GCP -> Post process cartography -> ODM + GCP -> QGIS

balthazarneveu commented 2 years ago

[ ] Check feasability of using GCP
[ ] Train @FlorinePepin on the subject.

Single image in QGIS A. It is possible but it does not work correctly in QGIS directly ! . Please check #17 ! B. Alternatives
- A tool worth mentioning https://github.com/OpenDroneMap/ODM/tree/master/contrib/orthorectify ... but it needs ODM to process many photos to reconstruct the ortho then it can orthorectify each single image ...
- ideally we'd want altitude + fov from exif to place the photo correctly on the map. somewhat similar to https://gis.stackexchange.com/questions/384756/georeference-single-drone-image-from-exif-data

I recommend always fly and move the drone around. do not stay static so you can always feed ODM with multiple frames.

Visible cartography

why? up to date compare to google earth in MapInfo / QGIS .
constraints = align accuracy ~50cm

Probably bad solutions: A: manual alignment or custom python alignment
B. test dji visible images from v1.2 in Mapinfo C. can we manually align in QGIS? -> using GCP (with GUI) in ODM , most probably yes! QGIS raster alignment?

Not the right way use GCP (ground control points) instead is what professional geometers do! see 3. :

use a high end GPS + markers to be very accurate
or use fake GCP to align into existing maps like google maps

Accuracy

It seems that using GCP (ground control points) is the right thing to do. https://www.groundcontrolpoints.com/#:~:text=Ground%20Control%20Points%2C%20or%20GCPs,visible%20in%20these%20aerial%20photos. In the following blogpost GCP+Aruco from ODM , they're using Aruco to link

super accurate locations from GPS
to the actual pixel location on the images. Link to the github Find GCP

In webODM there's a GCP graphical interface to manually select corresponding points between the drone picture & the map

Using FAKE GCP pointed on the map may be a "good enough" workaround.

Usage

WebODM

balthazarneveu commented 2 years ago

Setting fake GCP ground control points blog article ... https://turfstuf.wordpress.com/2020/09/18/fake-ground-control-points-for-drone-mapping/

AlainNeveu commented 2 years ago

Paramétrage des options pour réaliser une orthophoto avec WebODM.

On suppose que l'on dispose des images d'une mission aérienne (appelée par exemple Mission-01) Les images du dossier .../Mission-01/AerialPhotography ont été alignée avec iRDrone et placées dans _.../Mission-01/mappingMULTI/images . Dans ce dossier est aussi présent la définition de la caméra _.../Mission-01/mapping_MULTI/cameras/cameraIRdrone.json .

** Ouvrir WEBODM
          > Tableau de bord 
          >  ajouter un projet
** Dans la fenêtre Nouveau projet > donner un nom ( ex. _Mission-01_) ainsi qu'une courte description (facultatif).
                                        > +Créer un projet 
** > Sélectionner des images ( .../Mission-01/mapping_MULTI/images/ Hyperlapse-0001-1.tif ... )
** puis dans la fenêtre   
    > Nom : (par défaut un numéro de tâche est attribué automatiquement)                        
    > Noeud de traitement :  _Auto_                         

    > Option > choisir "par défaut" > Dupliquer (avec la petite flèche à droite du bouton modifier) 
        Dans la fenêtre "Modifier les options de la tâche"
        - donner un nom : IRDrone
        - modifier les options
            * camera-lens : brown
            * > importer un fichier .json >  .../Mission-01/mapping_MULTI/cameras/camera_IRdrone.json
            * fast-orthophoto :  Activate
            * force-gps :  Activate
            * orthophoto-resolution** :  1  (cm/pixel)
            * primary-band :  Green
            * smrf-scalar :  1.3
            * smrf-threshold :  0.3
            * smrf-slope :  0.05
            * smrf-window :  24
            * texturing-skip-global-seam-leveling :  Activate
            * texturing-tone-mapping** :  gamma (or none)
            * use-exif** :  Activate
            * use-fixed-camera-params :  Activate
        > enregistrer

    > Valider.

La commande complète apparaît dans la fenêtre de la tâche.

_camera-lens: brown, cameras: {"irdrone multispectral 3892 2892 brown 0.75":{"projection_type":"brown","width":3892,"height":2892,"focal_x":0.75,"focal_y":0.75,"c_x":0,"cy":0,"k1":0,"k2":0,"p1":0,"p2":0,"k3":0}}, fast-orthophoto: true, force-gps: true, orthophoto-resolution: 1, skip-band-alignment: true, smrf-window: 23, texturing-skip-global-seam-leveling: true, use-exif: true, use-fixed-camera-params: true

> Lancer le traitement

Lors du prochain projet dans la liste déroulante de la commande Option, l'option IRDrone apparaîtra en plus des options standards.

wisescootering / infrareddrone

GCP -> Post process cartography -> ODM + GCP -> QGIS #15