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Messages - dcobra

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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.

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


Thank you.  The tweaks are the same in both versions.  The only one that is listed was there by default (main/refine_max_gpu_multiplier).

The alignment parameters are slightly different between them:

f, cx, cy, k1-3, p1-3

f, cx, cy, k1-3, p1-3, additional corrections

I enabled p3 in 1.6.0 in the console as it was removed from the GUI.

I noticed in the logs that the GPU driver/runtime is different:

1.6.0 is 10020/8000
1.5.3 is 10020/5050

I just finished a small test where I opened a project that was optimized in 1.6.0 with parameters noted above in 1.5.3 and processed the dense point cloud.  The speed has returned to normal but the resulting dense cloud is still noisy.

Thanks Mak11.  The logs show GPU usage to be 100% during depth maps for both versions.  1.6.0 is just much slower.  Below are durations for both.  Attached is a screenshot showing the difference in noise.

depth map generation = 3:13
filtering = 1:41
Total ~5hrs

depth map generation = 1:04
filtering = 0:51
Total ~2hrs


Thanks for the response.  I emailed the logs as they to large to post.  I will look into getting you the dataset.  A few things to note between the two logs:

- The CPU is at 100% with very little if any variation for the duration of processing.
- The GPUs do not seem to be at 100% use very often.  I monitor them with ASI Afterburner.  They are much more active with 1.5.3.

- The CPU is quite active but not at 100% all of the time.  There is some variation.
- The GPUs are much more active and the fans are almost at max speed.

One thing I notice in the logs is that the "timings" are much higher with 1.6.0.

General / V 1.6.0 - Dense cloud generation time longer, increased noise
« on: January 14, 2020, 06:58:25 AM »
I have processed the same project in 1.5 and 1.6 and the dense cloud in 1.6 takes longer to generate and the result is much noisier.  Have tried the max neighbors tweak = -1 with no improvement.  Anyone else experiencing similar issues?

General / Re: Agisoft Metashape 1.6.0 pre-release
« on: November 13, 2019, 04:45:54 PM »
Could you please provide more information on the additional calibration coefficients?  What additional coefficients are used compared to the standard Brown model and how are the equations different?

Thank you

I am curious to know what Fit additional corrections option do in Optimize Cameras dialog?....

What are these corrections and when should we use this option?

Hello Paulo,

Fit additional corrections option enables additional calibration coefficients that allows a better fit of the lens distortion model. This is especially important for wide angle lens with large radial distortions, e.g. DJI Phantom 4 RTK camera.

This option is mainly intended to be used in cases when highly accurate reference data is available (RTK/PPK) and it can help to achieve higher accuracy when no GCPs are available.

General / Re: Adaptive Camera Model Fitting which step
« on: July 31, 2019, 01:28:45 AM »
I'm quite interested in the as well.  I have noticed that when I check adaptive fitting during the alignment stage I get lower error than if I don't check it.  The more surprising part is that if I optimize with adaptive fitting checked after aligning without adaptive fitting checked, the error is higher than if I simply aligned with adaptive fitting checked.  This suggests that they are indeed doing something different.

I see similar results, although to a lesser degree, with my A7R III and 18mm Batis.  This is with stabilization and all in camera lens corrections off.

General / Re: Camera Calibration and Distortion Plot
« on: March 08, 2019, 01:57:06 PM »

Thanks for the reply.  I think you are right, the vertical axis being unsigned is what is making it look so odd.  Including P3 and P4 do appear to improve the model based on a few observations: 1) lower control to check point RMSE ratio and 2) more randomly orientated and lower image residuals, although there is greater correlation between parameters when included (see image attached). 

General / Camera Calibration and Distortion Plot
« on: March 07, 2019, 11:27:17 PM »

I've been experimenting with camera calibration parameters and have processed a model with two different configurations.  The configurations are as follows:
1 - F, Cx, Cy, B1, B2, K1, K2, K3, K4, P1, P2
2 - F, Cx, Cy, B1, B2, K1, K2, K3, K4, P1, P2, P3, P4

These two configurations give quite different distortion plot results and I am trying to understand the meaning of them (see image attached).  The first distortion plot seems quite realistic, increasing distortion with increasing radius.  The second distortion plots looks odd, but gives better RMSE on check points, and there is lower distortion in the decentering plot.  Is the second plot realistic?  Or is it a case of over parameterization? Any advice you have is appreciated.

General / Re: Lines in Dense Cloud
« on: January 19, 2019, 01:49:31 AM »

Thanks for the suggestion.  There doesn't appear to be any white lines in the images or any errors with the regenerated texture.  See dense cloud and texture attached.

General / Re: Lines in Dense Cloud
« on: January 17, 2019, 06:16:54 PM »

Thanks for the reply.  See screenshots attached of sparse and dense point clouds in same area.  There doesn't appear to be any lines in the sparse point cloud. The lines in the dense point cloud do look like some kind of border though.

The images were captured with 60%/80% overlap. 

General / Re: Lines in Dense Cloud
« on: January 17, 2019, 05:26:08 AM »
As an update, I have reprocessed this data set with Photoscan 1.4.5 and am observing the same results.

General / Lines in Dense Cloud
« on: January 16, 2019, 05:05:08 AM »
I have noticed some odd lines in some recent dense point clouds.  They are quite visible when viewing the model from the backside.  The lines are raised slightly beyond the backside of the actual surface of the model.  See screenshots attached as an example.  Dense cloud was processed using Metashape 1.5.0.  Any guidance as to what is causing this and how to remedy would be appreciated.

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