Thermal Drones: Sensor Resolution and Legal Limits

A thermal drone is worth buying when its sensor has enough native pixels for the job and its paperwork matches Canadian law. That means a 640×512 core for roof, solar or search work, a 320×256 core only for spotting warm blobs at short range, and a Transport Canada registration plus a Basic pilot certificate.

What the resolution number actually buys you

Thermal sensors are tiny next to the visible camera on the same gimbal. DJI’s Mavic 3T spec sheet lists a 640×512 uncooled VOx microbolometer with a 12 μm pixel pitch, roughly 328,000 thermal pixels beside a 48 MP visible camera.

Halve that to 320×256 and you keep a quarter of the pixels. The Parrot Anafi USA uses a FLIR Boson core of exactly that size, and its 1280×720 thermal video is an upscale of a 320×256 capture, not extra detail.

The same trick appears at the top end. The Matrice 4T advertises 1280×1024 thermal photos, but DJI’s table shows that figure only with Super Resolution on. The sensor underneath is the same 640×512 as the Mavic 3T.

Video: Teledyne FLIR

Sensitivity is the second number on the sheet. Both DJI cores are rated ≤50 mK NETD at f/1.0, the Parrot core ≤60 mK. A lower value separates surfaces that differ by a fraction of a degree, which is what shows a damp patch under a shingle.

Every one of these cameras focuses from 5 m to infinity, so there is no close-up thermal frame of a junction box, and the Mavic 3T’s 28x zoom is digital and adds no pixels.

Frame rate is a legal spec, not a smoothness spec

The Anafi USA records thermal video at 9 fps while the DJI pair run at 30 Hz because of export law, not cost. Teledyne FLIR’s OEM support page explains that 30 and 60 fps thermal cameras are export-controlled by the U.S. government, while cores under 9 fps ship without a licence.

The same page says 640-class Quark2 and Muon cores fall under ITAR and need a State Department licence before delivery outside the United States or Canada. Canada sits inside that exemption alongside the United States.

For a static roof survey 9 fps is fine. For following a moving heat signature on the controller screen, the stutter is a real drawback, the same latency problem our FPV controller roundup approaches from the other side.

Three thermal drones by spec sheet, with the drawback each one carries

Model	Native thermal resolution	Thermal frame rate	Sensitivity (NETD)	Weight (manufacturer figure)	Drawback on the sheet
DJI Mavic 3T	640×512, 12 μm pitch	30 Hz	≤50 mK	920 g with propellers	Thermal focus fixed at 5 m to infinity; 28x zoom is digital only
DJI Matrice 4T	640×512, 12 μm pitch	30 Hz	≤50 mK	1,219 g takeoff weight	1280×1024 output is Super Resolution processing, not native pixels
Parrot Anafi USA	320×256 (FLIR Boson)	9 fps	≤60 mK	500 g mass	A quarter of the pixels; 9 fps video stutters on moving targets

Teledyne FLIR’s SIRAS carries a 640×512 Boson payload, but its page publishes no frame rate, sensitivity or weight, so it stays out of the table.

Transport Canada rules every drone in that table falls under

All three weigh more than 250 g, so none is a microdrone. Transport Canada’s category page puts them in the small drone class, 250 g to 25 kg, which starts at Basic operations.

Basic means you register and mark the drone, hold a Basic certificate (minimum age 14), keep visual line of sight, and never fly closer to or over people or in controlled airspace. Those last two need an Advanced certificate (minimum age 16) and, for controlled airspace, air traffic control permission.

The fines page lists up to $5,000 for an individual flying an unregistered or unmarked drone and up to $3,000 for flying where you are not allowed. It also tells you to respect trespassing and privacy laws.

If a sub-250 g drone would do, our guide to mini drone registration weight covers the other side of that line. If you only need to watch one property overnight, a wired unit from our outdoor security camera night-range guide does it without a pilot certificate.

Which spec to spend on

Buy native 640×512 if you will ever measure temperature or inspect at height, because pixels cannot be added later. Accept 320×256 at 9 fps only when the target is large, warm and stationary. If you fly in a city, budget for the Advanced certificate before the drone.

Thermal drone questions answered

Does a thermal drone need to be registered in Canada?

Yes if it weighs 250 g or more, and every drone in the table above does. Transport Canada requires registration and marking from 250 g to 25 kg, plus a Basic pilot certificate. Drones under 250 g are exempt but still bound by the microdrone rules.

Why do some thermal drones record at 9 fps?

Because U.S. export rules treat thermal cores running at 30 or 60 fps as controlled goods. Teledyne FLIR states that cameras below 9 fps ship without a licence, so manufacturers offer a slow video version. The Parrot Anafi USA lists 9 fps for that reason.

Is 640×512 thermal resolution really better than 320×256?

It has four times the pixels, so a target covers more detector elements at the same distance and small temperature differences resolve as shapes rather than blobs. The trade-off is weight: 920 g and 1,219 g for the DJI pair against 500 g for the Parrot.