2.2.2. Detection of the Seabed

The sea surface is the cluster with the highest number of photons. It is a high-density group of photons spread over a continuous line, depending on the state of the sea. The sea surface cluster is clearly visible in blue in Figure 2.

According to [17], after removing the noise, the seabed is defined as every signal photon below a threshold value underneath the water surface. Therefore, every photon whose elevation is lower than LMS-3SV (where LMS is the Local Mean Sea level and SV the Surface Variance), was identified as a return signal from the seabed [17].
