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NickSpiker — Spectral comparison
Published: 2014-04-03 09:46:58 +0000 UTC; Views: 2211; Favourites: 19; Downloads: 13
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Ultraviolet, visible, infrared, swirRelated content
Comments: 36
Doesn't swir images show hoter areas as lighter and colder as darker, seems inverse here?
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You're thinking MWIR and LWIR
en.wikipedia.org/wiki/Thermal_…
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There are tons of infrared bands, much more than what we can see with visible light
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Very cool sir. I think it's interesting that your glasses block UV. I suppose that's a good thing.
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Thanks!
Haven't heard from you in a bit
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yeah, I haven't been on Deviant Art in a while. I had over 2000 deviantWatch things to look at :/. I wonder why I go through phases of interest and disinterest. I'm really into reddit right now.
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and to think white racist bigot people are truly convinced to be "white"...
Short wave infrared makes racist people look like hilarious imbeciles 
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Tis true, and I'm starting on a project to take portraits of asians, blacks, etc. and see how they look in different spectrum. I have a good idea of what their skin will look like, but not so much hair, and artificial hair dyes, etc.
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Great idea of a series, and I'm sure if will be even better than what Carla Philips did (not sure about her name) with her UV portrait series.
A SWIR nude series in the forest (swir on skin+swir on foliage and landscape) would totally do it for me Nick.
If I wasn't french and on the other side of the ocean I could pose for you for that SWIR nude in the forest series that just came to my mind haha
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Nude series would be cool, and I always wondered why all her portraits the eyes are closed
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About Carla, maybe she wanted to protect her models from having their eyes burnt by the UV lightening she used? Faces look so harsh it makes me wonder about the exact range of UV she used -OR maybe she simply wanted to show and emphase the human frail some even more by asking her models to close their eyes? IDK
ps: SWIR nudes, I would love to see or make that for sure!
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Good point, that definitely could be the case. I have the equipment and knowledge to do portraits in the 300nm range, but have neglected to do so because of the safety risk, I will probably do some research into the permissible exposure limits of shortwave UV.
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Reminds me of the trend back in 1930 or something with X-ray photography- everyone wanted to be portraited this way and of course both models and photographers would massively get irradiation.
But back to UV -I used to know the nm range for each 3 families (A,B and C) and I remember that the UVC are the less dangerous of the 3. I do need to get back to studying the ultraviolet properties and family too so I get to remember each nm range by heart
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You have present waiting on your profile page, something I called "Full-Spectrum Burning Fire", my very own way to pay tribute to the photographer who made me enter this photographic realdom of infinite possibilities...
cheers
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The short wave image is the one of most interest to me, Nick. First, the system works and works well. Looks to me that this is a better image than some of the test ones shown on the web site. Second, the dark skin and "white" hair and eyebrows show that this short wave radiation is interacting differently from NIR. The dark skin suggests almost total absorption, the "white" hair suggests good reflection. The strong absorption is probably from water in the skin, and the reflection of "white" probably because of lack of water molecules in the hair.
Very Good indeed.
David
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The system works well because it is a simple design and it outputs 12 bit RAW data, which is great!
The SWIR image is a 40 piece stitch, seeing that the sensor is only 640x480
I think you are right on the money regarding the lack of water in the hair.
I targeted the 1500nm band because it has the most absorption in the band visible with this camera
upload.wikimedia.org/wikipedia…
if you look at the chart, you get absorption over about 0.8mm, verses what you'd see with silicon (7mm) at the peak of 980nm
My next experiment will be white puffy clouds, snow and foliage.
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Thanks, Nick. So, can we make a prediction that anything with a high surface water content is likely to turn out "black" from high absorption and other materials less so?
I also notice that the "distressed" look of the chair - all the cracks in the leather, have almost completely vanished in the SWIR shot. I wonder if that has any implications?
Cheers
David
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Pretty much similar characteristics of the IR we are used to, except water is the big change, and some things are a bit more extreme, like some plastics and other materials that were black in 700-900nm are white in SWIR. I also exaggerated the SWIR water response by picking a band that is absorbed greatly by water (1450-1500nm)
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I look forward to seeing some more!
David
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Cool study! Very interesting and gnostical! Now I am thinking of another one upgrade of the IR camera
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This is fabulous Nick & a beaut presentation.
As for the very old man in the last shot, where did you get him
No but serious, where did you get the 1450-1550nm filter please?
Cheers
Col
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www.edmundoptics.com/optics/op…
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Water is a IR blocker. So a wet shirt will be black.
Col
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Sort of, it depends on what wavelength and depth of water we are talking about. Water blocks all wavelengths over some distance, but in the 1450nm band, it is almost completely blocked in under a centimeter.
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How did you record short wave infrared? AFAIK CMOS sensors' spectral range end at about 1200nm.
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any silicon image sensor, be it CMOS, CCD, etc, ends at about 1100nm, the imager I used was a Germanium based sensor
www.infraredlaboratories.com/T…
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Am I reading this correctly: the resulting image is 640x480 pixels (0,3 megapixels)? That doesn't print too well...
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Yes, but it prints well, because it is a true 640x480, no bayered data, and I stitch them anyway. The above is a 40 piece stitch, download the original .jpeg and look at it.
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Forgot about stitching, true.
Btw, have you tried to invert the 1500nm image? Looks almost like a visible b+w - but regarding the skin and hair only. Amazing!
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it's not as exciting as you would think, but yes.
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