Real-Time Polarimetric Imager from 1980s Tech

It’s simple to dismiss many years previous electronics as successfully e-waste. With the speedy developments and plummeting costs of contemporary know-how, most aged is little greater than a historic curiosity at this level. For instance, why would anybody buy one thing as esoteric as 1980-era video manufacturing gear in 2018? An affordable burner telephone might take higher photos, and should you’re seeking to get video in your tasks you’d be higher off getting a webcam or a Raspberry Pi digicam module.

But sometimes the previous methods of doing issues supply potentialities that trendy strategies don’t. This fascinating white paper from [David Prutchi] describes in intricate element how a 1982 JVC KY-1900 skilled video camera purchased for $50 on eBay was turned into a polarimetric imager. The finish outcome isn’t excellent, however contemplating such a tool would usually carry a ~$20,000 price ticket, it’s adequate that anybody seeking to discover the idea of polarized video ought to most likely get able to open eBay in a brand new tab.

Likely many readers aren’t accustomed to polarimetric imagers, it’s not precisely the type of factor they carry at Best Buy. Put merely, it’s a tool that enables the consumer to visualise the polarization of sunshine in a given scene. [David] is within the know-how as, amongst different issues, it may be used to detect man-made supplies in opposition to a pure backdrop; providing a possible methodology for detecting mines and different hidden explosives. He introduced a fascinating talk on the subject at the 2015 Hackaday SuperConference, and DOLpi, his try at constructing a low-cost polarimetric imager with the Raspberry Pi, bought him a fifth place win in that yr’s Hackaday Prize.

While he bought good outcomes together with his Raspberry Pi answer, it took a number of seconds to generate a single body of the picture. To be sensible, it wanted to be a lot quicker. [David] discovered his answer in an unlikely place, the design of 1980’s moveable video cameras. These cameras made use of a dichroic beamsplitter to separate incoming mild into pink, blue, and inexperienced photos; and in flip, every coloration picture was fed right into a devoted sensor by the use of mirrors. By changing the beamsplitter meeting with a brand new 3D printed model that integrates polarization filters, every sensor now receives a picture that corresponds to zero, 45, and 90 levels polarization.

With the modification full, the digicam now generates real-time video that exhibits the angle of polarization as false coloration. [David] notes that the colour replica and backbone is sort of poor as a result of nature of 30+ yr previous video know-how, however that general it’s a good trade-off for operating at 30 frames per second.

In one other current challenge, [David] discovered a strategy to hack optics onto a consumer-level thermal imaging camera. It’s turning into abundantly clear that he’s not an enormous fan of leaving in an unmodified state.

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