  An experimental procedure for studying soliton gases in shallow water is
devised. Nonlinear waves propagate at constant depth in a 34\,m-long wave
flume. At one end of the flume, the waves are generated by a piston-type
wave-maker. The opposite end is a vertical wall. Wave interactions are recorded
with a video system using seven side-looking cameras with a pixel resolution of
1\,mm, covering 14\,m of the flume. The accuracy in the detection of the water
surface elevation is shown to be better than 0.1 mm. A continuous monochromatic
forcing can lead to a random state such as a soliton gas. The measured wave
field is separated into right- and left-propagating waves in the Radon space
and solitary pulses are identified as solitons of KdV or Rayleigh types. Both
weak and strong interactions of solitons are detected. These interactions
induce phase shifts that constitute the seminal mechanism for disorganization
and soliton gas formation.
