Real-time polarimetric imager

There is strong evidence to suggest that polarimetric techniques offer significant improvements in the ability of electro-optic sensors to detect difficult targets in cluttered backgrounds. Many previous attempts to quantify the potential benefits have been hampered by an inability to gather all the polarimetric data simultaneously from a scene. Sequential data gathering can lead to artefacts in the polarimetric data which in turn lead to spurious and erroneous conclusions being drawn This paper describes work undertaken to build and test a pair of four camera, real time, polarimetric sensors that measure all four Stokes parameters simultaneously. One of the sensors operates in the visible waveband and the other in the near infrared. Example images obtained with both sensors are shown, together with measured target and background signal distributions for one of them. Preliminary results from this work show that the sensor can significantly improve target discrimination.