SWIR Images - InGaAs Linescan Camera

[Daniel Csati]

I finally figured out all the settings with my InGaAs linescan camera setup. Here are the first photos. Most of them full InGaAs spectrum, I still don't have my 1575nm bandpass filter - it should look even nicer with a filter. I used a VIS Nikon 50mm lens.. A proper SWIR lens wouldn't make big difference regarding the resolution, especially with the bandpass filter. The VIS lens has however only 40% average transmission in SWIR. 

 

Landscape SWIR 800-1700nm

 

VIS (400-800nm for comparison) 

 

The next is isopropanol and water (800-1700nm)

 

VIS (400-800nm)

 

Another mountain

SWIR (800-1700nm)

 

SWIR with uncoated silicon wafer filter (ca. 1100-1700nm)

 

 

VIS (400-800nm)

 

VIS full spectrum (400-1200nm) with my ASI294MM (monochrome CMOS) and 50mm lens

 

And finally ASI294MM with 860nm longpass (860-1200nm)

 

I still like this last photo the most, but I'm very excited to discover more SWIR . :)

[colinbm]

Thanks for sharing

[Fandyus]

Now that's what I like to see! For obvious reasons of gear scarcity and high price, the SWIR content on this forum has been rather lacking, but it's a very interesting part of the electromagnetic spectrum. It would be great if you did some portraits next :)

 

Fascinating images.

[Daniel Csati]

Thanks Fandyus. I managed to put the SWIR cam together from about $2200 and it's portable so I'll be sharing some more. I haven't done many portraits before but I'll try that too ;)

[Fandyus]

5 minutes ago, Daniel Csati said:

Thanks Fandyus. I managed to put the SWIR cam together from about $2200 and it's portable so I'll be sharing some more. I haven't done many portraits before but I'll try that too ;)

Great to hear.

By the way, I had the need to merge two of the photos into a color shot.

 

[Daniel Csati]

1 minute ago, Fandyus said:

Great to hear.

By the way, I had the need to merge two of the photos into a color shot.

 

WOW, Nice!! I'll save this to my collection

[Fandyus]

1 minute ago, Daniel Csati said:

WOW, Nice!! I'll save this to my collection

Glad you like my quick edit :)

[Stefano]

Very nice! I feel like there's a lot of potential with your camera. The resolution is higher than usual SWIR cameras, which is certainly good.

[Daniel Csati]

1 hour ago, Stefano said:

Very nice! I feel like there's a lot of potential with your camera. The resolution is higher than usual SWIR cameras, which is certainly good.

It's 1024pixel vertical and practically unlimited in the horizontal direction. I find 1024 acceptable. :) 

I was thinking maybe doing more recordings and then stitching them together could help to increase the image size further. I wonder how that would work.

[Andy Perrin]

This is some fantastic work. I’m really tempted to get a turntable or a pano head and try it with my camera.

[Daniel Csati]

7 minutes ago, Andy Perrin said:

This is some fantastic work. I’m really tempted to get a turntable or a pano head and try it with my camera.

Thanks Andy. Syrp Genie Mini is my recommendation for rotation: adjustable speed, angle, step or continous settings, battery, Bluetooth.

 

By the way I offer my help for everyone on the forum who wants to build this setup. It's a rough ride, but it's worth it.

[Andy Perrin]

Since I would want more than 480px vertically, I think I would go with a pano head. Then I could use a really long focal length lens and get very detailed images with lots of megapixels. 

[Stefano]

The only disadvatage being that the subject must be stationary, while with a normal camera like Andy's TriWave you can take images more "normally".

[Daniel Csati]

38 minutes ago, Stefano said:

The only disadvatage being that the subject must be stationary, while with a normal camera like Andy's TriWave you can take images more "normally".

That's definitely a disadvantage of the linescan solution. It took 7s per photo now because of rotation speed limit. However, the camera can record up to 44k lines per second. Using a resonant mirror synchronized with the camera it would be possible to do 15FPS video with proper lighting. Anyway, it's a lot more work to build that than the slow rotation 

[Andy Perrin]

How portable is your setup? With the Triwave it needs AC power from the wall or a really hefty battery pack (in principle, I haven't tried it). Also a computer, but of course laptops are a possibility there.

[Daniel Csati]

That's the same with mine. I need AC for the power supply of the camera and frame grabber. I use a Xtorm compact AC power bank for that. The total power consumption is about 10W so it takes hours to deplete it competely. The total set: laptop (runs on battery), Syrp Genie Mini (has also battery for hours), tripod, cameralink cable, ethernet cable, 2x AC to 12V PSUs, power bank. About 3.5kg altogether

[Andy Perrin]

Yeah, it looks pretty similar to mine in terms of the total. My camera is a bit larger but my frame grabber is much smaller. One difference is that my camera is cooled, so it has a pretty high power requirement by comparison I think, 60W by the "12V @ 5A" written on the camera.

[Daniel Csati]

2 minutes ago, Andy Perrin said:

Yeah, it looks pretty similar to mine in terms of the total. My camera is a bit larger but my frame grabber is much smaller. One difference is that my camera is cooled, so it has a pretty high power requirement by comparison I think, 60W by the "12V @ 5A" written on the camera.

I'll have to double check the power consumption because this is also cooled. I use the factory default 30°C, it shouldn't require too much power at that setting. Anyway, the power bank is 71Wh capacity. Even at 12Vx5A max it should last more than an hour.

[Andrea B.]

Wonderful contribution to UVP. Thanks, Daniel !!

[Andy Perrin]

26 minutes ago, Daniel Csati said:

the power bank is 71Wh capacity

Batteries (some anyway) have a "minimum state of charge" beyond which you can't discharge without damaging them. This will depend on what tech is used in your batteries. I think lithium doesn't have one, but lead-acid variations do. For some it is as much as 50%, meaning you would only get half of your 71Wh.

 

Unfortunately the Triwave MUST be cooled to -80C to work properly, so I don't have a choice on the matter. I am pretty sure I own a prototype Triwave and the shipping product probably didn't have this limitation.

[Daniel Csati]

Wooow -80C? That is some heavy cooling. I wasn't aware this is possible with stacked Peltiers.

There are other high capacity power banks, a lot of them available in the US, but the next capacity level will add another 2kg weight to the set. It will still fit in a backpack ;)

[Daniel Csati]

28 minutes ago, Andrea B. said:

Wonderful contribution to UVP. Thanks, Daniel !!

Thanks Andrea, I'm glad to be part of UVP. A lot of people with very similar and specific interest. Almost unbelievable

[Stefano]

37 minutes ago, Andy Perrin said:

Unfortunately the Triwave MUST be cooled to -80C to work properly, so I don't have a choice on the matter. I am pretty sure I own a prototype Triwave and the shipping product probably didn't have this limitation.

What happens if you use it at room temperature? Do you get more noise or less contrast?

[Andy Perrin]

Stefano, not even any image. Actually it's kind of neat, as it cools you can watch the noise gradually disappear and the picture fades in! You don't see an image until around -50C though.

[Stefano]

Interesting. I imagine the semiconductors they used are quite unusual, aside from the (unusual) SWIR sensitivity. Some LWIR microbolometer thermal cameras are uncooled and they work well at room temperature, so it must be a weird property of those semiconductors.