This video, recorded with a smartphone at 60 fps and 1080p resolution, shows Champagne bubbles in a blida glass.
The first difficulty is linked to the small size of bubbles. The second one comes from the bubbles proximity and their high number, up to 150 simultaneously.
The detection and tracking of the Champagne bubbles allows, in a few minutes, to study their size and velocity. The velocity map in fig1 highlights a constant increase of the bubbles velocity, from 5 to about 20 mm/s as indicated on the colorbar, as they go up in the glass along the y axis. The velocity distribution function in fig2 reveals the existence of three populations, slow, fast and faster. Additionally, we determined the area distribution function in fig3. We identify an important proportion of bubbles having an area around 0.2 mm² with a standard deviation of 0.13 mm², resulting in a volume estimate, in the case of perfectly spherical bubbles, of 6.7×10-2 mm3.
The TRACK’s tools, in particular the auto adaptive multi-scale thresholding allows the detection of bubbles in spite of the non-uniform background. The spatio-temporal calibration tool made it possible to study Champagne bubbles with a simple experimental setup in a short amount of time. Moreover, the procedure can be fully automatized to study a video data base.
Fig1) Velocity (mm/s) in a 2D map (mm) of the Champagne bubbles
Fig2) Velocity (mm/s) distribution function of the Champagne bubbles
Fig3) Area (mm²) distribution function of the Champagne bubbles