Using known camera positions

WIP (experimental feature)

In most of the cases this is only useful for research.

modifying existing cameras.sfm file

1. Compute the default pipeline with a set of images to the SFM node.
2. Open the SFM node folder
3. Inspect the cameras.sfm file (you can compare it to the cameraInit.sfm to see what lines need to be added with your known camera positions.) Create a new cameras.sfm file with your known camera data in a new folder somewhere.

When creating your own sfm file, remove

`"featuresFolders":... and "matchesFolders":

also set "locked": "0" to "locked": "1"

Create a new cameras.sfm file with your known camera data in a new folder somewhere. Rotation format

• in the new cameras.sfm completely remove "featuresFolders": [""], "matchesFolders": [""], (leaving this in the sfm file messes up the paths). Make sure your new sfm file uses the correct syntax and you did not miss any quotation marks (...).
• disconnect CameraInit and FeatureExtraction
• Input newcameras.sfm in FeatureExtraction
• make sure the node shows advanced settings (click on ... in the upper right border of the node settings)
• in FeatureMatching you can now select "Match from known camera poses" (only in MR2020.x)
• in StructureFromMotion "Lock Scene previously reconstructed" and "Force Lock of all Intrinsic Camera Parameters"

(to set matchFromKnownCameraPoses attribute to True in the FeatureMatching node, not available yet in the official release. Here is an unofficial, experimental build for you. It does not include latest qtAlicevision or QtOIIO, so no preview of features or models!)

References: latest #829

#399, #740, #453, #475, #300, #787, #788, #747, #807, #, #721, #725,

(Note: pose and rotation values may change from the 16+ digits after the decimal point)