Detection, Recognition &
Identification (DRI) Range Calculator

This DRI ranges calculator enables one to easily estimate the maximum range that an object can be either detected, recognized or identified. Upon completion of the calculation, using the final values, you will be able to search for the appropriate IR lens to meet your requirements.

It is important to note that these estimates are based solely on geometrical parameters – the target size, distance, lens focal length and camera detector pixel size. Signal level, detector sensitivity, atmospheric conditions and other factors are not considered!

The calculations used here are based on the “Johnson Criteria”. According to the Johnson Criteria, the minimum resolution, pixels on target, required to achieve a 50% probability for an observer to discriminate an object are:

  • Detection: An object is present – 2 pixels on target
  • Recognition: Discern the type of object, a human vs. a vehicle – 8 pixels on target
  • Identification: Discern specific objects, a man vs. a woman, a car model – 12.8 pixels on target

Calculated DRI ranges are based on the following target size assumptions:

  • The ranges calculated are based on a simplified analysis and are intended for comparative purposes only.
  • Actual range performance of any lens may differ from those shown.
  • The ranges displayed do not imply any warranty on expected performance.

DRI Range Parameters

IR Imaging Lenses

Browse our our long-range LWIR and MWIR lenses or use our IR Lens Finder Tool to find a lens that meets your detection, recognition and identification requirements.

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