Nozzle line indicated by white rope on the water surface
Flow direction: bottom left to top right

vr: 0.32 m/s
number of nozzles: 5

Distances:
        a: 6.9000
        b: 12.1600
        c: 12.8500
        d: 14.6000
        e: 12.8600

As argued in the article, this set-up (especially the location of the camera) is just within the limits of what is possible with this method. However, the five locations of surfacing air bubble are recognizable. Note that the reference points should be maked at water surface level: in some cases this is below the the midpoint of the base of the trafic cone, instead of at this midpoint (in this case it's more important that the processing is done by someone who was in the field and has experience with recognizing surfacing bubbles).