Can a Thermal Drone See Through Trees?

Why thermal cannot see through trees

A thermal camera detects infrared radiation reaching its sensor. Solid objects and dense foliage block that radiation, so the camera reads the temperature of the leaves and branches instead of the ground below.

The same applies to roofs, walls, vehicles and any other solid object.

Why animals sometimes appear visible in woodland thermal footage

• The animal is seen through a gap in the canopy.
• It is visible between branches from a particular angle.
• It is on a path, track or ride.
• It is in a clearing or felled area.
• It is near a woodland edge with open sky above.

In each case the camera has a direct line of sight. It is never seeing through the foliage.

What areas of woodland can a drone search?

• Paths, rides and forestry tracks.
• Clearings and felled areas.
• Woodland edges and the open ground beside them.
• Young plantations and areas with sparse canopy.
• Car parks, gateways and access routes.

Dense woodland

Where the canopy is closed, an aerial search cannot see the ground at all. Being honest about that matters, because time spent flying over closed canopy is time not spent searching underneath it.

Visual cameras have similar line of sight limitations

A conventional camera is limited in exactly the same way. If the ground cannot be seen, no camera on a drone will show it, whatever wavelength it works in.

When a ground search may be better

In closed woodland, thick bramble or anywhere a pet may be sheltering under cover, people on foot calling and listening will generally achieve more than an aerial search. See searching woodland for a missing dog.