POLKA – Polarization Camera

Fraunhofer Institute for Integrated Circuits

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POLKA – Polarization Camera

An innovative camera for detection and analysis of polarized light

Our POLKA compact polarization camera makes the invisible visible by registering a property of light that is imperceptible to the human eye: polarization. While we perceive the intensity and wavelength of light as brightness and color, respectively, we lack the capacity to detect its polarization. Not so in the animal kingdom: many insects and aquatic animals are able to exploit this information, using it, among other things, for spatial and temporal orientation as well as for locating food and mates.

In industrial environments, the polarization of light contains valuable, if little-used, information. For instance, stress-induced birefringence in glass or transparent plastic is accompanied by changes in polarization. The ability to detect such alterations can greatly aid production monitoring, design optimization and final product inspection. This is where our POLKA camera comes in. Housed in an industrial-strength chassis, it is sufficiently robust to cope with the harsh conditions associated with inspection processes.

What sets this camera apart is its cutting-edge nanostructured CMOS sensor, which was developed by Fraunhofer IIS. It is thanks to this sensor that POLKA is able to collect all the polarization information for each pixel of every frame. At up to 250 frames per second, even fast events can be captured with no motion blur. Using real-time color coding, the dedicated software translates the information collected about the intensity, angle and degree of polarization into a visual display that is accessible to the human eye. By making polarization information visually comprehensible, POLKA adds a new dimension to machine vision.

Specifications

Optical data:

  • Format: 1/5"
  • Resolution: 560 x 256 pixels
  • Pixel size: 6 µm
  • Quantization: 12-bit
  • Polarization extinction ratio: > 100:1
  • Angular resolution: < 0.2 degrees
  • Dynamic range: > 55 dB
  • Recording speed: up to 250 fps

Electrical data:

  • Interface: GigE Vision
  • Control signals: sync/trigger
  • 12-pin Hirose connector
  • Supply voltage: 5 V/5 W

Mechanical data:

  • Lens mount: C mount
  • Dimensions: 55 x 55 x 75 mm
  • Weight: 350 g
  • Fixing: two M4 screws, pre-drilled holes
  • Industrial-strength chassis