Precision Flight Data

Capture guide

Building envelope capture.

You fly; we process. This is the building envelope version of our capture specification: what the flight must cover, when to fly, what to send, and what we check when it arrives.

Nothing here needs more than a DJI radiometric thermal camera and a normal mission planner. What comes back is a 3D record of the building with a temperature at every point and the evidence behind it: how many stills saw that spot, from how far, at what angle, and more.

Step 1

What the flight has to cover.

  1. 01Three looks at every surface.Every exterior surface you care about capturing is seen in at least 3 stills from different positions, each one at or below 45 degrees of surface incidence. One look gives a reading; three give a reading we can check. Past 60 degrees, sensor readings become less reliable and eventually not usable.
  2. 02Overlap on the thermal camera.80 percent forward, 70 percent side. Thermal frames need more overlap than RGB to align.
  3. 03Pace.A still every 2 seconds, ideally every 1 second. Drone speed: 4 m/s or slower, preferably 2 m/s.
  4. 04Standoff.40 m or closer gives a 4 to 5 cm pixel on the wall, enough for envelope and roof work. 10 to 20 m gives 1 to 3 cm for joints, penetrations and smaller components. These sizes cover photos taken up to 45 degrees off straight on. Straight on, the pixels are smaller, and our thermal resolution calculator gives the exact figure.

Step 2

Pattern.

  1. 01Walls.Orbit or perimeter at two or three heights, camera near horizontal, pitched down only as far as it takes to keep the sky out of frame.
  2. 02Facade detail (optional).Head-on passes along each face at 5 to 15 m, at the same two or three heights. Adds detail on windows, joints and penetrations; the orbits alone are enough for full coverage.
  3. 03Roof.Nadir grid, then a second grid crossed at 90 degrees. On metal roofs, pitch the camera 20 to 45 degrees off nadir so the sensor takes less sky reflection.
  4. 04Start and end on a fixed reference.Begin and end each flight with a short pass over a building corner, a wall junction, or anything with a noticeable edge in the thermal image.
  5. 05Keep the sun and its reflection out of every frame.An overcast day, pre-dawn, post-sunset, or night flight makes for the best capture conditions.
  6. 06If a model of the building already exists, send it.We can plan the mission from it, and link it to the web viewer deliverable.

Step 3

When to fly.

  1. 01Before sunrise, or at least 2 hours after sunset.A daytime flight shows the sun, not the building's thermal behaviour. Cooler overcast days can work if there is enough temperature contrast.
  2. 02At least 10 °C between inside and outside.Held for three hours before the flight. Note the inside setpoint.
  3. 03Dry.No rain, fog or snow on the surface, and no rain in the previous 24 hours. Water masks everything it touches.
  4. 04Wind under 8 m/s.Cloud is fine and often better.
  5. 05Warm the camera up.Power it on early and let it settle before the first still; you know how long yours takes. A cold sensor drifts, and that drift is baked into every frame. Then trigger one flat-field calibration (shutter) and leave automatic FFC on. Use one gain mode (high) for the whole flight.
  6. 06Measurement settings.Set emissivity, reflected temperature, distance and humidity on the controller before the first still and leave them.

Step 4

Files.

  1. 01Radiometric JPEG (R-JPEG).No TIFF exports, photogrammetry software exports, or 8-bit previews. Exports strip the temperature and it cannot be put back.
  2. 02Original filenames, every file from the flight.Including the wide and zoom RGB frames, if captured.
  3. 03Untouched.No photo software, no cloud sync that recompresses, no metadata cleaner. If the EXIF and XMP are gone, the flight has no positions and is rejected at intake.
  4. 04RTK on if the aircraft has it.Without it the model still builds, but RTK always helps with placement.

Step 5

Ground truth, two minutes on site.

  1. 01One surface reading.Pick a flat, dull surface in the flight area (painted metal, concrete, asphalt; not glass, not bare metal). Read it with a contact or handheld IR thermometer within 10 minutes of the aircraft imaging it. Write down the value, the time and where it is, and take one phone photo. A handheld thermal frame of the same spot with its reading visible is better still.
  2. 02Known points, if you have them.Two or three surveyed or RTK points on hard edges (manhole, pad corner), with coordinates, the coordinate system, and a photo of each.
  3. 03Otherwise.The record is placed by the aircraft's GPS or RTK and checked against the camera's rangefinder (if equipped) and the RGB model, if provided.

Step 6

Handover.

Copy the SD card folder as it is. One zip per flight, nothing renamed, nothing sorted into albums.

<site>_<date>_<flight>/
  thermal/       Every *_T.JPG from the card
  log/           Mission file, flight log, weather
If you have it:
  visual/        Every *_W.JPG, *_Z.JPG or *_V.JPG from the flight
  groundtruth/   Ground reading(s), time, location, photos
  README.txt     See below

README.txt, one line each:

  1. 01Aircraft and camera; RTK yes or no; gain mode; minutes warmed up before the first photo; the measurement settings; inside setpoint; air temperature, humidity, wind and sky at takeoff and landing with the times.
  2. 02Your objective: to see heat loss, moisture, air leakage, or a specific defect.
  3. 03Anything unusual such as a restart or battery swap.

Zip, do not re-encode. Transfer by file link (Drive, Dropbox, SharePoint), never through a messaging app or an email client that resizes images. Tell us the coordinate system you want the deliverable in; the default is the UTM zone for the site.

Step 7

What happens when it arrives.

  1. 01Intake within one working day.We read the files you sent and tell you what the capture can and cannot give before any processing starts: Clear, Proceed with flags, or Rejected. Flags travel with the record into the report so there are no surprises at delivery.
  2. 02What comes back.The 3D thermal record in your coordinate system, the hosted web viewer, exports as DXF or E57/LAS and GeoJSON, a processing quality report that states what was received, which checks ran and what each one proves, and a point traceability report. Interpretation stays with you or your professional body; we supply the measurement and its provenance.

Try it free

Try it on a project first.

Send up to 500 radiometric thermal photos from one project, or book a flight. We check whether the capture is suitable. If it is, you receive the full 3D thermal record in your coordinate system, free.

Try it free Discuss a pilot project