Cold, overcast, windy conditions completely suck using thermal! The first time this happened to me I was in south texas, and I thought my 307 was messed up. Looked threw a weapon sight and I experienced the same thing. Image quality was great right after dark from a little sunshine , however the cold wind after 4 or 5 hours equalized temps of everything. You literally couldn't tell if you were looking down a sandero or looking into the brush. No issues with nvd's.
This is where fusion / dual-band imaging is king.
If the sun doesn't come out for an entire day or more, this further compounds the cool and wet (or humid) and windy conditions which degrade the thermal imaging. Also, tropical environments where everything is heated to high temperatures and rained on up to several times a day are equally challenging to thermal sensors.
The FLIR thermal scopes often seem to wash out more than the Insight thermal scopes, in the above conditions, whereby a human for example in heavy fog will show up clearly as a warm body but everything around it will appear as a white-out. The FLIR thermal cores are actually picking up much more thermal detail than your eye can distinguish, but the image management is designed to focus on highlighting the warm body vs. cooler background contrast -- as a result, the thermal signatures of the background detail are midpoint equalized. This effectively highlights the warm body against a "blank" canvass to maximize detection. However, this comes at a cost of losing the identification of things in the background that give the contextual clues needed for activities such as navigation.
When this approach is applied to fusion imaging, where the "blank canvass" is completely eliminated from the thermal view, and only the highlighted warm body is super-imposed onto the night vision image; you get the best of both sensor technologies. Many novice users of the COTI and ENVG will complain, initially, that they can't get thermal highlights of trees and other contextual, environment details. That is because the image management on these devices is coded to cut out the thermal noise. Otherwise, the firmware can be adjusted to thresholds where the very useful "outline mode" will put a thermal outline around every single object in the field of view. For demo purposes, there is a definite wow factor to this. However, it isn't useful to have everything in the field of view and their details outlined, whereby (for example) the outline of a set of warm footprints on a sidewalk becomes completely lost in the noisy outlines of all the cracks and embedded stones in the concrete.
FLIR is much more invested in dual and multi-band imaging than Insight / L3 / Eotech, which is much more mono-band focused. Therefore, in their LWIR scopes, Insight codes their image management with algorithms that do more to present and equally highlight the thermal signatures of background and contextual details. While this gives a much more pleasing and versatile experience to many customers seeking to try to leverage their one thermal only scope for both detection and identification, it actually impedes detection and interferes with identification in the dual band / fusion application. The ADUNS has pretty much the same thermal image management algorithm that is in the T-60, T-70, T-75, and when it is fused with the night vision / light intensified imaging, the results are outright eye-popping. This is headed someplace for future product capability that I really can't go into the details about.
Thus, all this to say that there is more than what meets the eye in regard to what FLIR and Insight are investing in with their different approaches. Both actually are not interested in duplicating what the other is doing well. They have some overlaps in the market space, but generally they actually do have different niches of capability they are pursuing.
IR-V