Underwater partial polarization signatures from the SHallow water Real-time IMaging Polarimeter (SHRIMP)

Research has shown that naturally occurring light outdoors and underwater is partially linearly polarized. The polarized component can be combined to form an image that describes the polarization of the light in the scene. This image is known as the degree of linear polarization image or partial polarization image. These naturally occurring polarization signatures can provide a diver or an unmanned underwater vehicle with more information to detect, classify and identify threats such as obstacles and/or mines in the shallow water environment. The SHallow water Real-time IMaging Polarimeter (SHRIMP), recently developed under sponsorship of Dr. Tom Swean at the Office of Naval research (Code 321OE), can measure underwater partial polarization imagery. This sensor is a passive, three-channel device that simultaneously measures the three components of the Stokes vector needed to determine the partial linear polarization of the scene. The testing of this vector has been completed and the data has been analyzed. This paper presents performance results from the field-testing and quantifies the gain provided by the partial polarization signature of targets in the very shallow water and surf zone regions.