VIDEO-BASED BREAKWATER OVER-TOPPING MONITORING

Abstract

In recent years, swell-like large wave events have occurred on the east coast of Korea, causing severe breakwater over-topping disasters and dozens of life losses. Breakwater over-topping is mainly characterized by incident waves rather than other physical sources such as tide, currents, etc. A breakwater over-topping monitoring system, developed to reduce coastal damages by the swell-like waves around Korea, was enabled by CCTV imaging and analysis technique. In detail, the CCTV image frame sequences were sampled at 3 Hz during a time period of 15 minutes, and rectified using the surveyed breakwater geometry data, i.e., ground control points. The horizontal waterline oscillations which could be converted to run-up motions using the measured breakwater slope were extracted across the sloped breakwater incline from the rectified image sequences using a line detection method. Characteristics of the breakwater run-ups were analyzed from the time-series of the extracted waterline fluctuations using the spectral analysis method. Comparisons of the run-up and incident wave properties showed that the run-up heights were linearly influenced by the incident wave heights. than other physical sources such as tide, currents, etc. A breakwater over-topping monitoring system, developed to reduce coastal damages by the swell-like waves around Korea, was enabled by CCTV imaging and analysis technique. In detail, the CCTV image frame sequences were sampled at 3 Hz during a time period of 15 minutes, and rectified using the surveyed breakwater geometry data, i.e., ground control points. The horizontal waterline oscillations which could be converted to run-up motions using the measured breakwater slope were extracted across the sloped breakwater incline from the rectified image sequences using a line detection method. Characteristics of the breakwater run-ups were analyzed from the time-series of the extracted waterline fluctuations using the spectral analysis method. Comparisons of