According to the Automated ImagingAssociation (AIA), machine vision encompasses all industrial and non-industrial
applications in which a combination of hardware and software provide
operational guidance to devices in the execution of their functions based on
the capture and processing of images. Though industrial computer vision uses
many of the same algorithms and approaches as academic/educational and
governmental/military applications of computer vision, constraints are
different.
Industrial vision systems demand greater
robustness, reliability, and stability compared with an academic/educational
vision system and typically cost much less than those used in
governmental/military applications. Therefore, industrial machine vision
implies low cost, acceptable accuracy, high robustness, high reliability, and
high mechanical, and temperature stability.
Machine vision systems rely on digital
sensors protected inside industrial cameras with specialized optics to acquire
images, so that computer hardware and software can process, analyze, and
measure various characteristics for decision making.
As an example, consider a fill-levelinspection system at a brewery (Figure 1). Each bottle of beer passes through
an inspection sensor, which triggers a vision system to flash a strobe light
and take a picture of the bottle. After acquiring the image and storing it in
memory, vision software processes or analyzes it and issues a pass-fail
response based on the fill level of the bottle. If the system detects an
improperly filled bottle—a fail—it signals a diverter to reject the bottle. An
operator can view rejected bottles and ongoing process statistics on a display.
Figure 1. Bottle fill-level inspection example
Benefits of Machine Vision-
Where human vision is best for qualitative
interpretation of a complex, unstructured scene, machine vision excels at
quantitative measurement of a structured scene because of its speed, accuracy,
and repeatability. For example, on a production line, a machine vision system
can inspect hundreds, or even thousands, of parts per minute. A machine vision
system built around the right camera resolution and optics can easily inspect
object details too small to be seen by the human eye.
In removing physical contact between a test
system and the parts being tested, machine vision prevents part damage and
eliminates the maintenance time and costs associated with wear and tear on
mechanical components. Machine vision brings additional safety and operational
benefits by reducing human involvement in a manufacturing process. Moreover, it
prevents human contamination of clean rooms and protects human workers from
hazardous environments.
