In-Circuit Test is the best method for ensuring solder joint connections. It is a much more reliable than AOI. An ICT machine can ensure solder connections are made for array package devices such as BGA, PGA, etc... AOI is best for component I.D.- is there a component there, is it the correct component and is it in the correct orientation. That is for those components with markings. Many small packages do not, so there ICT has the advantage.
There are flying probe ICT machines that have AOI options. The concept here is that you ICT all your passives and AOI your ICs or any other component that cannot be electrically measured accurately. Flying probe ICT w/ AOI option is the best method for MDA (Manufacturing Defect Analysis) in my view because it gives more coverage, you can electrically test components with no markings to ensure they are correct. Of course some capacitors cannot be measured reliably, like filter caps, so in that case you can use the AOI option to at least confirm there is a capacitor there.
One flying prober is the Pilot from Seica- Italy, http://www.seica.com
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