Customer would like to detect the presence or absence of transparent films (shrink labels). They detect only transparent films by sensors because the films cover bottles loosely. The bottles stop at the predetermined spot on a line, and the bottles with films can be detected by shielding. After confirming the presence of shrink labels, they heat the bottles and adhere labels to the bottles.
Detecting films stably is difficult because they are transparent. In addition, setting sensors in a narrow space is hard.
Panasonic/Sunx Fiber sensor FX-301 FD-T40 RF-210