrammetry (DSM + ortho) in 1.0 for "large" projects (~1000 images)

« on: January 24, 2014, 03:03:55 PM »

Hi Andyroo!!
I have never used multiple chunks in Photoscan, since I use your same workflow but with small dataset (100-150 photos).
I haven't a workstation so it could be usefull processing these few photos in multiple chunks...
Could you explain me step by step your point 6 please?
Another question...Have you ever used a calibrated camera in Photoscan processing? How does workflow change in this case?
Thanks

11

General / Lens Calibration in Photoscan processing

« on: January 24, 2014, 01:44:05 PM »

Hi everybody.
I wanted to know if anyone has developed a workflow in PhotoScan that includes the use of a calibrated camera for aerial purposes.

I generally follow workflow proposed by andyroo here http://www.agisoft.ru/forum/index.php?topic=1804.msg10373#msg10373.

I tried to calibrate the camera using Agisoft Lens but with poor results. I then re-calibrated camera with Photomodeler and then converted the file in Lens to use it in Photoscan.

My questions are:

• Can I import the calibration file obtained for starting to process the photos as usual and then use the GCP to improve the final quality of the elaborate?
• Have I to tick FIX voice in camera calibration window?
• What parameters should I optimize then using the GCP coordinates?

Thanks to all

12

General / Re: Aerial photogrammetry (DSM + ortho) in 1.0 for "large" projects (~1000 images)

« on: January 11, 2014, 02:56:51 PM »

Thanks Andy!!
I totally agree with you on the method to be followed.
The only point in which I can't be sure yet is that about manual or automatic (gradual selection) cleaning of point cloud...
at this stage we can intervene to improve significantly the quality of the final model (according to me) and eliminate distortions caused by the lens...
can anyone suggest a workflow functional?
you can skip this step if we are in possession of a camera calibration file?
someone managed to correctly calibrate the camera and lens coupled with "Lens" to get a usable file for processing images?
Many Thanks...
David

13

General / Re: Aerial photogrammetry (DSM + ortho) in 1.0 for "large" projects (~1000 images)

« on: January 09, 2014, 09:52:03 PM »

Hi Andyroo...
I see that your workflow is quite similar to that one used for "small" dataset.
I have some question for you.

• What about gradual selection? I read that someone trim flyers and sinkers with gradual selection in so doing...select point in the sparse cloud with reproduction error higher than 1 by dragging the slider and delete them. Then they optimize the point cloud and make up to 3 iterations untill they are satisfied with accuracy. In so doing they can remove the bowl effect due to the lens before optimizing point cloud starting from GCP coordinates...
  Do you use the same workflow? Any change in 1.0.0 version of Photoscan?
• What do you mean in step 3 and 4? Could you explain it?

Thanks of all
Greatings
David

14

General / Re: Agisoft PhotoScan 1.0.0 pre-release

« on: November 04, 2013, 07:09:35 PM »

Hi Everybody...
Some new features to implement in this new version:

• Add 6 usefull view buttons (Upper view, bottom, front, back, left and right)
• Add some usefull combo for navigation mode (for example ctrl + left click to rotate pointcloud or model around z-axis, shift + left click to rotate pointcloud/3D model around x-axis...)
• Add a mesh edit mode (create polylines to bound mesh on street or clean surface, delete manually spikes or wrong vertex...)
• Add automatic identification of planes in meshed model for geotechnical purposes...

These are only suggestions.. 

Thanks agisoft team!

15

General / Re: Gradual selection???

« on: July 30, 2013, 08:16:52 PM »

Thanks Alexey for suggestions...
So my workflow changes in this way: step 1, 2, 3, 4, 5, (7+8+9), 6...

Another question about this:

In case of large point cloud model distortions (similar to bowl-effect) it could be better to optimize the alignment using only camera coordinates and only after that use GCPs

I'll never have any image coordinates available (we use camera without integrated GPS).
May I optimize point cluod only recognizing target on different images?... (image coordinates are important only in alignement process...)
Moreover, if I have no coordinates (nor images position or GCP known) because I don't want to georeferred my model, may I optimize point cloud only placing target in correct positions and then scale model?

Many thanks

David