After the experiments conducted on the data set, engineers from Magenta realized that motion detection is probably the most promising method to detect the cooling water stream flowing out from the stone cut. By applying Fourier analysis, they have been able to recognize the fundamental frequency at which the water flows out of the cut. This will probably be the key feature to exploit in developing a method for the automatic monitoring of the cooling water stream.
In the image below you can see a plot of the frequency spectrum extracted from a small shot from one of the videos in the data set.
Below, an istantaneous plot of a sample frequency spectrum: