A camera covering the whole gate for general security and a camera reading number plates are different jobs, and a single camera trying to do both usually does neither well. This is the most common disappointment we are called out to fix on industrial gates.
Why a general-view camera cannot read a plate
A wide-angle camera positioned to see the whole vehicle, the driver and the surrounding area spreads its resolution across a large scene. The plate occupies a small fraction of that frame, and once compressed for recording, the characters blur below a readable size. This is a physics limitation, not a settings problem - the camera is doing its actual job, which was never plate-reading.
Reading a plate reliably needs a camera whose entire frame is dedicated to the vehicle’s approach path at the plate’s height, not a wide shot that happens to include the plate somewhere in it.
The angle that actually works
The camera needs to face the vehicle nearly head-on, angled so the plate is close to perpendicular to the lens. A camera mounted high and angled steeply down - the common placement for general deterrence - views the plate at a slant that distorts the characters and defeats even a high-resolution sensor.
Mount lower than the instinct suggests, closer to number-plate height, and position it to catch the vehicle as it slows or stops at the barrier rather than while still moving at speed. A stationary or slow-moving vehicle at the barrier gives the camera its best chance regardless of format.
Lighting decides this more than the camera does
Headlight glare at night is the single biggest cause of unreadable plates in installations we inspect. A camera facing oncoming headlights either blows out to white or drops the plate into silhouette, and no amount of resolution recovers detail that was never captured.
The fix is positioning the camera so headlights do not point directly into the lens, combined with a camera specified for wide dynamic range if headlight exposure cannot be avoided entirely. During the day, avoid backlighting the plate against open sky, which silhouettes it the same way indoors.
Weighbridge positioning specifically
A weighbridge camera has an advantage general gate cameras do not: the vehicle is stationary and its position on the platform is predictable, which makes a purpose-built plate camera far more reliable than at a moving gate. Position it to capture the plate at the point the vehicle settles on the platform, ideally paired with a second camera covering the driver and cab for the same event, so the weight record, the plate and the driver identity all correlate to one timestamp.
This pairing is what actually closes the loop on stock movement disputes - a weight on its own proves nothing about which vehicle or which driver it belonged to.
What to specify for a plate-reading camera
- A camera dedicated to the plate-reading job, separate from the general gate-view camera
- Mounting height and angle matched to where vehicles actually stop, not a generic recommendation
- Wide dynamic range or an equivalent feature, specifically for headlight handling if the position cannot avoid oncoming light
- Resolution and lens combination tested against your actual plate size and typical approach distance, not a spec sheet number alone
- A recorded test at night before the installation is signed off, not just a live-view check in daylight
Common questions
Do we need a specialist ANPR camera, or will a good CCTV camera do?
For occasional manual review of recorded footage, a well-positioned standard camera with the angle and lighting handled correctly is usually sufficient and considerably cheaper. Dedicated ANPR cameras with automatic plate recognition make sense when you need real-time automated matching against an approved list, which is a different requirement from simply being able to read a plate on playback.
Can one camera cover both plate reading and general gate security?
Rarely well. The angle and framing that reads a plate reliably is usually too tight to also cover the driver, the surrounding area and general activity at the gate. Two cameras doing one job each, at a modest extra cost, consistently outperforms one camera trying to do both.
Why does our plate camera work fine during the day but not at night?
Almost always headlight glare or insufficient light at plate height. Daytime testing alone misses this entirely, which is why any plate-reading installation should be tested and recorded after dark before being signed off, not just checked on a daytime live view.