Applicative Framework for End-to-End AOI Implementation
Figure
3-2 : AOI device installed on the assembly line . A graphical representation of the line layout ( left ) with specific focus on the standalone structure ( bottom left ) and a real image of the vision system ( right ).
On the shop floor , dedicated operators move material from the supermarket to the assembly line . Rotors are neatly placed inside boxes and arranged on a gravity roller conveyor . The vision system analyzes the first box , which is then moved to the picking position if no misplacement is detected . To avoid interference between the operator and the field of view of the AOI camera , the detection system is placed above the box prior to the one in use .
When a new rotor box arrives at the control position , a dedicated sensor , connected to the digital input module and monitored through the Input / Output coordinator , sends a signal to start a new cycle . More in detail , the sensor detecting the presence of the box sets the Boolean variable of the dedicated Input module channel from 0 , indicating absence , to 1 , standing for presence .
The Input / Output module operates on a simple difference between the previous and the current state of the sensor : a non-negative result means that no new box has arrived , while a negative value states for a new box to be analyzed . When it occurs , the Input / Output coordinator sends a signal to the camera through the output module , triggering the acquisition of a new frame that is saved in a dedicated pc local folder . At this stage , the Image Processing module analyzes the image in two steps :
IIC Journal of Innovation 11