Ask the "field."

It is said that "the illuminator is the deciding factor," but I think it is the visual inspectors on site who know best how to make it easier to see. They probably have considerable know-how.
If it is easy to see with the eyes, it is easy to see with a camera.
The difference is.
The difference is that it is difficult to see while moving the camera, so it is necessary to take a "one-shot" shot.
and
It is difficult to find a defect that happens to light up at a certain angle while moving.
It is difficult to find defects that happen to light up at a certain angle while moving the camera.
The important points are
The important point is that it is difficult to "stably" find defects that happen to light up at a certain angle while the image is being moved.
The defect should be visible on the image.
The image must be bright enough.
The important points are
In short, if you stick to LEDs, you may go down the wrong path.
It is not necessary to use LEDs, but it is a good idea to try with what is close at hand.