Photonics Spectra Article - Polarization-Based Imaging: Basics and Benefits
July 2016
With spatial correction, line scan polarization cameras detect birefringence, stress, surface roughness, and physical properties that cannot be detected with conventional imaging.
There are three fundamental properties of light: intensity, wavelength, and polarization. Almost all cameras today are designed for monochrome or color imaging. A monochrome camera is used to measure the intensity of light over a broadband spectrum at pixel level1, while a color or multispectral camera is used to detect the intensities of light at the red, green, blue, and near-IR wavelength bands2,3. Similarly, a polarization camera captures the intensity of light at multiple polarization states.
According to a recent AIA market study, worldwide camera sales in machine vision reached $760 million in 2015, with about 80% from monochrome cameras and 20% from color cameras. While polarizers are commonly used in machine vision, until now there have not been line scan polarization cameras that capture images of multiple polarization states.
Polarization offers numerous benefits, not only detecting geometry and surface, but measuring physical properties that are not detectable using conventional imaging. In machine vision, it can be used to enhance contrast for objects that are difficult to distinguish otherwise. When combined with phase detection, polarization imaging is much more sensitive than conventional imaging.
Click here to read the full Photonics Spectra article by Teledyne DALSA's Xing-Fei He.
