What should be detected by visual inspection

What should be detected by visual inspection?

Is it a minute defect that only a skilled inspector can see?

Is it a "somewhat visible" defect?

What we really need to detect is

Functional Defects

Severe defects that lead directly to complaints

Isn't it?

Result of enhanced visual inspection,

Even the smallest defects were found and destroyed,

However, the inability to sustain concentration causes impossible defects to spill out.

It is not the detection capability that needs to be enhanced, but the stability of the detection capability.

The purpose of automating visual inspection is often considered to be "cost reduction,

The ability to continue to inspect all numbers to a stable standard

The ability to increase the percentage of good products by not increasing detection capacity beyond what is necessary.

We believe that a large

So what about the "hard-to-see functional defects"?

Wouldn't it be a mistake to try to address such defects through visual inspection in the first place?