SBIR-STTR Award

As discussed in the solicitation for this SBIR, EPAS and other current passive ASW sensors have not yet incorporated the use of polarization analyzers to mitigate the effects of high background clutter their imaging systems. It is postulated that proper use of polarization analyzers can reduce the false alarm rate and improve the probability of detection near the solar glint pattern. It is also possible that the polarization signatures at look angle between 40 and 80 degrees will be useful in detecting other features associated with the presence of a submarine. This proposal leverages a current Advanced Coherent Technologies SBIR which is collecting Stokes Vector imager from the Coronado Bay Bridge. In that effort a four camera / four aperture imaging system is used to collect four polarization channels. The polarization imagery will be used to enhance both wake induced wave slope variations and to reduce near sun glint background clutter which contributes to passive ASW system false alarm rates. The program is utilizing the PAR Government System MANTIS-3T system. A small MANTIS-3T four channel system weighs less than five pound and downlink control and imagery easily using existing relatively low tech communication links. This type of sensor might thus be appropriate not necessarily as a stand alone system in an EPAS concept but as an EO validation sensor / false target reducer for a Digital MAD system. In that application the bulk of the payload is the Digital MAD. As a Digital MAD adjunct sensor the FOV of MANTIS would need to be on the order of 10-30 degrees full angle and operating with four spectral filters. In order to detect others feature associated with a target presence outside of the MAD swath the sensor would need a narrower field of view and a single blue-green band (or even a single red band) used with the Stokes Vector Polarization filters. If the MANTIS could be enhanced such that is could be switched in flight between the two modes without increasing size and weight the sensor would have utility both as a MAD target validator and as a complementary search sensor.

Benefits:
This development will demonstrate and advance the use of small low cost multichannel imaging systems. With channel available to either multiple spectral band, multiple polarization analyzers, or combinations the sensor will have applicablity in search and rescue, harbor security, and environmental monitoring as well as numerous military applications

Several sensor systems are currently under development for use in ‘maritime remote sensing’. Missions such as surf zone and shallow water mine countermeasures, optical ASW, maritime search and rescue, and marine mammal detection and tracking are included in our definition of remote sensing. The optical components of these systems are high end, standard, COTS camera systems designed by industrial camera makers for multiple uses ranging from scientific research (e.g. Astronomy) to machine vision. Thus even though the systems are specifically tailored to the maritime environment, their basic cameras are general in nature. It is the intent of this program to look specifically at each component of a maritime remote sensing system and optimize the use of that component to the maritime environment. Initially, emphasis will be on the camera itself and its associated optics. Special attention will be given to the use of polarization analyzers in improving imaging and detection. To do, this unique attributes of the maritime environment must be identified and exploited in specific system designs to generate superior systems in terms of performance, cost, volume, and reliability.

Keywords:
Multispectral, Polarization, Electro-Optics, Maritime Remote Sensing