To Thermal Camera runners- Does your camera 'adjust' for rain?/Can you keep rain off the lens?

Laser Dirigible

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So, i've dabbled with Night Vision and have a couple of Thermal Cameras-

Ive run a FLIR Pathfindir II , (though lost it to other circumstances(it was destroyed in a unrelated incident), and just got another- Yes, I know, HUDWAY is about to come out with a $1000 one extremely soon, I might have jumped the gun on the replacement PF2 considering the cost of these FLIR units hasn't come down in about a decade and a half - oh well, lol) - But, I had one funny odd issue with it I ran into every now and then.

When I ran my first FLIR Pathfindir II- it was amazing how phenomenal it works, in a million different conditions from smoke from forest fires, doing decently in fog, hell, even spotting cops sitting down the road in speed traps- sure jammers and detectors are unbeatable as a combo- but hot car engines show up really well at night, and no one realizes how badly cars sitting on the site of the road stand out(and turning them off does no good , you'd have to sit there for over 12 hours ) - (It reminded me of my handheld thermal Cameras, which introduced me to the super power of long wave infrared vision) -

BUT, There was one funny case I ran into regarding water, that I didn't get to fully solve and would like to tackle now that I just received my second one.
The FLIR Pathfindir II sees through Downpours easily, no problem-
but eventually, unless it's really recessed in your vehicle somehow-
Water droplets from the rain tends to start to collect on the lens, over time

When this happened long enough, a bunch of big and small water droplets sticking to the front of the camera lens would cause the picture to darken.

I can simulate this perfectly with my handheld thermal camera(if i don't feel like flicking water drops onto the front of it which also works) , which lets me control the span-

By taking the lower bottom number of the two numbers of the temp span and raising it, the environment gets darker, then the warmest subjects get darker as the cooler environment washes out in darker and darker black- until it starts getting to the warmest subjects. I can take a video of this effect with my handheld since my new Pathfindir II isn't installed yet at this point in time - but this is EXACTLY what it looked like when the water droplets had built up for a while on the front of the Pathfindir II's camera

And yep, as you might have guessed- this is easy to fix with my handheld camera- take the lower number of the span, adjust it DOWN- and suddenly the environment comes into view again.
Except, the Pathfindir II doesn't let you control the span, or any settings. {Some other FLIR modules seem to let you do so, but they aren't suitable for driving or IP 69/ water proof like the PF2 or IP 67 resistant like the incoming Hudway one}

I had reached out to FLIR ages ago, but they did not give me a straight answer at the time , and did not recognize what I was talking about- though it's easy to reproduce with any thermal camera, you just have to own one or several.
I already know the PF2 has a built in heater supposedly for if it gets covered in ice- I imagine if the heater came on when the lens was covered in water, it'd possibly run off easier? Except, it doesn't get that cold in the lower parts of FL except like one week of the year , and you don't get ice.

The PF2 cannot be updated- [ I worry this might be something the HUDWAY team might need to be informed of, but they at least can push out updates]
so the next solution is covering it

- Is there any fancy way to keep water from pooling up? I suppose if you can recess the camera way back in your grill , you're set- I can't do that with my current car. Thought about RainX, hesitant to apply it to the front of the camera's germanium lens- I ALSO read online of attempts to cover thermal cameras with water resistant coatings like RainX just in general - that had no major impact.

So, i need a shroud, or a rain cover or something. The one thing I HAD managed to try before- was putting a thin plastic sheet(as thin as plastic from like a baggie),over the camera- it would cause it to go far longer before ?condensation? eventually got underneath the plastic, and built up to the degree the image started getting darker on the environment.

How do you guys deal with this?
Has anyone made any DIY ways of keeping water droplets to a minimum? I can't be the only one running tech like this
I will say this though- After having had a taste of thermal vision while driving- this is something every single driver in the country should be running. Even with the odd adjustment to water issue, the camera gives you useful vision far beyond what you would expect- and of course is insane at night.
 
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dyn0mitemat

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Would running a separate piece of glass in front of the lens work, or would it only pick up the temp of the glass then? If that would work you could do a separate piece in front of it with a headlight washer/wiper arm to clean it off.

I'm guess it won't see through the glass though so idk what else would work well.
 

Laser Dirigible

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Would running a separate piece of glass in front of the lens work, or would it only pick up the temp of the glass then? If that would work you could do a separate piece in front of it with a headlight washer/wiper arm to clean it off.

I'm guess it won't see through the glass though so idk what else would work well.
Correct, thermal cameras don't see through glass* ,otherwise we could run thermal cameras behind the windshield.

Thermal cameras CAN see through special glass transparent to long wave infrared, or midwave infrared(not common for the cheaper cameras used for stuff like this as opposed to aircraft) - but that's not automotive glass, so i don't think i can go get some germanium and cut out my windshield and put a germanium circle in it for my thermal camera.

Doing the headlight washer wiper thing- Is that something achievable on the tiny half inch front window of a FLIR Pathfindir 2?
 

bslaws

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I used to have a Flir pathfindir II. I used mine only at night. Never really dealt with extreme rain but never noticed any issues. They don't do well in heavy fog
The water droplets block the heat from objects. The lens on the Flir is heated but would get snow, fog and slush frozen on it if the temperature was below about 5 degrees Fahrenheit. Here are some videos
-- Double Post Merged: --
 
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Laser Dirigible

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I used to have a Flir pathfindir II. I used mine only at night. Never really dealt with extreme rain but never noticed any issues. They don't do well in heavy fog
The water droplets block the heat from objects. The lens on the Flir is heated but would get snow, fog and slush frozen on it if the temperature was below about 5 degrees Fahrenheit. Here are some videos
-- Double Post Merged: --
Hah, i recognize you- it was your videos and neat images of your coolio install , that led me to originally considering doing a top-of-hood mount originally when i had installed the first one i had(I lurked on here for a long time before getting this account)

I've had success in heavy fog in that- It gets a bit degraded, but it beats eyesight by a little.

I suspect it's more the droplets than rain itself, as the pathfindir II wouldn't immediately have the issue i mentioned until a bit of time had passed in rain.

It sounds though like some sort of cover or shroud woudl be useful in slush and snow(when it builds up) conditions as well possibly...
 

bslaws

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Research IR windows. They are expensive but once in a while they come up pretty cheap on Ebay. They still would freeze in the winter. I considered getting a weather right box and making an enclosure for a cheap thermal camera. The box would have to be heated in order to prevent freezing.
-- Double Post Merged: --
I never tried it but Rain-X may also help. Just not sure what it would do to the germanium lens.
 

dchemist

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What about Perspex or similar IR transparent polymer similar to what folks put in front of LJ heads?
 

dyn0mitemat

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If you find a piece of plastic or glass that would be transparent to the camera you could do something like AVE did with his gopro's to keep coolant off the lens in the CNC Mills


 

protias

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I had a 300D for a number of years and my picture was never all that clear, probably because I never had a good screen...
 

Laser Dirigible

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Research IR windows. They are expensive but once in a while they come up pretty cheap on Ebay. They still would freeze in the winter. I considered getting a weather right box and making an enclosure for a cheap thermal camera. The box would have to be heated in order to prevent freezing.
-- Double Post Merged: --
I never tried it but Rain-X may also help. Just not sure what it would do to the germanium lens.
I see there's several Germanium, and Zinc Selenide windows that might work -
I see a few here have worked with Perspex in the case of Jammers, but Perxpex does not appear to be transparent in the LWIR area of the spectrum..

One would have to find a shop that would be willing to work with one of these germanium window discs , and then see if they would build a 3-d Printed Enclosure(if there was the room for it), or at least some sort of cover, to go over the front of a Pathfinder II so that water just runs the flat piece.
I wonder how the Germanium or Zinc window could be held onto the camera in a good manner for everything from hot to cold weather.


With the limited room of installs- I don't think one would need a full set weather box unless the camera was fully outside the vehicle(such as your case with the elevated mounted thermal camera it looked like you had) , but getting it so you have a cover in front of the camera, and then maybe trying rain X or a similar hydrophobic coating on that, as one can always eventually replace the window.
-- Double Post Merged: --
What about Perspex or similar IR transparent polymer similar to what folks put in front of LJ heads?
Looking around, charts I've found like these links below make it look like Perspex only works for NIR bands like where jammers operate, and a bit onto SWIR, not MWIR , or LWIR where the majority of thermal stuff we see and the Pathfindir 2, operate

 
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