Cannabis Farm Detection using SCION Thermal Imaging

Thermal imaging has been used for detecting cannabis farms in buildings by seeing unusually hot walls/roofs of buildings for many years very effectively. This has mostly been via helicopters, and more recently UAVs and handheld (with screen) thermals, which are all quite expensive. A much more affordable solution is a handheld monocular thermal called the FLIR SCION.

The problem:

For spotting of cannabis farms, helicopter thermals are very expensive, as is deployment of a helicopter. UAVs require a specialist operator and restrictions on where they can be flown and are also relatively expensive. Handheld thermals with screens (thermography cameras) still cost at least £2600 +VAT for one with 320×256 resolution (needs to be 320×256 or higher).


FLIR SCION monocular thermals have “lock span” feature, allowing officers to compare buildings and detect cannabis farm heat. Most monocular thermals don’t have this feature. There are then 3 advantages to using a thermal monocular over a handheld (screen) thermal camera:

1) More affordable.
They price from £1880 to £3100 (+VAT), depending on model. vs. handheld thermals at x2 to x3 the price

2) More effective than thermals with large screens
Lenses designed for longer ranges, making them more useful to police (scan buildings from 10m to 100m away, vs. within 15m using handheld screen thermals) More covert. No screen glare when using a SCION monocular and you can stand further away to avoid looking obvious. Rugged design to cope with rough use. Less training burden on officers, as they are simpler to use.

3) SCION can also be used for other police work (unlike a handheld screen thermal):

  • Search for suspects (urban or rural) 5m up to 1100m range
  • Covert surveillance (no screen lighting you up at night)
  • SFO/ARV/CTSFO armed police team surveillance and overwatch
  • Perimeter security (festivals/events, key infrastructure such as Nuclear Power Stations and transport of dangerous materials)
  • Rural police operations (field/woods distances and farmyard searches, whilst staying covert)
  • Transport police for rail line searches (suicide prevention and recovery, metal theft, trespassing)
  • SAR to help locate people at distance at night.
  • UAV officers to supplement their UAV cameras with ground based thermal


FLIR SCION come in different lens and resolutions, depending on distance you need to see and sharpness of image. For detection of cannabis farms in buildings, the range is typically less than 100m. OTM266, PTM166 will achieve results with their 14-18mm lenses and 640×512 resolution. They will also detect a person out to 720 or 400m (look like a “blob” of heat at that range), or recognise it is a person (not a deer/cow) at roughly 216m or less.

OTM366 / PTM366<1000m<350m

Other useful features

  • Image and video save for evidence collection.
  • Wifi streaming to phone/tablet. Potential to share via 4G/5G hotspot to VMS/HQ for live sharing.
  • IP67 waterproof and 2m drop tested (rugged) with 3yr warranty (10yr on the sensor).
  • Built-in compass. GPS for all models.
  • Rechargeable battery option for 8-10hr operation life. Extend with most powerbanks in the field if needed.
  • Manual focus for OTM366, PTM366 and PTM466 models = sharper image focus.

50m range:

500m range: