Lens and FOV come from the camera datasheet. DORI thresholds: IEC 62676-4:2014.
Field of view and pixel density
The lens sets the angle; distance turns that angle into a scene width. Divide the camera's horizontal pixels by that width to get pixels per meter or foot.
This tool starts from each camera's datasheet field of view at the wide and tele ends, so the numbers match what the manufacturer publishes.
IEC 62676-4 defines four DORI levels by pixel density on the target: Detect 25 px/m, Observe 62.5 px/m, Recognize 125 px/m and Identify 250 px/m.
FAQ
What are the DORI distances?IEC 62676-4 sets pixel densities on the target: Detect 25 px/m, Observe 62.5 px/m, Recognize 125 px/m and Identify 250 px/m (about 7.6, 19, 38 and 76 pixels per foot).
Why does the field of view match the datasheet?The tool uses each camera's published horizontal and vertical FOV at the wide and tele ends, so real lens distortion is included. Between the ends it interpolates the lens's effective image width.
What is pixels per foot?Horizontal resolution divided by scene width in feet. More pixels per foot means more detail on a face or plate.
What if the camera can't reach my target?Reverse mode tells you when the needed focal length is past the lens range and lists catalog cameras that can reach it.
My camera isn't listed. What now?Type the model and it is sent to the catalog team as a suggestion. Pick a catalog model with the same sensor and lens until it is added.