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Multispectral plane!

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#1 Hornblende

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Posted 08 October 2017 - 14:10

Hi All :)
This summer I was in France to relax and see my family. We were living in the countryside near a very small airport which exhibit an old jet plane, the perfect subject for a multispectral set!
The pictures below were taken in VIS – UV – IR830 – Full spectrum (no filters) with my Canon 6D and the EL-Nikkor 80mm f/5.6

I really like how the UV picture is a total opposite of the IR picture :)

Attached Image: IMG_9866s.jpg
Attached Image: IMG_9864s.jpg
Attached Image: IMG_9865s.jpg
Attached Image: IMG_9867s.jpg

#2 Andy Perrin

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Posted 08 October 2017 - 16:10

Awesome! It is interesting how the strong reflections off the grass illuminate the underside of the plane in IR.

#3 UlfW

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Posted 08 October 2017 - 17:27

Nice pictures of an interestingly shaped airplane.

When I was young more than 40 years ago I was interested in different types of airplanes.

I was amazed that I still could identify this one as the trainer aircraft Fouga Magister
https://en.wikipedia...CM.170_Magister

Strange how memory works. Have not had any reason or use to remember this at all!
Ulf Wilhelmson
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#4 Cadmium

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Posted 09 October 2017 - 06:26

Nice :-)
I am of course tempted to recombine some of these into multispectral composites.
Like for example UV = Blue, Visual = Green, IR = Red.
Etc....

#5 Hornblende

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Posted 09 October 2017 - 14:53

Thanks all.
UlfW thanks for the name of the plane!

Here are some multispectral composites (names follow the R-G-B order):

G-B-UV
Attached Image: G-B-UV.jpg


R-G-UV
Attached Image: R-G-UV.jpg


IR-G-B
Attached Image: IR-G-B.jpg


IR-R-G
Attached Image: IR-R-G.jpg


IR-IR-UV (very similar to the "super-blue filter"
Attached Image: IR-IR-UV.jpg


VIS-VIS-IR
Attached Image: VIS-VIS-IR.jpg


UV-IR-UV
Attached Image: UV-IR-UV.jpg

#6 Cadmium

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Posted 09 October 2017 - 19:19

Very nice!
Did you try a G > B, R > G, IR > R ?

#7 Hornblende

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Posted 09 October 2017 - 20:07

Yes, it is the 4th image.

#8 Andy Perrin

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Posted 09 October 2017 - 20:55

IR-R-G seems like the most informative image, in the sense of being able to get an idea of what component is contributing to what. You can see the IR reflection off the bottom especially.

IR-IR-UV is the prettiest in my opinion. ;)

#9 OlDoinyo

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Posted 09 October 2017 - 22:42

You could also assemble a Wideband image (I[RGB]U-->RGB.)

#10 Hornblende

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Posted 10 October 2017 - 00:01

I did, it looks almost the same as the IR-R-G image.

#11 Andy Perrin

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Posted 10 October 2017 - 05:21

View PostOlDoinyo, on 09 October 2017 - 22:42, said:

You could also assemble a Wideband image (I[RGB]U-->RGB.)
What's a Wideband image? I'm having trouble figuring out how you get 5 channels into 3, unless your brackets mean converting the RGB part to greyscale and using it as the green of the output?

#12 OlDoinyo

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Posted 10 October 2017 - 09:27

That is what I meant--collapse the visible into greyscale.

#13 Andrea B.

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Posted 11 October 2017 - 16:14

If the greyscale of the RGB image is placed into the Green channel, isn't that the same as putting the Green channel of the RGB image into the Green channel?
Andrea G. Blum
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#14 Andy Perrin

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Posted 11 October 2017 - 17:17

No? The greyscale of the RGB is a weighted average of the R, G, and B. The green channel is just the green channel. It's not like the R and the B cancel each other somehow. Just try comparing a greyscale of an RGB to the G of the same image!

#15 Andrea B.

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Posted 12 October 2017 - 01:47

I'll take your word for it because I don't have a subscription to Photoshop!! :D
And I'm not sure I can properly extract a greyscale or a green channel in PS Elements (which I do have).

In Photoshop Elements I can get an approximation(??) of the green channel by layering green (0,255,0) over the photo and setting the blend to Multiply. But I'm not sure if that produces the actual green channel.
Andrea G. Blum
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#16 Cadmium

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Posted 12 October 2017 - 06:13

The green channel is only the green channel, whereas desaturated RGB includes all three channels.
As far as I know, 'collapsed' simply means desaturated in this case?

Hornblende, hope you don't mind this demo using your photo.
Here is the difference:
Attached Image: Plane_Visual_Desaturated_Green.jpg

#17 Hornblende

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Posted 12 October 2017 - 23:56

No problem Cadmium :)

You can see the green color of the grass is reflected under the wing!

#18 Andrea B.

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Posted 15 October 2017 - 15:43

Thanks Andy and Steve for clarifying this for me!! If I had simply thought about the definition of greyscale and green channel, it would have been obvious. But I didn't go there. :D :rolleyes:

I really should have the big CS version of Photoshop for its channel tool because making channel extracts in the little Photoshop Elements is very tedious. Recently I figured out -- finally -- how to make a channel extract in the old Capture NX2. It is a little easier there. After creating an R, G, or B channel and making a greyscale in NX2, I then have to take them to PSE for stacking in an RGB difference layer.

I also realized that one problem with my convoluted stack methodolgy is that I never see the channel shots in B&W. My channel layers are always in R, G or B -- making it more difficult to detect differences.

OK, sorry, that was all a little boring!!!! I think I was clarifying it to myself for future reference.

****************************

This plane shot is very cool. Quite interesting how the strong IR reflectivity in grasses and other green plants plays out in the various stacked versions.
Andrea G. Blum
Often found hanging out with flowers & bees.