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Church LWIR pano

LWIR Infrared
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#1 Andy Perrin

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Posted 31 January 2018 - 07:57

The church down the road from me looks wonderfully dramatic in LWIR. The outside temp 17°F/-8.3°C, and the photo was taken at 1am after cooling the camera for half an hour (in LWIR, the camera makes its own light, which means cooling it gives somewhat better images).

FLIR E60, 45 pics of 25 degrees each, processed in exiftool (to retrieve the RAW), MATLAB (to adjust contrast uniformly across all the images, and also to colorize), Photoshop (for stitching), and SmartDeblur (sharpening/unblurring).

Attached Image: church3_res-UVP.jpg

And in iron colormap:
Attached Image: church3_res-iron.png

#2 Andrea B.

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Posted 31 January 2018 - 08:12

That B&W version is really beautiful!
And I just love it that you are using MATLAB to adjust contrast across your fotos. So cool!

So trees are "warm"? Relatively, anyway.
And the one car there with the bright front - it had perhaps just been driven and parked and had not yet cooled down?

You are a truly dedicated LWIR photographer to be out in 17F for this foto !!
Andrea G. Blum
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#3 Andy Perrin

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Posted 31 January 2018 - 08:31

Yes, despite their static appearance, trees are most definitely doing their metabolic things, and producing waste heat.

Regarding the car -- it takes a really long time for them to cool to the point where it doesn't show on the camera. It could have been there for as long as 2-3 hours. The truck was probably there a lot longer.

Edited by Andy Perrin, 31 January 2018 - 08:35.


#4 Andrea B.

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Posted 01 February 2018 - 16:55

It is so cool, thermally-speaking, to learn more about the world via these interesting LWIR photos. Knowing from the classroom about plant photosynthesis is one thing. Seeing this warm tree really brings home that heat is dissipated as a by-product of the tree's various chemical interactions.

With your various cameras, filters & skills, I'm thinking you could work up a very nicely illustrated classroom presentation with UV/Vis/IR and LWIR. One of my teacher friends has been after me for years to bring in some UV photos about "how the bees see".

As for the warm cars taking so much time to dissipate the heat, now I know why the occasional rodent critter has sought shelter under my car hood in winter - and one-time worked its way into the car interior to leave me little presents on the seat! It has been quite difficult to block all the small entrances to the garage.
Andrea G. Blum
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#5 Andy Perrin

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Posted 01 February 2018 - 17:29

Oh, I definitely show the students various aspects of this, especially the heat transfer students. They are studying radiation, so I can show them the image and explain to them that what we will do today is figure out how to calculate the colors in the image from first principles! It also lets me show various aspects of the physics, like that LWIR gets reflected. (Something that doesn't sink in until I hook up the camera as a webcam and hold up some aluminum foil -- yes, pointing the camera at an object does NOT always give you the temperature of the object! You might just be taking the temperature of the reflection, or some combination of the object and the reflection.)

#6 Andy Perrin

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Posted 05 February 2018 - 17:19

Redo of this one using Hugin for stitching. I tried inverting the image also, (black = hot, white = cold), which gave an interesting result.

Attached Image: church---Hugin2_res-UVP.png

Attached Image: church---Hugin2_res-inverted-UVP.jpg

#7 OlDoinyo

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Posted 06 February 2018 - 02:10

The last frame looks strangely...almost natural. One must look twice to see that it is a thermal image, a kind of uncanny-valley effect. I could see applications for this in creepy cinema.

The fact that the car at bottom center has obviously been driven recently really pops out, too.

Edited by OlDoinyo, 06 February 2018 - 02:12.


#8 Andy Perrin

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Posted 06 February 2018 - 02:32

View PostOlDoinyo, on 06 February 2018 - 02:10, said:

The last frame looks strangely...almost natural. One must look twice to see that it is a thermal image, a kind of uncanny-valley effect. I could see applications for this in creepy cinema.
Yep, and the reason is that the radiation the camera detects is proportional to the emissivity, but the reflectivity = 1-emissivity. So that means when you invert the original image, you are seeing something that is much more like a reflected-light image.

And yeah, this is very uncanny valley. At first glance it looks normal, and then...something is off.

Edited by Andy Perrin, 06 February 2018 - 02:37.


#9 Andrea B.

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Posted 06 February 2018 - 19:36

yep, weird! More frozen looking that it really even is. Or covered with alien dust!

We need to contact those people living in that house way in the background and tell them their roof is really leaking heat badly! Might save some $$$ on their heating bill. :rolleyes: :lol: OR, maybe that is just a row of Christmas lights along the roofline? Just thought of that.

And another question - why is that retaining wall under the fence so hot? Must be lights lighting it up? I think that's it but cannot see for sure.

Oh, I definitely show the students various aspects of this, especially the heat transfer students.
You must be teaching?

I had to play with the image because I've been fascinated by the obvious respiration metabolism of the trees so wanted to try a green there. I made a PS gradient overlay for the B&W version with some colours that darkened and desaturated as things grew from hot to cool. For the tree I put a green at 50% saturation and 50% brightness into the middle gradient because the tree grey was around 45-55% in brightness. For the dark almost-cold areas I used a blue of about 20% sat/brightness. I used yellow and black for the ends of the gradient. So the gradient is graded from most to least luminous colours. (Now I can't remember what layer setting I used for the gradient. "Color" I think.)
Andy, with your permission I will post a small version to show you.
Andrea G. Blum
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#10 Andy Perrin

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Posted 06 February 2018 - 21:31

Quote

And another question - why is that retaining wall under the fence so hot? Must be lights lighting it up? I think that's it but cannot see for sure.
No, I don't think so, and I don't think it's really hot. Notice how all the light colored surfaces are facing the sky? There are two reasons for that. One is that they are losing heat faster than the vertical surfaces to the VERY cold (-50F or lower) night sky, so they really are a bit colder. The other reason is that the reflectivity of the surfaces is very high at low angles. (Even with ordinary light, you see glossiness at low angles. Same thing.) So you are seeing the reflection of the night sky as well, and this is the dominant reason.

Quote

Oh, I definitely show the students various aspects of this, especially the heat transfer students.
You must be teaching?
I'm an engineering tutor, yes I teach this stuff.

Quote

Andy, with your permission I will post a small version to show you.

yes please!

#11 Andrea B.

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Posted 06 February 2018 - 22:30

Thanks for the details on that. :)
I'm not trying to be funny next, but do you think that if a person got stuck outside at night it would be better to remain vertical to stay warmer? Like don't lie down? Of course most of us don't have flat bodies/sides, but you get what I mean. I just get curious about these things.

This is the yellow/green/blue/black version. Of course, it does not convey warmth like the warm orange and purple colours do. But I enjoyed playing with the idea of grading the saturations/brightnesses and so forth. Thank you!
Attached Image: treeGreen.jpg
Andrea G. Blum
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#12 Andy Perrin

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Posted 07 February 2018 - 01:12

It’s pretty. It looks so spooky.