[question] CCTAGs as reference points for road inspection

[natowi]

Question by @MarcoRos75 moved to this new issue.

Describe the problem

(original)

Salve! sto provando anche io a gestire i CCtag con Meshroom! io volevo utilizzare i cctag in un rilievo fotogrammetrico di una strada ( lunga 50m) per cui i cctag son distribuiti, non sono visibili tutti in una unica foto...ma in sequenza! questo può essere un problema o va bene comunque per il loro riconoscimento automatico?! Vorrei poi avere delle indicazioni più chiare su come fornire le coordinate nel nodo SFMTrasform... io di solito lavoro in metri....che sistema di misura usa il nodo?!?!

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(translation)

Hello! I'm trying to deal with CCTAGS in Meshroom! I wanted to use the cctag for the photogrammetric reconstruction of the relief of a road (50m long), so the cctag are distributed. They are not visible all in one photo...but in sequence! Is this a problem or is it ok for their automatic recognition?! I would like to have clearer indications on how to provide the coordinates in the SFMTrasform node... I usually work in meters....which measuring system uses the node?!?

[natowi]

The process is described here: https://github.com/alicevision/meshroom/wiki/CCTAG-scaling

A marker should be visible in multiple images. You don´t have to place markers all over the scene, but it is good to have some backup markers.
How you distribute markers depends on your capturing method. (Ground survey, by car, by drone)
The markers should be placed where they are captured in multiple images.

Place the markers in a known distance. One Meshroom unit is 100mm, so if you place the markers in a distance of 1000mm set the Additional Scale to 10

Generated CCTAG3 markers with cross and id can be downloaded here if you are not familiar with python cctag3-id-cross.zip (png&svg)

Test your workflow before using it in production.

[stale]

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