Automated method for tracing shorelines in L-band SAR images

Satellite-based optical imagery has been widely used to evaluate coastal erosion. However, it is difficult to define shoreline edges because the sand under seawater near the shoreline can often be seen in clear water in optical images. Synthetic aperture radar (SAR) images have the potential to be used to interpret the boundary between a sandy beach and seawater because of the unique characteristic of SAR image acquisition. The purpose of the present study is to propose an automated method for tracing shorelines in L-band SAR images. The automated method for tracing shorelines has three steps: 1) detection of shoreline edge detection; 2) masking of unwanted edges; and 3) automated shoreline tracing. To demonstrate the performance of the proposed algorithm a simulated shoreline was obtained from candidate shoreline edge pixels of ALOS/PALSAR amplitude imagery. Results demonstrate that the proposed algorithm can simulate shorelines with a high degree of accuracy while candidate shoreline edge pixels remain nearly unaffected by noise in L-band SAR images.