The A.O.I. test verifies the finished conductor trace image for deviations from the Gerber data and finds errors that the E-Test may not discover, such as (for example) narrowed, but still unbroken conductor traces. 
The A.O.I. test is especially important for the following application areas:
■High frequency
■High power loads
■High data transmission rates
■Op-amps with high amplification factors and input resistances
The inner layers of multilayer boards are checked using A.O.I. before they are pressed together. This guarantees the high reliability of Multi PCB multilayer circuit boards.
Your advantage with Multi CB is that A.O.I. is always included for multilayer boards!
On request, 1 and 2 layer circuit boards can also be tested with A.O.I.
