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New SWIR camera! NoblePeak TriWave Germanium Camera


Andy Perrin

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Andy Perrin

Late at night the Monday before last I was idly surfing eBay, checking for SWIR cameras as I often do, when what to my wondering eye should appear, but a NoblePeak TriWave camera in "new/opened box" condition. It was Buy Now only, but for a price I considered reasonable for the camera. (As it happened, the seller had slightly misrepresented the contents in several ways, out of ignorance I think, but I am still glad I bought it. It is highly unlikely that another TriWave will come on the market any time soon.)

 

To give a rundown on this very strange camera:

 

It's a TEC-cooled germanium-CMOS hybrid sensor, which means it is sensitive between 300nm and 1600nm according to the company's QE graph:

post-94-0-14403200-1557967539.png

 

The company, NoblePeak, is defunct, for reasons unknown: they had been doing fairly well at raising funds apparently, and they had a technology that was winning awards, and then suddenly they vanished around 2010ish and their assets were sold off. Despite keeping an eye out, I have not seen any of their cameras on eBay until last Monday.

 

A TriWave camera has appeared in the forum once before, in the photo by Nick Spiker here:

https://www.ultravio...v-vis-nir-swir/

 

My version of the camera seems to be nothing like as nice as Spiker's. In fact it must be a fairly early prototype, since it is completely analog and outputs only NTSC video. For all that, I'm committed to work within its limitations and I will buy it a nice frame grabber card so I can get high quality (albeit low resolution) output from it.

 

Today I wired it up and got it working on my Mac using the original software in Windows XP emulation (using Parallels), with a USB-RS232 cable and a cheap NTSC-to-USB capture stick (from Elgato). I had a few heart-stopping moments where no video was coming out, but it turned out to be due to the need to cool the sensor down to a chilly -80°C. I used a 1500-1600nm filter (blocked from UV to 1500nm) from Thorlabs, and a 50mm SWIR-AR-coated lens, also from Thorlabs.

 

Here is the current setup:

post-94-0-63901600-1557969441.jpg

 

Here is a first image (left) of a Victorian card.

post-94-0-92408000-1557968984.jpg

 

I'm quite excited to play with this camera in a variety of wavelengths, including maybe trying UVB or the "true color" UV we were discussing in the other thread, since this is a monochrome camera.

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Andy Perrin

Cadmium, that comes down to the lens, not the camera, really. It's 1/2" optics with C mount. The lens that's currently on there is a 50mm lens, but with a sensor crop factor of 5.4, it's equivalent to a 270mm lens, hence the closeups. Also, that tube I have on the front is very long, so it focuses about a foot from the lens right now. Here is a photo of my eye:

post-94-0-74780900-1557990060.jpg

 

I need to find myself a better lens, among other things.

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What would it take to shoot to infinity, or even 20 feet?

How close could you focus if the lens was closer to the cam/sensor?

Can you put a helicoid in there somewhere?

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Andy Perrin

I don't think infinity focus is a problem, you just need to put the lens at the focal length for that lens. So in this case the 50mm lens would need to be 50mm from the sensor, about 2 inches, which is nearly where it is. I was actually shopping for a helicoid earlier. When I get it, I will try a shot out the window.

 

To focus closer, you have to move the lens farther away from the sensor, right? You add extension. Since moving it farther is not an issue, I guess it just depends on finding the right extension tube?

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"To focus closer, you have to move the lens farther away from the sensor, right?"

Right, I am not worried about focusing closer. It looks rather extended away from the cam now,

so just wondering what the focus would be if the lens was close to the cam.

I think it looks really interesting!

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Andy Perrin
Oh, well, I only have the one tube and no helicoid, so I don't have a way to test it directly yet. I wasn't sure what you were asking.
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Andy Perrin

"Infinity focus" image. At 640x480 and a cruddy lens, nothing much to write home about, but it works. I still don't have a helicoid of quite the right size, I guess — this was with the lens tube removed and replaced with the little helicoid. But it was too short now, so I had to partly unscrew everything to get this photo:

post-94-0-97149500-1558138146.jpg

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Andy Perrin

No, that was around 5pm or so. Late afternoon sunshine.

 

Camera has to be tethered to the computer so probably not a park unless I can rig up some kind of tablet solution.

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Can't get enough of SWIR, so keep it going.

Maybe a shopping cart with wheels... saw some guy packing one off from the grocery store tonight, along side his bike... It made me wonder if he might have a SWIR... ;)

But, I understand.

So maybe some person in a chair in your home... which doesn't require infinity, maybe 10 feet?

Kinda like that Nick Spiker link you posted.

https://www.ultravioletphotography.com/content/index.php/topic/751-person-portrait-in-uv-vis-nir-swir/

You and Nick are the only two I have ever seen post about SWIR on here before, or anywhere else that I have seen either.

It is very interesting, I want to see more.

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Ultrapurplepix

There are occasional discussions of SWIR cameras on the EEVblog site's thermal imaging section although most of the talk there is about LWIR (7-14µm). There isn't much interest in botanicals (we haven't yet found a warm-blooded plant) but you will find a lot of discussion of the world beyond 1100nm.

 

The Gallery page (all sixteen pages - at which point the topic 'broke') is worth a look; there are for instance 100Mpix-plus images made by stitching many low resolution (320x240 to 640x480) tiles, and other discussions of techniques.

 

Here are some of my plant-related 7-14µm thermal images (and I realise I'm going way off-topic here; I promise I'll behave...)

 

post-27-0-46995900-1558616518.jpg post-27-0-22202800-1558616511.jpg

 

post-27-0-70995300-1558616530.jpg

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Andy Perrin

Back to the SWIR:

 

Today my first real SWIR lens arrived, a Kowa 12.5mm/1.4 (but keep in mind that on 1/2" optics, that is equivalent focal length to a 67mm lens! The crop factor is 5.4.) Unfortunately it needs a 35.5mm filter and all I have is 25mm, so I am not able to use the lens all the way out to F/1.4 at the moment. Also I am having trouble mounting that 25mm filter, so at the moment I am simply using the putty as shown in the original setup at the top of the thread. I need an appropriate step ring.

 

Anyway, here are some 1500-1600nm selfies with the lens.

post-94-0-35937100-1558732909.jpg

 

post-94-0-74742800-1558732922.jpg

 

F/2, 1/30", ISO100-equivalent ("analog gain = 1"). Sharpened in SmartDeblur.

 

Lens transmission (manufacturer):

post-94-0-18506800-1558734051.jpg

 

Filter transmission (via Omega, although the filter appears to be from Thorlabs):

post-94-0-98207200-1558734278.jpg

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Andy Perrin

I'm lit with a screw-in "energy saving incandescent bulb" which seems to be halogen with some kind of coating inside that is doubtless cutting most of my much-needed SWIR light out. It's getting hard to find LAMPS that will accept an ordinary halogen bulb. They are a fire hazard, and as the person in Home Depot (hardware store) told me, they are phasing them out. I am tempted to rig up some kind of dimmer to see if I can shift the peak toward IR. Not sure if the reduced brightness but shifted peak will help or hurt...

 

My hair is medium brown in visible light, with some gray now.

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Andy,

Your out the window shots look good. Also I like the self portrait. Really indicates the SWIR look. So you know its at the correct range.

I got the hallogen in a A19 frame bulb with E26/E27 base. The outer glass has the glass coating so if your careful you can cut it to get an unprotected bulb. The range is 350nm plus. I got this one from Target:

post-188-0-69861800-1558764434.jpg

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