The Teledyne DALSA Piranha4 Polarization is an industry grade line scan camera tailored to applications which require extended detection capabilities.
Polarisation imaging significantly enhances the detection potential in many demanding applications and is becoming the next generation technology in machine vision. It offers numerous benefits, not only detecting geometry and surface defects, but measuring physical properties that are not detectable using conventional imaging.
Advantages of the Teledyne DALSA Piranha4 Polarization
While standard monochrome and colour cameras record intensity and wavelength, the Piranha4 2k Polarization camera captures intensities of multiple polarisation states. This renders polarisation imaging much more sensitive. It enables acquisition of contrast rich images to detect nonvisible properties such as birefringence, stress, film thickness, and surface roughness. Therefore it's particularly suited for objects that are difficult to distinguish otherwise. Costly and complex hardware solutions can be avoided by using a polarisation camera as part of a conventional imaging setup. The integration of polarisation imaging allows the improvement of the overall production reliability and quality of customers.
The Piranha4 Polarization camera is equipped with a micropolariser on the focal plane of its CMOS sensor to detect different polarisation states. With a maximum line rate of 70 kHz, the camera delivers high speed imaging of 0°(s), 90°(p), and 135° polarisation states and an unfiltered channel. This camera solution is much faster than other polarisation filter technologies, e.g. a rotating or modulated polarisation element. As a result, this technology is ideal for compact, robust and low-cost designs.
While being able to integrate the latest imaging technology, the system can still be designed and supported easily. As the camera is implemented with well established machine vision standards such as CameraLink and GenICam, no custom integration is necessary.
Why polarisation is superior to conventional imaging
Light has three fundamental properties, i.e. intensity, wavelength, and polarisation. While standard monochrome and colour cameras record intensity and wavelength, the Piranha4 Polarization camera captures intensities of multiple polarisation states. This provides valuable additional information that otherwise remains undetected. By using a nanowire array acting like a filter in front of the sensor, only light oscillating perpendicular to the nanowire can reach the sensor in a given position.
The Piranha4 Polarization can be used in either transmission or reflection based configurations. Both approaches require a polariser to convert unpolarised light of an illumination device to linearly polarised light. Physical changes of an object (scratches, coating, stress) alter the polarisation state relative to other zones on the object. This change can be detected by the 3 different polarisation states of the camera.
High contrast images can be achieved by using the reflection based configuration. Here, the angle of incidence is chosen close to the Brewster’s angle of the material and the difference between the reflectance of the s-polarised state and p-polarised state is maximized. This results in a very high sensitivity. Any deviation on the surface due to defects or impurities will result in a bright region.
- Sensor length: 28.8 mm
- Resolution: 4 x 2048 pixels
- Line rate: 70 kHz maximum
- Pixel size: 14.08 µm
- Polarization principle: lines with 0°, 90°, 135° polariser and one line without filter
- Features: multiple region of interest for calibration and data reduction, sub-pixel spatial correction, horizontal parallax correction
- Interface: CameraLink, graphical interface or GenICam compliant configuration applications
Markets and Applications
- Stress identification on parts in industrial automation
- Roughness and scratch detection in surface inspection
- Contrast improvement in food inspection
- Solder joint inspection in PCB-AOI (automated optical inspection)
- Exciting of flourescence substances in biomedical applications