Thread: Carrying thermal monocular in the bush

Can anyone enlighten me please as to whether the colour temperatures on any of the thermal imaging handhelds owned and used for hunting are manually adjustable? Or are they typically fixed and factory preset? Or do they move based on the average IR frequency & intensity being received across the sensor?

If factory preset then presumably it can be observed that the colours have indeed been "hard wired" while being optimised for distinguishing the body temperature of mammals, perhaps in a surrounding environment that goes down to 0°C? This might mean that typically objects above say 35°C would all be of the one colour (of what ever colour palette has been selected) and 0°C and below would also all be the one colour, with the image being made up of the colours between these two extremes.

If operating in an environment where the overnight temperature only dipped to 15° (setting aside radiated losses to below this for now) then it seems that a chunk of the palette would no longer be available in contributing to the image. So perhaps the imagers instead are self-calibrating based on averaging, with the palette being automatically allocated to better depict IR frequencies that are typically emitted from objects between 15°C and 35°C?

Anyone able to offer any insights please ?

pretty sure my Sytong self-adjusts, as it really noticeable when you scan from land to water as the image briefly freezes then the colour "shades" change... @55six will be able to tell you more I'm sure...

Originally Posted by Puffin

Can anyone enlighten me please as to whether the colour temperatures on any of the thermal imaging handhelds owned and used for hunting are manually adjustable? Or are they typically fixed and factory preset? Or do they move based on the average IR frequency & intensity being received across the sensor?

If factory preset then presumably it can be observed that the colours have indeed been "hard wired" while being optimised for distinguishing the body temperature of mammals, perhaps in a surrounding environment that goes down to 0°C? This might mean that typically objects above say 35°C would all be of the one colour (of what ever colour palette has been selected) and 0°C and below would also all be the one colour, with the image being made up of the colours between these two extremes.

If operating in an environment where the overnight temperature only dipped to 15° (setting aside radiated losses to below this for now) then it seems that a chunk of the palette would no longer be available in contributing to the image. So perhaps the imagers instead are self-calibrating based on averaging, with the palette being automatically allocated to better depict IR frequencies that are typically emitted from objects between 15°C and 35°C?

Anyone able to offer any insights please ?

Firstly forget about IR (infra Red) that is the domain of NV devices and not thermal. Thermal images are a measure of the temperature difference of what you are looking at, So in colder weather you will get a greater difference between the animal body temp and the surrounding ground or foliage temp. My experience is that even in warmer conditions you will still see the full colour pallete of whatever colour pallete you have chosen. The thing with Thermal images that give you temperature difference is the NETD spec of the unit which is measure in Mk or millikalvin. the lower this number, the more sensitive the unit is to temperature difference. So thats the simple layman's description. Now, in my experience there are only 3 palletes worth using, Black hot, white hot and red hot. Black hot seems to give a higher definition and is good in open country, White hot and red hot works better in denser cover where it makes it easier to pick false signal. I like the red hot because it seems to pick an animals body heat out better from false sinals like trees stumps and warm ground. That probably only answers part of your question but I hope it sheds some light (no pun intended) on how they work and what you see.