I was not sure what to call this article. I first thought it should be titled, “Why The Johnson Criteria is Wrong.” We use this criterion to predict how far away we can see something using a specific camera and lens. The criteria define the threshold for detection, recognition, and identification (DRI). The industry has used this criterion since World War II. It has not been updated to reflect today’s technology and resolution requirements.
Resolution required for Recognition, Detection, Identification depends on the type of camera
By Bob Mesnik
There is some confusion in the industry about how much camera resolution is required to detect an object, recognize the type of object, or identify exactly what or who it is. The criteria are different between thermal and optical cameras. Resolution for thermal cameras and optical IP cameras are measured differently.
For example, when defining the performance of a thermal camera we use the Johnson Criteria of “detection”, “recognition” and “identification” (DRI).
On the other hand, IP camera resolution performance is usually defined by the number of pixels in the sensor, and we are usually interested in the ability to identify a person.
How much resolution do you need? This article compares how resolution is defined using thermal and optical technologies.