Fixed.
Bolted to structure above or beside the door. It sees the same frame every shift, so a read failure starts telling you something about the labels instead of the camera.
Reference · Camera scanning
Camera barcode scanning at the receiving door.
Most guidance on camera barcode scanning is about picking a camera. This one is about the twenty feet in front of it: where cameras go at a receiving door, how far and wide they see, what lighting and motion do to a read, and what happens when a label is torn, wrapped over, or doubled. It assumes single-SKU pallets and stays vendor-neutral throughout.
Placement in the flow
The read happens once, at the point the pallet is already moving.
The dock door is the natural read point: every unit passes through it once, in roughly the same place, at roughly the same speed. A read taken there is unambiguous about which trailer a unit came from. A read taken later, after pallets are staged and re-sorted, has to be reasoned back to a trailer, and that's exactly the reasoning that falls apart when a shortage is disputed months later.
A camera read also produces the frame it was decoded from, so the label and its condition are captured as a side effect of scanning rather than an extra task. For the workflow this sits inside, see dock door scanning and warehouse receiving automation.
Three setups
Fixed, mounted, and handheld each solve a different receiving problem.
Mounted.
Rides on a forklift mast or a conveyor frame. It gains reach and loses repeatability, and earns its place where units don't pass a common point.
Handheld.
The exception handler: the inner label on a double stack, or a unit pulled aside for inspection. It catches what the fixed camera can't, but it doesn't replace it.
Camera imagers scan both linear and 2D barcode types. For which ones show up on inbound pallets, see the barcode and label cheat sheet.
The four field variables
Four things decide whether a label reads. Only one of them is the camera.
Field of view.
The frame has to hold the whole barcode and its quiet zone, or there's no read. Cover the full door opening at label height, since label position is the one thing suppliers won't hold constant.
Distance.
Working distance and resolution trade against each other. The narrow-bar width on the smallest label you actually receive sets the limit, not the pallet label alone.
Lighting.
Backlighting turns the frame to silhouette; glare off wrap or a glossy label washes out the bars. Both are fixed by moving the camera or the light, not by adjusting settings.
Motion.
A pallet crossing on a forklift smears the bars during exposure. The fix is a shorter exposure, which means more light at the door.
Exceptions at the door
Design for the labels that fail. Some of them will.
No read. Torn, smeared, or turned-away labels happen. The unit keeps moving, someone keys the number in, and the miss gets logged as an exception, not dropped.
Partial read. Worse than no read, because it can look like success. Verify against the advance ship notice, since a code that decodes but matches nothing is a signal, not noise.
Two labels in one frame. Prefer the code matching an expected value, then the largest and most centered. Anything ambiguous goes to a person, not a guess.
Duplicate reads. A pallet that pauses and comes through twice should be received once. An SSCC already read on this trailer is the same pallet, by definition.
Covered labels. Stretch wrap is the most common cause of a marginal read. It's a supplier conversation that goes better with a picture attached.
For how to write the exception up so it stands later, see receiving discrepancy documentation.
From frame to record
A read is data. A read with its picture is a record.
The value of camera scanning isn't that a camera can decode a barcode. Handhelds have done that for decades. It's that the decode and the image come from the same moment, so the record of what arrived includes what it looked like when it did.
That only holds if the pairing is structural, not assembled afterward: the decoded value, the image it came from, the door, and a capture time set by the device and never edited. Keep the raw frame, not just a crop of the barcode, since the wrap and the stacking around the label are where the useful detail lives.
For what makes a receiving record hold up, see the receiving record.
Common questions about camera scanning.
Where should cameras be placed at a receiving door?
Fixed to structure above or beside the door opening, aimed slightly downward and inward so the frame covers the full opening at label height without looking into daylight. Every unit passes that point once, which is what makes the read unambiguous about which trailer it came from.
Can cameras read GS1-128 labels on moving pallets?
Yes, within limits set by light and speed. Motion during the exposure smears the bars, so a moving read needs a short exposure, and a short exposure needs dedicated illumination near the camera rather than better specifications.
How should poor lighting at the dock be handled?
Treat it as geometry first, settings second. Backlighting turns the load to silhouette; glare off a glossy label or its wrap washes out the bars. Both are fixed by moving the camera or the light, not by adjusting exposure.
What should happen when a camera captures two labels?
Follow a written rule, never a guess: prefer the code that matches an expected value from the advance ship notice, otherwise the largest and most centered code, and send anything still ambiguous to a person as an exception.
Fixed cameras at the door are exactly this.
Flowtally puts a camera on the inbound door and reads the label as the pallet crosses. The read triggers the photo, so the picture and the number come from the same moment, with the door and the exact time attached. Nobody adds a step, and the images are stored securely, exportable on demand.