redzilla
CCTV

CCTV Lens & FOV

Enter the distance to the target, the sensor, the focal length and the horizontal resolution and get the HFOV, the scene width, the px/m and the DORI level (EN 62676-4) reached, with the maximum distance for detection, observation, recognition and identification.

m

Active-area width of the sensor, in millimetres.

mm

Image width in pixels. With MP the width is estimated from a 16:9 aspect ratio.

Examples
redzilla.cl — cctv
 
Field of view (HFOV)
horizontal angle
Density at the distance
pixels per metre
DORI level reached
at the entered distance
HFOV
Scene
px/m

Maximum distance per DORI level

LevelThresholdMax. distanceStatus at D

Status at D shows whether the threshold of each level is met at the entered distance.

How it is calculated · FOV, px/m and DORI (EN 62676-4)

1. Horizontal field of view: HFOV = 2·atan(sensorW / (2·f)) · 180/π, with the sensor width and focal length in mm.

2. Scene width at distance D: width = D · sensorW / f (in metres, with D in metres).

3. Density: px/m = horizRes / scene_width. More pixels on the target means more detail.

4. DORI thresholds (EN 62676-4, px/m): Detection 25, Observation 63, Recognition 125, Identification 250.

5. Maximum distance for a level: Dmax = horizRes · f / (threshold · sensorW). Up to that distance the required density is kept.

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