Marker reprojection error changes by checking/unchecking the marker

[Ryuseiken]

Hello.
In Metashape versions 1.5.4 and 1.5.5 in my environment (Windows 10 64bit), marker reprojection error values, displayed in the rightmost column "Error (pix)" of Reference pane, often change by just checking/unchecking the marker, even though no camera parameter is changed.

This phenomena cannot be observed in 1.5.2 and 1.5.3, and therefore I guess it is a kind of bug.

[Alexey Pasumansky]

Hello Ryuseiken,

Please see my post regarding this change in another thread:
https://www.agisoft.com/forum/index.php?topic=11329.msg50857#msg50857

In Metashape Pro (and PhotoScan Pro) versions prior to 1.5.4 estimated control point coordinates displayed in the Reference pane (and the error values as well) were calculated based on minimization of the reprojection error only, without taking into account measured control point coordinates in space. So they did not correspond to adjusted coordinates from the bundle adjustment step, and were recalculated from weighted image measurements alone.
 
Starting from Metashape Pro version 1.5.4 estimated control point coordinates correspond to the adjusted values, that is, they are calculated taking into account both reprojection error and measured object space coordinates. Similar behavior is common for other software packages and also allows for better detection of the measurement errors.

If you are interested in the difference between measured and triangulated control point coordinates, you can temporary uncheck the corresponding entry in the reference pane (thus making it a check point). Please note that check point error calculation is not affected by the change mentioned above. Upon unchecking the control points you do not have to click on Update button.

[Ryuseiken]

Hello Alexey,

Thanks for your reply

I think your quoted message discuss the errors for world (LSE) coordinates of markers.
I understand that estimates of marker world coordinates from triangulation are different from those from Bundle Adjustment.
Then, how may I apply the discussion to the problem I have asked here?

I infer that the displayed reprojection error of a unchecked marker is calculated by projecting the triangulated world coordinates, while that of a checked marker is calulated by projecting the world coordinates adjusted via BA.
Is my guess correct?

In addition, let me confirm a few points regarding your quoted explanation.
I have asked here:
https://www.agisoft.com/forum/index.php?topic=11329.msg52294#msg52294

Thank you.