How the camera sees a doctor-blade line on a pharmaceutical label
To see a doctor-blade line on a pharmaceutical label, a faint line needs side light. Flat light is too even, and you will not see it. If you cannot see it, change the light or the resolution first. Do not loosen the threshold first.
To see a doctor-blade line on a pharmaceutical label, a faint line needs side light. Flat light is too even, and you will not see it. If you cannot see it, change the light or the resolution first. Do not loosen the threshold first.
Fix the optics first
A fine line in the web direction. Its place does not move with the image. If the picture cannot separate it, loosening the threshold only paints the legal text and the barcode red. A faint line needs side light. Flat light is too even, and you will not see it.
Optics
| Need | Enough | Not enough |
|---|---|---|
| A faint line needs side light. Flat light is too even, and you will not see it. | A fine line in the web direction. Its place does not move with the image. | 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 legal text and the barcode 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 line in the web direction. Its place does not move with the image.
- Count about how many pixels it covers.
- If you cannot see it, change the light or the focus. Do not change the threshold.
