Gauging with Machire Vision has been around since the early days of applications of that technology. With steady improvements in solid state sensor technology and sub-pixel software algorithms, Machine Vision can now challenge and eff6:tively replace some of the more traditional contact/air gauges for both off-line and on-line applications. On-line gauging with Machine Vision offers perhaps the largest potential since it provides the advantages of a non-contact gauging process for 100 percent inspection and the flexibility and data manipulation capabilities of Machine Vision for true in-process control. This can mean a process is monitored more closely to prevent manufacture of "bad" parts as opposed to inspecting for bad .)arts only after manufacture. This paper will examine some of the fundamental issues of Machine Vision used as a non-contact gauge, with definitions of the terminologies commonly used. Special emphisis is placed on the optical issues for on-line gauging applications.
"Fundamentals of on-line gauging for machine vision", Proc. SPIE 1395, Close-Range Photogrammetry Meets Machine Vision, 13952M (1 August 1990); doi: 10.1117/12.2294337; https://doi.org/10.1117/12.2294337