LIEMKE Thermal Performance App

With our thermal performance app you can calculate simple and fast the performance key figures of a thermal imager.
After input the basic key parameters such as pixels, pixel pitch, focal length and object distance, our app outputs the relevant FOV and performance range figures.
The calculations used here are based on the "Johnson Criteria" which were developed many years ago by John Johnson, a scientist at the US Army Night Vision Lab (Night Vision & Electronic Sensors Directorate). According to the Johnson Criteria, the minimum resolution (pixels on target) required to achieve a 50% probability that an observer can discriminate an object at a certain range to the specified level are:

(Reference object: Human with 1,8m height, 0,5m width)

Detection - an object is present: 2 pixels
Recognition - the type object can be discerned, a person vs. a car: 8 pixels
Identification - a specific object can be discerned, a woman vs. a man : 15 pixels