What a camera needs to see a dot halo on a food web
You must be able to see the ring of a single dot. Looking only at the solid is not enough. If you cannot see it, change the light or the resolution first. Do not loosen the threshold first.
You must be able to see the ring of a single dot. Looking only at the solid is not enough. 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
The ring of the dot is dark and the centre is light. If the picture cannot separate it at all, moving the threshold only paints the ingredient list and the heat-seal area on the food web as a field of red. You must be able to see the ring of a single dot. Looking only at the solid is not enough.
Optics
| Needed | Enough looks like | Not enough looks like |
|---|---|---|
| You must be able to see the ring of a single dot. Looking only at the solid is not enough. | The ring of the dot is dark and the centre is light. | Only a blurred circle left |
| About 3 pixels across | It shows steadily | It comes and goes, yet you write that it can be detected |
| The ingredient list and the heat-seal area are in the field of view | The critical place is seen | The light only hits the decoration edge |
Try it on a sample sheet
- Confirm the picture can separate this: The ring of the dot is dark and the centre is light.
- Count about how many pixels it covers.
- If you cannot see it clearly, change the light or the focus. Do not change the threshold.
