surface wave signal (Figure 23). To prevent the light refraction through the
water column and to increase the strength of the desired signal, SphericelTM
hollow glass spheres were distributed throughout the water column (Figure 24).
The spheres have the appearance of a white powder and a range of specific
gravity of 0.1-1.5 g/cc. During wave generation, distribution of white
pigmentation in the water column remains well mixed.
Chapter 5 Video-Based Wave Direction Measurement