Improved Vessel Detection via Quadratic Matched Filtering and Target Parameter Estimation for Dual and Compact Polarimetric SAR

Dual polarimetric (DP) and compact polarimetric (CP) SAR modes are preferred over quad-channel fully polarimetric (FP) modes for wide-area maritime domain surveillance applications because they provide twice the swath width. Recently, the multilook complex (MLC) product was introduced for RADARSAT Constellation Mission (RCM) imagery, which preserves the polarimetric phase information at a considerably lower data volume over the traditional phase-preserved single-look complex (SLC) product. From statistical theory, the optimal detector for polarimetric data has been previously derived and is known as the optimal polarimetric detector (OPD). However, for a deterministic target model, this detector cannot be applied to MLC data and is also impractical, because it requires complete a priori knowledge of the target. Instead, a suboptimal detector, known as the polarimetric whitening filter (PWF), is often used in practice. This letter proposes a new detector called "quadratic matched filter (QMF)" for CP and DP data that can be applied to MLC products for improved vessel detection over the PWF. A technique to estimate target parameters at processing time is also proposed, which can be used to estimate target parameters for both OPD and QMF. The feasibility and improved performance of the QMF detector are demonstrated through simulated receiver operating characteristic (ROC) performance analysis, and by demonstrating detection performance on an image acquired by RCM. It is shown that the QMF provides approximately 1.5 and 3 dB improvement in signal-to-clutter-plus-noise ratio (SCNR) and peak-signal-to-clutter-plus-noise ratio (PSCNR), respectively, over PWF.