CCTV Lens & Pixel Density Calculator
Check the scene width and pixels per metre a camera gives at a distance, and whether it can detect, recognise or identify a person.
From the camera or lens datasheet, at the focal length you will use.
Results
Scene width at that distance: 20.00 m
Pixel density: 128 px/m
Detail level: Recognise
Furthest distance to identify (250 px/m): 5.1 m
Furthest distance to recognise (125 px/m): 10.2 m
Furthest distance to observe (62.5 px/m): 20.5 m
Furthest distance to detect (25 px/m): 51.2 m
Detail levels use the IEC 62676-4 (DORI) pixel-density thresholds. Real results also depend on lighting, lens quality, compression and mounting angle.
How it works
Scene width is 2 x distance x tan(half the horizontal field of view). Pixel density is the camera's horizontal resolution divided by that width. Detail levels use the IEC 62676-4 (DORI) thresholds: 25 px/m to detect, 62.5 to observe, 125 to recognise and 250 to identify; the furthest distance for each level is where the density falls to that threshold.
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