What a camera needs to see a void on a corrugated preprint
Paper white and ink must separate, and it stays steady only at about 3 pixels. A steady sight needs about 3 pixels. If you cannot see it clearly, do not loosen the threshold.
To see a void on a corrugated preprint, paper white and ink must separate, and it stays steady only when it spans about 3 pixels. If you cannot see it, change the light or the resolution first. Do not loosen the threshold first.
If you cannot see it, change the optics first
A white spot with a clean edge, and paper or film in the middle. If the image cannot separate them at all, moving the threshold only paints the barcode and the product name solid red. Paper white and ink must separate, and it stays steady only when it spans about 3 pixels.
Optics
| Need | Enough looks like | Not enough looks like |
|---|---|---|
| Paper white and ink must separate, and it stays steady at about 3 pixels. | A white spot with a clean edge, paper or film in the middle. | Only a blurry circle left |
| About 3 pixels across | Shows up steadily | Comes and goes, and you still write that it can be detected |
| Barcode and product name in the field of view | The critical spot is seen | Only the decorative edge is lit |
Try it on a sample
- Confirm the image can separate it: a white spot with a clean edge, paper or film in the middle.
- Count about how many pixels it spans.
- If you cannot see it clearly, change the light or the focus. Do not change the threshold.
