The invention discloses a commodity falling detection method of an automatic vending 
machine based on double cameras. The method comprises detection steps that (1) when a facility detects that a usercompletes 
payment, a holder rises to a layer where a commodity is positioned and is stopped, and the cameras at the two sides of the holder are started for snapshot; (2) a local 
processing module of the facility is started to process each snapshot image 
cutting the snapshot image according to a pre-determined 
monochrome chequer position of a side plate of the holder, removing irrelevant areas, graying the 
cut image, carrying out 
edge detection on the grayed image via a 
sobel edge detection operator to generate an edge image, and storing the edge image as a 
background image; (3) after that thebackground is shot, a commodity channel 
conveyor belt is started, and the cameras at the two sides of the holder are started to 
shoot the state of the holder; and (4) the 
conveyor belt is stopped andthe cameras are switched off. The method can be used to detect small, flat and transparent commodities, and influence of the ambient light on commodity detection can be avoided effectively.