In fact, the biggest disadvantage of AOI is that some shadows are not very obvious, making it easier to make misjudgments. These issues can sometimes be differentiated by varying colors of lights, but the most challenging scenarios involve components concealed by other parts and solder joints located beneath the components. Traditional AOI systems can only inspect areas accessible to direct light, like the gaps in the screen frame or components situated along the edges. Consequently, AOI may fail to detect certain faults and errors.

Furthermore, optical inspection is influenced by variables such as light intensity, angles, resolution, etc. This means that certain shortcomings can only be identified under specific conditions, making it challenging to achieve a 100% detection rate.

While AOI should be capable of identifying incorrect components with varying shapes or distinctive surface markings, it struggles with detecting components without clear visual differences, such as resistors and capacitors smaller than 0402 size. These subtler discrepancies pose difficulties for AOI systems.