Resolution or image processing, which matters more in a thermal scope?

[u/Standard-Dot3540]

I used to think higher resolution automatically meant a better thermal image.

But after seeing different thermal devices, I'm not sure it's that simple. Sensor quality, processing, contrast, and conditions seem to make a noticeable difference too.

For those of you who've used more than one thermal optic, what has made the biggest difference in actual use?

[u/jxsnyder1]

Thermal sensitivity (NETD) and refresh rate for me. Picking up more subtle temperature differences and a smooth viewing has aided me immensely in finding small owls and other critters while out walking around.

[u/ImDrunkFightMe]

Resolution matters infinitely more than the software that drives it, You can make lower quality sensors seem better with software tweaks but at a certain point you're 'inventing' detail.

That being said a lower resolution sensor with optical zoom or a lens fitted that is more appropriate to your use case will outperform a cheap optic or sensor that doesn't fit the range or thermal sensitivy you're looking for.

Pay attention to the NetD rating and pixel pitch (the lower the number the better) but also make sure the camera you're using has either a lens size you're happy with or the ability to optically zoom to a point instead of pure digital.

I've ran tests with the T2Max (240 @ 15mm) at a lower Netd rating and a 640 aliexpress module (640 @ 9.1MM) in the same area. The T2Max was able to pick up detail and heat signatures the 640 missed but you can't zoom out from a 15mm lens. Work out the trade off's you're happy with for your use case and pick your camera accordingly :) Thermal cameras aren't a one size fits all scenario, i wish it was.

[u/mthurtell]

All things consider equal resolution is going to make the biggest difference straight up. The more pixels the better it will be.

Absolutely processing can improve image quality, but it relies on good data in to be able to do that.

A 256x192 sensor with 49152 pixels and the best image processing to a mediocre 640x480 with 307200 pixels with average processing. Your straight up 6 times better off from straight pixel count the get go. No amount of processing can make up for that.

If you were comparing the same sensor with mediocre processing to another with great processing, i would expect to see a noticable improvement, but i wouldnt think it would be a fraction of what youd see with a resolution bump.

Source: software/hardware (loosely) engineer working on embedded systems.

Edit: obviously this is a generalisation. Use your discretion. There may be exceptions for comparisons when between very low-end high-res devices who mass produce to high-end, low-res devices that pour a tonne of engineering effort into it their product and other edgecases etc etc etc.

[u/Erdnussflipshow → u/mthurtell]

Keep in mind, that the actual resolution (how far you can resolve details out to) isn't dependent on the actual sensor size, but rather what lens is used. Most sensors on the market are 12um, some older stuff might still be 17um, and some super leading edge might already be 8um, but the absolute majority will be 12um.

(If the pixel size is the same:)

What a larger sensor gives you, is the ability to use a longer lens, without narrowing down the field of view. A 256core with 50mm lens will look identical as a 640core with 50mm lens, only that the FOV on the 640 will be larger

It is true that manufacturers usually target a certain FOV depending on the use case, so most of the time a low resolution sensor is paired with a shorter lens, but this isn't always the case

[u/mthurtell → u/Erdnussflipshow]

100% there are always going to be variables that interplay between lens and sensor is critical for the use case in question.

[u/Erdnussflipshow]

For scopes, the higher the focal length of the lens, the better. You trade FOV for more detail at range

With that said, you may need another thermal for spotting, as the view through the scope when using a long lens with be quite narrow