Birefringence

Residual stress in glass and plastic products can lead to warping, cracking and premature component aging. Imaging birefringence and using it to determine stress in a production environment requires a compact measurement system, high speed imaging and analysis software that can quickly process data.

Traditional methods for measuring birefringence required the use of multiple cameras, one for each direction of polarization. These systems were bulky and difficult to calibrate. Other methods required a single camera and a polarizer that was precisely rotated between several snapshot images. However, this method is too slow to use for capturing dynamic changes to a sample or in high-speed production measurement. By measuring in real time, you are able to create videos of the changes in birefringence while you make fine set screw adjustments.

 PolarCam polarization cameras  measure stress and birefringence in glass, and has multiple applications in machine vision setups. Using active illumination, PolarCam precisely measures and maps mechanical stress in components in real time. Unlike systems which use a single-direction polarizing filter, PolarCam functions independently of the angle of polarization, making it easy to use in production environments where space is at a premium and angles may vary part to part. Because the sensors are compact, PolarCam can be placed where needed for optimal measurement.