Detection method of PET bottle cap and liquid level

The invention discloses a detection method of a PET bottle cap and a liquid level. The method comprises steps of: segmenting an interested zone of an image and carrying out pretreatment on the image; carrying out segmentation on a PET bottle body and a background zone; carrying out PET bottle symmetry axis positioning on the image after the pretreatment; and carrying out detection according to the position of the symmetry axis and a line, which a PET bottle adapter ring is on, and coordinates of an adapter ring central point. The method of the invention can carry out real-time ongoing detection on PET bottle cap and liquid level defect on a high speed automatic production pipeline and realize high detection efficiency.