How the camera sees a scratch on a cosmetic carton
To see a scratch on a cosmetic carton, a faint scratch needs side light or dark field. Flat light often shows nothing. If you cannot see it, change the light or the resolution first. Do not loosen the threshold first.
To see a scratch on a cosmetic carton, a faint scratch needs side light or dark field. Flat light often shows nothing. If you cannot see it, change the light or the resolution first. Do not loosen the threshold first.
Fix the optics first
A fine bright line in the web direction. The ink film is scraped open. If the picture cannot separate it, loosening the threshold only paints the brand colour red. A faint scratch needs side light or dark field. Flat light often shows nothing.
Optics
| Need | Enough | Not enough |
|---|---|---|
| A faint scratch needs side light or dark field. Flat light often shows nothing. | A fine bright line in the web direction. The ink film is scraped open. | Only a blurred circle left |
| About 3 pixels across | It stays | It comes and goes, and you still write that it can be caught |
| the brand colour in the field of view | The critical place is seen | Only the decorative edge is lit |
Try it on a sample
- Confirm the picture can separate it: A fine bright line in the web direction. The ink film is scraped open.
- Count about how many pixels it covers.
- If you cannot see it, change the light or the focus. Do not change the threshold.
