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Messages - dcobra

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1
General / Laser scan improve image alignment?
« on: May 13, 2022, 10:34:10 PM »
Hello,

I have been looking into including laser scans in my models and am wondering if including them will improve image alignment.  In particular I'm interested in improving systematic error/doming effects.  If I create a photogrammetric model and include laser scans throughout the model can I expect an improvement in image alignment and reduced systematic error/doming?

Best,
Cody

2
General / Re: V1.7.0 - Increased RMS reprojection error
« on: January 07, 2021, 03:43:22 PM »
Thanks Alexey.

3
General / V1.7.0 - Increased RMS reprojection error
« on: January 05, 2021, 09:26:33 PM »
I've noticed an increase in RMS reprojection error in V1.7.0 compared to V1.6.5.  I have attached screen shots of project info from a model processed with the same parameters in both versions.  In V1.7.0 RMS reprojection error is 0.424 px and in V1.6.5 it is 0.331 px.  I also notice that there is a notable decrease in the number of tie points in V1.7.0.  I'm assuming that the difference in RMS is attributed to how the tie points are being selected and filtered.  Also interesting is the increase in tie point multiplicity and increase in max reprojection error in V1.7.0.

Is this expected behavior and why is it happening?  Does this have any effect on model accuracy?  Any advice would be greatly appreciated.

4
General / Re: Agisoft Metashape 1.7.0 pre-release
« on: January 04, 2021, 07:00:01 PM »
I'm noticing higher reprojection error in this release.  Have there been changes in image alignment to cause this?  On a model processed in 1.6.5 I'm getting ~0.3 pix RMS and in 1.7.0 I'm getting ~ 0.4 pix RMS.

5
General / Re: Export Camera Calibration with Additional Corrections
« on: November 16, 2020, 04:19:59 AM »
For anyone interested, if you only check the parameters that you are interested in fixing rather than "checking all", you can optimize with "fit additional corrections".

6
General / Export Camera Calibration with Additional Corrections
« on: November 14, 2020, 03:01:31 AM »
Is there anyway to export the camera calibration and include the additional corrections?  I would like to use a calibration from one project on another.

Or is there a way to include "fit additional corrections" when optimizing a project when the camera calibration is fixed?  Fit additional corrections is currently greyed out when trying this.

Best,
Cody

7
General / Re: Agisoft Metashape 1.7.0 pre-release
« on: October 29, 2020, 03:26:38 AM »
I can't seem to use GPU for depth map generation.  I get the following error:

Warning: Device GeForce GTX 1070 Ti ignored because it has 5958/8192 MB available, but 6870 MB required

Log up to that point is attached.  I have two identical GPUs and haven't had any issues like this in the past.
Hello dcobra,

Please check, if it helps to set up the following teak to 40 value, via Advanced Preferences tab -> Tweaks dialog:
main/depth_pm_max_neighbors

Alexey,

Thank you for the suggestion.  It worked.

Best,
Cody

I just finished processing a dense point cloud and the result is amazing.  Much less noise than previous versions.  Great work!

8
General / Re: Agisoft Metashape 1.7.0 pre-release
« on: October 28, 2020, 04:27:03 PM »
I can't seem to use GPU for depth map generation.  I get the following error:

Warning: Device GeForce GTX 1070 Ti ignored because it has 5958/8192 MB available, but 6870 MB required

Log up to that point is attached.  I have two identical GPUs and haven't had any issues like this in the past.
Hello dcobra,

Please check, if it helps to set up the following teak to 40 value, via Advanced Preferences tab -> Tweaks dialog:
main/depth_pm_max_neighbors

Alexey,

Thank you for the suggestion.  It worked.

Best,
Cody

9
General / Re: Agisoft Metashape 1.7.0 pre-release
« on: October 27, 2020, 04:30:17 PM »
I can't seem to use GPU for depth map generation.  I get the following error:

Warning: Device GeForce GTX 1070 Ti ignored because it has 5958/8192 MB available, but 6870 MB required

Log up to that point is attached.  I have two identical GPUs and haven't had any issues like this in the past. 


10
General / V 1.6 marker accuracy weighting
« on: March 11, 2020, 02:55:49 AM »
I have noticed that there has been a change in how Metashape weights marker accuracy (measurement accuracy) from V 1.5 to V 1.6.  Marker accuracy seems to have a much stronger weighting in V 1.6.  Lower values (below 0.001m) tend to force the point cloud to conform to the control points, whereas in V 1.5 there was much less of an effect.  The error observed on control points is reduced as the accuracy value is lowered.  Can Agisoft confirm the change and provide some additional info?  Have the other weightings been changed?

Attached are two screen shots of the same project optimized in V 1.5 and V 1.6 with marker accuracy set to 0.0001m.  Note the error on control points is much lower in V 1.6.

Best,
Cody

11
General / Re: V 1.6.0 - Dense cloud generation time longer, increased noise
« on: February 14, 2020, 03:13:43 PM »
Any updates on the noise issue? I am noticing it in many more models.

12
General / Re: V 1.6.0 - Dense cloud generation time longer, increased noise
« on: February 06, 2020, 07:24:29 PM »
Alexey,

I'll email you a link to download a project.

Best,
Cody

13
General / Re: V 1.6.0 - Dense cloud generation time longer, increased noise
« on: February 04, 2020, 03:03:54 AM »
I haven't gotten any updates from Agisoft on this, although I have made a few observations and have been able to reduce the noise significantly.  I'll try to summarize below.

On models that showed increased noise I noticed that the residuals looked quite systematic (fairly strong patterns) compared to those that did not have increased noise.  Parameter selection for models was done using the process described by James et al.  To reduce noise I chose the parameter set that gave the lowest RMSE without "fit additional corrections'.  Once this was determined I optimized with "fit additional corrections' enabled.  Finding a suitable parameter set first seemed quite important.  The resulting dense cloud was very close to what I was seeing in 1.5.3.  The accuracy with 'fit additional corrections' is also improved as verified by measurements extracted from the model and compared to 3rd party measurements. 

It became quite obvious if the dense cloud was going to have noise or not by the residuals.  If they were systematic the dense cloud ended up with significant noise and if they weren't the dense cloud was quite good. 

I do notice different results with different lenses.  I get better results, and better looking residuals, with my 21mm than I do with my 18mm.  Perhaps the 18mm is harder to model. 


14
General / Re: Sony A7rii for photogrammetry and lenses
« on: January 29, 2020, 04:20:53 PM »
Forgot to mention that in addition to the sensor moving freely when the camera is powered of, the lens also moves focus (to infinity I believe).  When powered off and then back on the focus moves back to the previous setting, unless the battery is removed then it resets to infinity, but again the precision is unknown.  It likely isn't the exact same position and my suspicion is that this creates an even greater error than a shift in sensor position.  I would recommend using a fully manual lens and taping the focus ring if possible.  If not consider my previous recommendation.

15
General / Re: Sony A7rii for photogrammetry and lenses
« on: January 29, 2020, 04:06:39 PM »
The Sony A7Rii does have sensor stabilization, which likely isn't good for photogrammetry as remotesense has pointed out.  The literature recommends turning all such features off.  I'm still waiting for a good paper to assess whether or not turning those features off is enough or if cameras with them should be avoided. 

I have been successfully using an A7Riii with a Zeiss Batis 18 mm lens with good results.  I have compared measurements taken from the models to third party measurements and note differences on the order of a few mm on models ~15 m in size.  I do wonder if I would see an improvement if I used a camera with a fixed sensor.

Something to consider is that the sensor does freely move around when the camera is turned off and it is only when the camera is powered on that it is rigidly held in place.  If you power the camera off during a shoot and then back on, the sensor may not be in the same position as previously.  I don't know what the precision of the sensor positioning system is.  I would suggest leaving the camera powered on during an entire shoot, and if that is not possible then possibly creating separate camera calibrations.

Hope that helps
Cody

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