Multispectral data acquisition with WingtraOne RedEdge

A guide to the special workflow for preparing and executing a WingtraOne RedEdge flight.

MicaSense RedEdge is a multispectral camera that is designed for aerial photogrammetry. It features more functionalities and slightly different requirements than WingtraOne's RGB payloads, so it requires a different workflow. The following information will guide you on how to use this combination and acquire your multispectral data successfully.

  • In the WingtraPilot welcome menu, create a new flight plan, and select "Micasense RedEdge" as the camera
  • Plan your flight as described in Create a new flight plan
  • Perform the preflight procedure as described in the chapter Preflight checklist; the steps that differ from the RX1 or QX1 workflow are described below

Configure RedEdge

On preflight check number seven, you have to configure the RedEdge camera to match the desired flight plan parameters in a separate camera user interface. This user interface can be accessed via Wifi and web browser (Chrome). You can use the tablet itself or any other device such as your smartphone.

To configure RedEdge camera:

  • Power on WingtraOne
  • Connect via Wifi to the RedEdge camera (SSID = rededge // password = micasense)
  • Open the browser app (Chrome) and access the page http://192.168.10.254
  • Go to status tab (house tab). Check the free space on the SD card, GPS signal reception, and time

wingtraone_rededge_status_tab

  • Go to the configure tab (gear tab). Set auto-capture mode to overlap. Set the target altitude to the altitude of your flight plan. Set along-track overlap to the frontal overlap of your flight plan. Press save.

wingtraone_rededge_configure_tab

  • The flight path is defined by WingtraPilot parameters (flight altitude, flight direction, and side overlap). The triggering is set by the MicaSense web user interface (based on target altitude and front overlap). For consistency, specify all parameters in both user interfaces correctly.

Calibrate RedEdge camera

On preflight check number 11, the RedEdge camera needs to be calibrated with the provided reflectance tag. Only a timely calibration guarantees reliable spectral information of your covered flight area. For optimal calibration, make sure to take a calibration image before and after each flight.

To calibrate RedEdge camera:

  • Make sure an SD card is inserted in the RedEdge camera
  • Place the reflectance tag flat onto level ground 
  • Power the camera by plugging in the WingtraOne flight batteries. Lift it up, and hold it with the camera facing the reflectance tag, at about one meter (3 ft) above the reflectance tab. Make sure to hold WingtraOne level, and do not cover the reflectance tag with a shadow from you or the the drone, as demonstrated in the following image:

wingtraone_rededge_calibration_1

  • Trigger at least one image of the reflectance tag by pressing the button on the front of the camera for less than one second. If you press for longer than three seconds, the camera will turn off, and it will not automatically turn on during the flight.
  • Another way to trigger an image is through the web interface. The image taken will be streamed to the web interface immediately such that you can make sure the picture you take covers the reflectance tag.

Fly the mission

  • Complete the preflight checklist and start the flight
  • After landing, perform the following two steps before shutting off WingtraOne:
    • Take another calibration image by holding WingtraOne over the reflectance tag and clicking the button on the front of the WingtraOne RedEdge (< 1 s)
    • Shut off the RedEdge Camera by holding the button (3 s)

RedEdge geotagging

  • After shutting off WingtraOne RedEdge (first camera, then drone), retrieve the SD card from the camera
  • The SD card contains the images, which have already automatically been geotagged. The metadata, such as geolocation, is written to the EXIF of each image
  • The images are stored in folders (“0000SET”, “0001SET”, ...). A new folder is created each time the camera is powered up or if the maximal number of images per folder is reached
  • For every trigger event, the information from each spectral band is saved in a separate image. The 5 grayscale images represent the following 5 narrow bands: Blue (475 nm center, 20 nm bandwidth), green (560 nm center, 20 nm bandwidth), red (668 nm center, 10 nm bandwidth), red edge (717 nm center, 10 nm bandwidth), and near-IR (840 nm center, 40 nm bandwidth).

More information

For more information about the WingtraOne RedEdge setup, please have a look at the Setup the MicaSense RedEdge camera article. For further information about the RedEdge camera please refer to Micasense RedEdge Manual.