Augmenting Human Vision With Polarimetric Cameras:
Light is just a wave, and the wavelength of light determines its color and determines if it can cook food like microwaves, or if it can see through skin like x-rays. There’s another property of waves human’s don’t experience much: polarization, or if the light wave is going up and down, side to side, or anywhere in between.
[David Prutchi]’s project for the Hackaday Prize was like many projects – a simple, novel idea that’s easy and relatively cheap to implement.
It’s a polarimetric camera meant to see what humans can’t. By seeing the world in polarized light, the DOLPi can see landmines, cancerous tissue, and air pollution using only a Raspberry Pi and a few Python scripts He gave a talk at this year’s
Hackaday SuperConference about polarization cameras and the DOLPi project. After enjoying the video, join us after the break for more details.
While cameras and the human eye can see different wavelengths or colors of light, they can’t easily detect polarization. [David] did remind us that the human eye is capable of detecting polarization, due to a phenomenon called
Haidinger’s brush. He did, however, challenge everyone to tell the difference between two pieces of polarizing film. No one took him up on that challenge.
While traditional cameras and the human eye can’t easily see polarization, bees use polarization to find flowers, and cuttlefish use polarization to find prey. The uses for a polarization camera range from finding landmines, seeing underwater, detecting cancerous tissue, and seeing airborne pollutants. It’s a fascinating range of uses from something as simple as a cell phone camera, servo, and a few sheets of polarization film, and DOLPi makes it real.
A car, as seen with polarized light mapped to colors
The hardware part of the DOLPi is actually pretty simple – it’s really just a Raspberry Pi, camera module, and either an electro-optic polarization modulator (somewhat pricey), or a servo and paper disk with sheets of polarization film taped on at different angles (very inexpensive).
On the software side of things, [David] has a Raspberry Pi take a picture with a camera module, change the polarization filter, take another picture, and eventually combine all of these images into a false-color image with different colors mapped to different polarizations of light.
It’s a relatively simple project – anyone can build a polarization camera and run a few bits of software. But it has the potential to make a huge impact with a lot of great humanitarian uses, seeing things the human eye cannot.
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