Flight planning

Thermal resolution calculator.

Pick the smallest defect you need to see and how many thermal pixels should land across it. The calculator gives the furthest the camera can be from the surface, and the pixel size at the distance you plan to fly.

Thermal camera resolution Horizontal field of view (°) From your payload's spec sheet. Use the horizontal figure, not the diagonal.

Each pixel sees 0.987 mm of surface per metre of distance.

What do you need to do with the defect?

Measure its temperature3 pixels across The centre pixel sits fully on the defect, so its reading isn't diluted by the surface around it. See its shape and edges5 pixels across Enough pixels to tell a crack from a patch. Customyour own spec

Facade pass

Smallest defect (mm) Planned standoff from wall (m)

Max standoff– m

Thermal pixel size at your standoff– cm/px

Result–

Roof pass

Smallest defect (mm) Planned height above roof (m)

Max height above roof– m

Thermal pixel size at your height– cm/px

Result–

How the distances are worked out

Each thermal pixel sees about 1 mm of surface for every metre of distance (0.99 mm per metre for the camera set above). At 10 m, one pixel covers about 1 cm. To get enough pixels across a defect, the camera has to be close enough that the defect is several pixels wide.

Diagram: a camera at point A is 10 m up and 10 m across from a defect at point B. The straight-line distance between them is 14.1 m, not 10 m.

Max distance = defect size ÷ (pixels across × 0.99 mm per metre)

–

Each defect under each scenario, as straight-line distance from the camera:

You need to	Pixels across	Facade: max distance to a 50 mm defect	Roof: max distance to a 70 mm defect
Measure its temperature	3	–	–
See its shape	5	–	–

Once the camera is far enough that the defect is smaller than one pixel, its heat gets averaged in with the surface around it and it won't reliably show up at all. That's why there's no 1-pixel option.

Based on the camera set above (640 × 512, 35.05° horizontal field of view), where each pixel sees 0.987 mm per metre, looking straight at the surface. Oblique angles, wind and image blur make the usable distance shorter. A planning guide only.

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