We were running the system at a meat processing plant. The system created false event cards about crates on the conveyor and on tables. The head of HACCP rejected them. Honestly, we were wasting the reviewer's time.

We limited detection to a manually drawn floor zone, and that class of false cards stopped. A crate counted only when it was in the marked floor zone. On each camera we drew that zone by hand. It covered the part of the frame that really is floor, without tables, conveyors and walls.

What we agreed before writing code

We sat down with the head of HACCP first and settled what counts as a violation. A crate directly on the floor is one. A crate on a pallet, trolley, pallet jack or stand is normal. A crate on a conveyor or table is normal too, because it is outside the zone.

Hidden supports and crates put down for a few seconds caused trouble. If a person or another crate hides the support, the system says "undetermined" and does not guess. If someone puts a crate down for a few seconds to open a door or get a better grip, there is no card. The crate has to stay in the zone for a set time first.

Order No. 590 on HACCP procedures requires, in clause 2.4, that food be protected from contamination. The floor gets washed, but it is still the dirtiest surface in the room. People walk on it and pallet jacks drive over it. A crate of raw meat put down there carries that dirt to the table as soon as it is lifted.

This is easy to miss on a walkthrough. A crate goes down "for a minute" because the pallet is taken or the trolley has left. An hour later there is a stack around it. One of the first confirmed cards for this rule showed exactly that: a stack of red crates directly on concrete.

Other mistakes

The system also had trouble seeing small crates from cameras mounted high under the ceiling. We tuned the system for the cameras in that production area; on other cameras this would need to be done again.

Another mistake was in our own numbers. The first accuracy figures looked good. Then we checked and saw that the test frames were too similar to the ones the rule was tuned on, so the result was overstated. That is why we do not quote accuracy for this rule until it has been tested on new days, including the awkward cases: a crate on a trolley, on a pallet, right at the edge of the zone.

What the camera cannot see

It cannot tell what is inside a crate. Product, empty containers or waste all look like the same crate. So zones and exceptions have to match the plant's own rules, for example if empty containers may stand on the floor next to the washing station. It also does not check whether a pallet or trolley is clean, and it sees nothing behind a column, under a table or in a blind corner.

For a new camera, we first run the rule in shadow mode and review its false cards.

https://duovision.com.ua/en/resursy/yashchyky-na-pidlozi/

Written with AI assistance from our own published notes.