Understanding DORI: How to manage video system expectations with end users

When discussing camera systems with integrators, we commonly hear the question (usually from the end user), how far can that camera see? The answer is more complex than a specific distance as there is a difference between seeing something in the distance and being able to tell who the person is. DORI can help you provide a more nuanced answer.

DORI: Detection, Observation, Recognition, and Identification comes from the international standard IEC/EN 62676-4 “Video Surveillance Systems for use in Security Applications”. It gives installers a shared, measurable way to describe what a camera will see at a given distance, instead of just relying on resolution.

Rather than just relying on resolution, DORI also considers field of view to come up with pixels per foot. It breaks camera performance into four tiers, each tied to a minimum pixel density on the target.

•          Detection (about 7.62 px/ft) only confirms that something, a person or vehicle, is present in the field of view.
•          Observation (about 19.2 px/ft) adds enough detail to note general characteristics like clothing or movement, but not enough to identify someone.
•          Recognition (about 38.1 px/ft) is where someone familiar with a person could plausibly say "that looks like them."
•          Identification (about 76.2 px/ft) is the level needed to positively identify a stranger, typically the standard needed for evidentiary footage.

The table below shows how this plays out in practice. It shows the maximum distance, in feet, at which each DORI tier is met with a typical 4 or 8MP camera across various lens focal lengths. The table below is based on specific Luminys cameras but should work as a relative guide for other brands.

Luminys has started to list DORI distances on their cut sheets for easy access.

Lysora’s cloud CCTV design tool uses DORI shading when showing the field of view of the cameras. The camera on the left is 4MP and the one on the right is 8MP.

Now, when an end user asks you how far a camera can see, you can use DORI to clarify how much detail they are expecting to see so you can manage their expectations and make sure the installed system is exactly what they wanted.