How DRI Metrics Enhance Camera Performance for Drone-Based ISR Missions

Developer of tethered drone solutions, Elistair, integrates Detection, Recognition, and Identification (DRI) assessment into their rigorous infrared (IR) camera system selection process.

These three benchmarks are essential in evaluating both electro-optical (EO) and infrared (thermal) imaging systems commonly used in Intelligence Surveillance and Reconaissance (ISR) drone systems.

Adherence to DRI standards ensures that these systems deliver optimal performance in real-world ISR operations. In understanding DRI, defense professionals can make better informed decisions, matching camera capabilities with mission requirements.

In their article, ‘How powerful is DRI in drone surveillance?‘, Elistair explains the benchmarks as well as the criteria used to determine them, and how they can be applied for use on UAVs.

What Does DRI Stand For?
DRI is a standardized methodology that quantifies how far an imaging sensor can see—and what it can discern—at various distances. Developed by the U.S. Army in the 1950s, the DRI standard remains a cornerstone for comparing the capabilities of surveillance optics across defense and security applications.

• Detection: The sensor can identify the presence of an object—something that stands out from its surroundings—but cannot yet classify it. For example, a thermal camera might detect a heat signature from several kilometers away.
• Recognition: The system can determine the general category of the object—such as whether it is a person, vehicle, or animal.
• Identification: The finest level of detail, where the sensor can distinguish between specific types of targets, such as a military truck versus a civilian SUV, or a soldier versus a civilian.

How DRI is Determined: The Johnson Criteria
DRI performance is calculated using the Johnson Criteria, a set of thresholds based on how many pixels an object occupies in the sensor’s field of view. These criteria estimate the likelihood that an observer can perform each level of object discernment:

• Detection: 2 pixels on target
• Recognition: 8 pixels on target
• Identification: 12.8 pixels on target

These calculations rely solely on geometric factors—including the target’s size, distance, the focal length of the lens, and the pixel size of the sensor. External influences such as lighting, atmospheric conditions, and sensor sensitivity are not considered in this model, but they can have a real-world impact.

Real-World DRI Ranges for UAVs
DRI values can vary widely depending on the drone platform, sensor quality, and environmental conditions. However, for a high-end EO camera mounted on a professional UAV, typical performance figures for a vehicle-sized object might include:

• Detection: Up to 10 km
• Recognition: Up to 5 km
• Identification: Up to 2 km

These figures may differ based on operational environments and specific sensor configurations.