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Comment by iamwil | Hacker News Reader

I thought it was going to talk about implementing Compressed Sensing (Compressed Imaging). If you haven't heard about it, you should look it up. It's pretty neat.

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I have spent the last year making a camera that implements exactly a single pixel camera that relies on compressed sensing.

The motivation behind this project is that a professor I am working with had snow melting on his roof. He looked into thermal cameras but found them prohibitively expensive at $4k-$40k. So, we decided to build a cheap camera that only used a single thermal sensor and take the picture as fast as possible.

This camera relies on the fact that many real world images are of the same color (e.g., the sky is mostly blue). It looks for the areas that contain the most detail, the edges, through something called the wavelet transform.

This project sounds very interesting! I'd also love to hear more about any details you make available.

Thanks for the reference to the wavelet transform--it is nice to consider a concrete context where this operation can be employed.

Trouble with single pixel thermal imaging is inertia - thermopiles have thermal mass, you cant take 1000 readings per second, you cant even take 100 readings per second. So while 1 pixel camera in visible light spectrum can work thanks to hi speed acquisition, thermal one will be beyond useless.

not to mention the wave of extremely cheap thermal imagers we got this year -Flir one, seek thermal, all in ~$200 price range.

I'm inclined to believe the FLIR One does not use "true" infrared. There's a portion of the visible spectrum that is nearly IR and it's possible to rely on some IR reflectivity phenomena. I looked at some other FLIR thermal cameras and found them to be much more expensive; thousands of dollars.

However, there's no doubt a small mobile platform is very usable. The primary goal behind this work was not to make a product: it was to provide a proof of concept. We were interested in the image processing and showing that some heavy lifting could be done on a small mobile platform (the Raspberry Pi).

You are correct about the acquisition rate. However, the acquisition rate was more limited by the motors to move the sensor into place.

Flir one is a proper uncooled microbolometer, Flir finally decided to innovate, use modern manufacturing processes/methods and build something cheap to make.

Btw their $4000 E8 thermal camera has VERY SAME components inside (from 320x240 bolometer down to firmware) as $950 E4, only difference is digitally signed config file (that used to be hackable)

Your platform might of been limited by motor speed, but once you reach 10-20 reads per second you will hit a brick wall of thermopile inertia and that will be the end.

Did you make a webpage about the project? I'd like to learn more about your progress.

I do not have a webpage; it's not public yet. This work will be published in February and I'll probably write a corresponding blog[1] post similar to OP's. I'll try and distill the mathematics down while telling a story.

[1]:http://scottsievert.com

Looking forward to it! I'll subscribe on newsblur.

This is the similar project built on top of compressive sensing:

http://dsp.rice.edu/cscamera

We founded InView Technology with a few of the professors heading up Compressive Sensing research at Rice. We make Short Wave Infrared cameras with these techniques utilizing DLP chips. We also sell research platforms.

Our website is a bit thin but we have experience with imaging at XGA and 1080p. The spatial-temporal dimensions of the data with this sensor are quite different from pin-hole FPA imagers. You can trade off spatial resolution and temporal resolution with more freedom than readout ICs. You can also skip the image and go straight to information measurements for pattern/event matching.

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