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LWIR panos of Harvard's Memorial Hall

Infrared LWIR
7 replies to this topic

#1 Andy Perrin

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Posted 11 November 2018 - 21:01

I happened to be at Harvard last night and I had my thermal camera with me (old-style FLIR e60, with 320x240 sensor and 25 degree FOV lens). Now that the cold weather has arrived, it is LWIR season.

Here is Memorial Hall, which is not (and never was) a church, despite appearances. It is a memorial to (quoting Wiki) "the sacrifices made by Harvard men in defense of the Union during the American Civil War‍ —‌ 'a symbol of Boston's commitment to the Unionist cause and the abolitionist movement in America.'"

Attached Image: Harvard Memorial Hall thermal infrared UVP.jpg

I also like the inverted version:
Attached Image: Harvard Memorial Hall thermal infrared (inverted) UVP.jpg

These should not be read as thermograms for multiple reasons, starting with the issues involved in fusing the images (there were 41 individual photos!). In addition, sharpening has been applied, which causes some edge glow (beyond what is there naturally, I mean), and also I have filled in some of the ragged edges in the panorama with Adobe's Content Aware Fill, so the extreme edges are not even real. Long story short, this is art, not science.

I also got some photos of those lovely arches:
Attached Image: Arches UVP.jpg

Attached Image: vis arches UVP.jpg

Edited by Andy Perrin, 11 November 2018 - 21:02.


#2 OlDoinyo

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Posted 12 November 2018 - 00:11

Quite a bit of barrel distortion on the lens.

#3 Andy Perrin

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Posted 12 November 2018 - 02:29

OlDoinyo - it’s a panorama, and I set the projection to “fisheye” so I would have to agree! :P (With the footnote that the “lens” is entirely fictional.)

Edited by Andy Perrin, 12 November 2018 - 02:32.


#4 WiSi-Testpilot

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Posted 12 November 2018 - 07:18

This are great images, considering that the resolution of the camera is very low, see for example my picture, taken with a Flir Vue 336 (x 256). How did you do it? I would like to try that as well.
Best regards,
Wilhelm

Attached Images

  • Attached Image: Max_28_8_2018.jpg


#5 Andy Perrin

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Posted 12 November 2018 - 07:33

The processing flow is basically:
1) take lots of overlapping images of your subject (in the above case, 41 images were used).
2) export the RAW as TIFF files using exiftool (I have a MATLAB script for this part, so it is done automatically as a batch, but you could use any scripting language).
3) The same MATLAB script also finds the maximum and minimum gray levels of all 41 images and linearly rescales them so that the min is 0 and max is 65535. The images are resaved as TIFFs.
4) I use the open source pano software Hugin to combine the images.
4b) [optional step] I have another MATLAB script to color map the images, but this could be done in any software, including Photoshop. This was not done above, although I experimented with inverting the grays.
5) Final post processing is done in Photoshop, and typically consists of setting the gamma/exposure and sometimes some HDR toning. Also I fill in or crop the ragged edges of the panorama, and do some sharpening.

Edited by Andy Perrin, 12 November 2018 - 07:36.


#6 WiSi-Testpilot

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Posted 12 November 2018 - 14:33

Thank you, that is a very nice project for long winter evenings.
Best regards,
Wilhelm

#7 UlfW

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Posted 12 November 2018 - 16:49

It could be fun to just play around with Hugin and normal VIS images.

Here is an impossible projection of a Hugin assembly, generated from images, shot inside an EMC measurement chamber:
http://www.ultraviol...dpost__p__18926
The source composite is actually a spherical panorama made from 16 images.
Ulf Wilhelmson
Curious and trying to see the invisible.

#8 Andrea B.

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Posted 13 November 2018 - 16:00

I'm always fascinated by LWIR and SWIR work.

I've just altered the board introduction to include LWIR, SWIR. If interest and postings increase, we could easily make those separate boards.
Andrea G. Blum
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