A laboratory study of the 'shoreline' detected in video imagery

A controlled laboratory experiment was undertaken to simulate varying swash zone characteristics and sensor-target geometry found in digital images collected by ARGUS coastal imaging systems. Using a hyperspectral sensor, reflectance data were integrated over the respective red, blue and green wavelengths corresponding to a standard ARGUS video imaging sensor. The dominant swash zone parameters affecting shoreline detection were found to be the presence or absence of surface foam, site-specific sediment characteristics (especially colour), and water depth. Winter versus summer solar elevation and the sensor zenith were also found to affect the cross-shore location of the detected waterline. With this new information, site- and time-specific corrections can be applied to coastal digital imagery, to improve the confidence of shoreline detection