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Field patterns visualized with ICA

Infrared Multispectral Processing
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#1 Andy Perrin

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Posted 22 September 2018 - 22:24

During last June's open-door helicopter flight (written up here), I had the opportunity to fly over a field that I'd walked across the previous week. From the air, I took aerochrome-style red/green/infrared shots using Tiffen #12 filter and the NEX-7 camera, as documented at the link. Quoting the relevant parts from that writeup, the processing steps were:

Quote

Lens: Novoflex Noflexar 35mm
F/8 mostly (as far as I can recall...) and ISO100. I didn't keep close track of the exposures, as I was busy taking photos out of a doorless helicopter at the time.

Processing:
Raw to TIFF with no white balance [in PhotoNinja]. Then, in MATLAB,
Rnew = B
Gnew = R - B
Bnew = G - B
then a white balance off asphalt or whatever was handy that looked like it ought to be white in PhotoNinja. Various adjustments to exposure and saturation, then denoising with Neat Image.

Following that, I used Independent Component Analysis (written up here using faded ads on brick walls as an example) to bring out the hidden patterns in the fields. I visualize the three ICA components by putting them in the channels of an Lab colorspace image and adjusting contrast to align the peaks of the histograms of the a and b channels.

The history of the fields is itself fascinating; they were once the Great Cedar Swamp until Cumberland Farms filled in the land in the 1970s. You can read the whole sad story at this link, but I will excerpt some pieces so you can interpret the photos below appropriately.

Quote

Beginning in 1942, National Fireworks, Inc., a Hanover based manufacturer of munitions, guided by former Peirce Trustee Chester E. Weston, starting acquiring some 200 parcels comprising nearly 1,900 acres of the swamp in Middleborough and Halifax to establish a proving ground where their munitions could be tested. Roads were driven through the wilds of the swamp, trees felled, brush cleared, and a nearly three-mile-long swath laid down and graveled from Fuller Street northwards. From the gun stand near the former Urann cranberry bogs, shells were lobbed over and into the swamp.
Yet, at times, the swamp seemingly resisted efforts to be tamed by industry. On August 7 and 8, 1943, “a fire, set by test firing,”¦.worked into the peat, and set off various unexploded shells.” As a result, two employees were injured by shrapnel.

In 1957, the ominously-named American Potash & Chemical Corporation acquired the 1,900-acre Great Cedar Swamp proving grounds with plans of its own (which fortunately went unimplemented) to carry on ordnance and explosives research, development and testing. Still later, the proposed construction of a major international airport to either supplement or replace Logan in Boston on the AP & CC property also mercifully foundered, partially due to the opposition of East Middleborough and Halifax residents who began to take umbrage at the increasingly industrial uses of their rural neighborhood as epitomized by the short-lived Kelsey-Ferguson brick manufactory which sits now rusting on River Street.

While the 1973 acquisition of the Great Cedar Swamp by Cumberland Farms might have provided a glimmer of hope for those who thought that that company might be more sensitive to the local environment, they were soon disappointed. Immediately, the regional dairy operator began to clear and fill the Great Cedar Swamp, ostensibly for the agricultural purposes of corn cultivation and cattle grazing. Yet, by July, 1973, Cumberland Farms had run afoul of local residents, as well as state and federal wetlands protection acts, by altering the swamp’s wetlands as well as allegedly using the swamp as a “dumping ground for the manure of 2,500 cows.” What seemed an interminably long period of litigation followed with the result that, two decades later, federal courts found that Cumberland had indeed violated the law by re-engineering wetlands within the swamp, and subsequently ordered the company to return a portion of the swamp back to wetland. By that time, however, much of the damage to the swamp had been done.
---

#1a:
Attached Image: _DSC8577 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#1b:
Attached Image: _DSC8577 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG

#2a:
Attached Image: _DSC8581 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#2b:
Attached Image: _DSC8581 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG

#3a:
Attached Image: _DSC8588 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#3b:
Attached Image: _DSC8588 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG


In the following two photos, the original flow of the river through the swamp shows up dramatically.
#4a:
Attached Image: _DSC8589 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#4b:
Attached Image: _DSC8589 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG

#5a:
Attached Image: _DSC8586 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#5b:
Attached Image: _DSC8586 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG

In this pic and the ICA below it, there is a rectangular patch that must have been cleared at some point by one of the companies involved.
#6a:
Attached Image: _DSC8590 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#6b:
Attached Image: _DSC8590 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.jpg

#7a:
Attached Image: _DSC8591 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG
#7b:
Attached Image: _DSC8591 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG
---------


Finally, I'll end with some visible light photos of what it looks like on the ground. I walked along the white mud path (which was littered with living snails!) that runs through the center of the former swamp. It was beautiful and filled with birds and wildflowers. The Audubon Society is trying to raise money to buy the land and save it from developers.

This is the path shown in photos 4(a, b ) and 6(a, b ):
Attached Image: _DSC8411 ambient HoyaUVIRcut Sony E 55-210mm 129mm  f10 0.0025 iso100 denoise small sharp.jpg

Attached Image: _DSC8421 ambient HoyaUVIRcut Sony E 55-210mm 145mm  f9 0.002 iso100 denoise small.jpg

Attached Image: _DSC8423 ambient HoyaUVIRcut Sony E 55-210mm 202mm  f9 0.0016 iso100 denoise small sharp.jpg

Attached Image: _DSC8415 ambient HoyaUVIRcut Sony E 55-210mm 139mm  f9 0.0001iso100 small sharp.jpg

Edited by Andy Perrin, 23 September 2018 - 01:07.


#2 WiSi-Testpilot

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Posted 23 September 2018 - 11:27

Andy, thank you for the detailed information. It is sad that the beautiful region was damaged. Your images are fantastic. I almost don’t dare to show my own field image anymore.
My other two images (original and enhanced) show the opposition effect taken with a Sony RX0 (1/400s, F/4, ISO125). The field is freshly processed and dry. The sun is behind the copter, his shadow is visible in the middle of the spot.
https://en.wikipedia...pposition_surge
Best regards,
Wilhelm

Attached Images

  • Attached Image: Maisfeld2016.jpg
  • Attached Image: Oppositionseffekt1_18_5_2018.JPG
  • Attached Image: enhanced_Oppositionseffekt1_18_5_2018.jpg

Edited by WiSi-Testpilot, 23 September 2018 - 11:49.


#3 dabateman

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Posted 23 September 2018 - 12:44

Andy,
Your 4a/4b images are amazing. I really love what you've done there. And with only a single image, not many as with the signs.
Too bad about the site, don't they know when you buy swamp land your suppose to build Disney World. Then the public will not complain.

#4 Andy Perrin

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Posted 23 September 2018 - 13:03

Thanks guys. WiSi-testpilot, I love your images also, don’t be worried about them!

Dabateman, more info (more wavelengths/channels) is always better for ICA but a lot can still be done with just three channels. I couldn’t do multiple photos of the same scene from the moving helicopter, especially since one cannot change filters with no doors to prevent things from falling out of the helicopter. Everything must be tied down. I wish I had visible photos to complement these but I only had my iPhone for that and I chose to spend most of my time using the good camera instead.

Edited by Andy Perrin, 23 September 2018 - 13:04.


#5 Andrea B.

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Posted 23 September 2018 - 16:15

Very impressive work from Andy P and Wilhelm.

This kind of multispectral analysis is so very interesting. Wish I could try it myself!

Andy P, I still think you could create a small business for this kind of thing given your skills in ICA.
And thank you for the historical reference about the land.
If you wrote up your analysis as a technical paper, where would it be published?
Andrea G. Blum
Often found hanging out with flowers & bees.

#6 Andy Perrin

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Posted 24 September 2018 - 05:20

I still think I'm not really up to making a professional job of it. I'm not an ecologist or an archaeologist, and they've been using ICA for years now anyhow. It's a standard tool of many fields (no pun! promise!) and not that special, just fun to play with.

Some more fields (not the one above) and things from the same trip:
Attached Image: _DSC8597 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG

Attached Image: _DSC8597 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab small.jpg

and a quarry:

Attached Image: _DSC8596 sunshine Tiffen#12 Noflexar F8 iso100 aerochrome.JPG

Attached Image: _DSC8596 sunshine Tiffen#12 Noflexar F8 iso100 AMUSE-ICA Lab.JPG

#7 Cadmium

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Posted 24 September 2018 - 07:24

Andy, Those are great! :-)

#8 Andrea B.

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Posted 25 September 2018 - 16:23

Yes!
I really enjoy these usages of multispectral techniques.
Andrea G. Blum
Often found hanging out with flowers & bees.