Polarimeric SAR Ship Detection Based on Sub-Look the Decomposition Technology

In the past few years, polarimetric synthetic aperture radar (PolSAR) as an advanced technology has been widely exploited to Earth observation, among which ship detection is an active research topic. Taking the sub-look decomposition technology as the basic, this paper proposes a new ship detection method abbreviated to ASM. In brief, two single-look complex (SLC) imagesI1andI2are first obtained from the original PolSAR imageOfor forming the data group {I1,O,I2}. Then, theH/A/α decomposition is performed on {I1,O,I2} so as to yield theH/α plane group {P1,P0,P2}, which is subsequently used to suppress sea clutter and generate another filtered data group {F1, F0, F2} that respectively corresponds toI1,O, andI2. Thereafter, a new 3×3 spatial-spectral coherence difference matrix [ST] is further constructed by {F1,F0,F2}, wherein the spatial and spectral information are simultaneously used. Therefore, [ST] can effectively highlight ships from sea clutter. To verify this point, an amplitude-based ship detection metric (ASM) is finally built through multiplying the amplitude values of the termsST13,ST23, andST33together. Extensive experiments demonstrate that, i) [ST] is more appropriate for ship detection than [T]; ii) ASM has a better ability to improve ships’ target-to-clutter ratio (TCR) in comparison with other state-of-the-art (SOTA) methods. Last but not least, experimental results also show that, the detection performance of ASMR(i.e., calculating ASM along the range direction) is similar to that of ASMA(i.e., calculating ASM along the azimuth direction). For example, the average TCR values of ASMAand ASMRare respectively 7.5 dB and 7.06 dB higher than the second place. So, this means the frequency characteristics of ships should be considered into the practical detection process as well.