Choosing a Surveillance System: What the Standards Actually Require
“Reliable” is the word every camera brochure uses. Almost none define it. The international standard for video surveillance does define it, and it does so in pixels.
IEC 62676-4 is the application-guidelines part of that standard. It ties four operational goals to four measurable pixel densities on the target. Axis Communications reproduces the table in its white paper on pixel density: detection needs 25 pixels per metre, observation 63, recognition 125, identification 250. The model works back from roughly 40 pixels across a human face, on an assumed face width of 16 centimetres.
That one table settles most arguments about which camera to buy.
Detection and identification are not the same purchase
A camera that tells you somebody is in the yard costs a fraction of one producing footage that identifies who it was.
The gap is ten times the pixel density. Density also falls with distance. A camera hitting 250 px/m at four metres may manage only detection-grade coverage at twenty.
This is why a “4K” badge means little on its own. Resolution, lens and mounting distance together set the pixel density at the spot that matters. That spot is the gate, the till, the loading bay — and that figure is what the standard cares about. Axis also notes that light direction, optics quality and compression all shift the result.
So map the property before shopping. List the points needing identification. List the points where detection suffices. Price them separately. Most buyers over-specify the car park and under-specify the one doorway that would have mattered.
The rules that apply the moment you record a person
Most buying guides stop before this section. They should not.
The European Data Protection Board’s summary of its guidelines on video devices opens by stating that GDPR compliance is mandatory for every organisation using video surveillance. Three obligations bite straight away.
Signage works in two layers. A sign at eye level, before anyone enters the monitored area, carries the purpose, the controller’s identity, individual rights, and where to find the rest. A fuller notice sits at reception or behind a QR code.
Retention has a default that surprises people. The EDPB observes that damage is generally detected within one or two days. A storage period of a few days is therefore often sufficient. Ninety-day retention is not a feature to advertise; it is a decision you have to justify.
The household exemption is narrower than homeowners assume. A domestic camera sits outside the GDPR only while it stays domestic. Point it at the street or across a boundary and the regulation applies to you personally. The EDPB’s own worked example says cameras should film your own premises rather than the neighbouring property or the public area around it.
Large-scale systematic monitoring of a publicly accessible area also triggers a Data Protection Impact Assessment. That has to happen before the system goes live.
Buy for the network you will have in five years
Scalability is not a marketing adjective. It has a technical test, and the test has a name.
ONVIF publishes interface profiles. They let cameras and video management software from different manufacturers work together. Conformance is what you check on a datasheet, because it decides whether you can add a camera in three years without replacing the recorder.
One detail matters more than the profile count. ONVIF has announced the end of support for Profile S, its original 2011 video-streaming profile. The reason is cybersecurity: the authentication mechanisms that profile specifies are no longer consistent with current recommendations. Profile T is the replacement. Profile S carried more than 33,000 conformant devices across fourteen years, so plenty of equipment on shelves still lists it.
Buying Profile S hardware today means buying into an authentication scheme its own standards body is retiring.
Choosing the hardware itself
With pixel targets and profile requirements settled, hardware selection gets much easier.
Outdoor housings carry ingress-protection codes under IEC 60529. The two digits after “IP” rate protection against solids and against water respectively, so IP66 means dust-tight and resistant to powerful water jets. Impact resistance runs on a separate IK scale under IEC 62262. Match both to the actual mounting position rather than the catalogue photograph. A camera tucked under a soffit and one on an exposed gable face very different weather.
Manufacturer choice matters most for firmware. Cameras need security patches for years. A vendor that stops publishing them leaves you running an unpatched Linux device on your own network. Datasheets for mid-market lines like the UNV camera range list ONVIF profile conformance per model, which is the detail worth comparing.
Whatever the badge, two questions decide it. How long will this model receive firmware updates? Which ONVIF profile does it claim?
Where the supply chain becomes a compliance question
Anyone spending public money runs into a rule the brochures skip.
Section 889 of the 2019 National Defense Authorization Act bars federal agencies from buying covered telecommunications and video surveillance equipment. From 13 August 2020 it also bars recipients of federal awards from charging such equipment to those awards. Guidance from the US Department of Labor on how the prohibition works for grants and loans names the manufacturers: Huawei, ZTE, Hytera, Hikvision and Dahua, plus their subsidiaries and affiliates. The covered foreign country is the People’s Republic of China. For grants and loans, unlike procurement, nobody can waive it.
The named list is not the whole rule. Section 889 also reaches entities the Secretary of Defense reasonably believes a covered government owns or controls. Additions appear in the exclusions list on SAM.gov. Compliance can also vary between models inside one manufacturer’s range, so a brand-level answer will not satisfy a contract demanding a specific one.
If federal money touches the project, ask for model-level compliance documentation in writing before ordering.
Installation, and the twenty-minute audit
Placement decides whether any of the above survives contact with the property.
The pixel-density figures assume a camera aimed where you think it is, at the height you specified, with a lens matched to the distance. Getting that wrong costs more detail than any spec-sheet upgrade recovers.
Two habits belong in every installation. Change every default credential before the camera touches the network. Put recording equipment on a segmented network rather than the one carrying office laptops.
Then test it. Walk the perimeter after dark. Check whether you can identify a face at the gate, rather than merely register that a shape passed through. That walk is the only honest audit of a surveillance system, and it takes about twenty minutes.
ONVIF’s decision to retire Profile S signals where this field is going. Interoperability standards are now being revised on cybersecurity grounds rather than feature grounds. A camera bought for its picture can therefore be obsoleted by its authentication. Ask about both before the invoice arrives.
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