Scientists at Michigan State University have dusted off incandescent light bulbs, seeing them as the basis for multispectral machine vision. In nature, light carries much more information about surrounding objects and processes than the human eye can see. Therefore, machine vision should not be like human vision. It should perceive the world more broadly and deeply, making the human environment safer and more comfortable.
Image source: Brenda Ahearn/Michigan Engineering
Sunlight does not have polarization; it can acquire it, for example, by reflection. Reflection from the surface of water, for example, becomes linearly polarized, making polarized light brighter and more harmful to vision. Sunglasses with polarized lenses can easily compensate for such phenomena.
A useful property of polarization is its ability to densify the transmission channel in an optical fiber. For this purpose, circular polarization is used. In nature, insects and some crustaceans see polarized light, which makes them better gatherers or hunters. It is clear that robotics and a number of areas in science will benefit if devices can recognize light in an extended spectrum, including different types of polarization.
Researchers at the University of Michigan have created a nanoscale device made from a tungsten filament that is capable of emitting elliptically polarized light. This phenomenon became possible after the filament was made of such a length that is comparable to the wavelength of light.
Elliptical polarization is an extreme case of both circular and linear polarization, but it can be used on its own for the same purposes of traffic multiplexing on the same optical cable. In the case of machine vision, the use of elliptical polarization makes it possible to increase image contrast, which is necessary for recognition in the dark or in poor lighting.
Finally, elliptical polarization could lead to a variety of medical devices that could help with imaging human tissue samples as well as testing.