Researchers with Harvard University’s John A. Paulson School of Engineering and Applied Sciences (SEAS) have published a study detailing the creation of a tiny camera that presents the world as it is seen by some insects and shrimp—polarized. Whereas humans are unable to see polarization, some tiny creatures are able to, an experience replicated by Harvard researchers with a small, portable camera.
Put simply, polarization is the direction in which light vibrates, the result being a shimmery rainbow appearance that, as the video above shows, reveals details about objects that can’t be seen with the human eye. An otherwise invisible defect in a piece of clear glass or plastic, for example, may be readily apparent when viewed with polarization.
A small number of cameras are currently available on the market that can see polarized light, but they come with multiple downsides, including high cost, bulkiness and typically the inclusion of moving parts. These cameras are used in select industries for specialized tasks, such as detecting the presence of material stress or small scratches and dents in a surface.
The Harvard team developed an alternative polarized camera that eliminates these issues; it is described as ‘about the size of a thumb,’ though adding a protective case and lens increases the total size to that of a ‘lunch box.’ The final product can view polarized light and was tested in various ways, including to detect defects in injection-molded plastics.
Though polarized cameras could be useful in a variety of industries and situations, the size and cost constraint limited how widely the technology could be deployed. That changes with the Harvard team’s innovation. Study co-author and SEAS postdoctoral fellow Paul Chevalier explained:
‘Polarization is a feature of light that is changed upon reflection off a surface. Based on that change, polarization can help us in the 3D reconstruction of an object, to estimate its depth, texture and shape, and to distinguish man-made objects from natural ones, even if they’re the same shape and color.’
The compact polarized light camera may one day be used in drones, self-driving cars and even commonly available consumer technology like smartphones.