Figure 1

(a) The high-speed camera (Phantom v2512) near the furnace to visualize the process, (b) a schematic representation of the experimental setup including 1—electrode, 2—ingot, 3—base plate, 4—inspection glass, 5—high-speed camera, 6—lens, 7—circular polarizing filter, 8—computer with camera control software. X, ϕ, and SP denote the gap, the camera angle to electrode surface plane, and sensor plane, respectively.