This report is based on trails where number of trained test persons were given the task of deciding at what level of noise and spatial degradation they could identify fighter aircraft in computer generated images. The test persons gave a confidence level to those answers. This enabled finding the probability of correct identification as a function of noise and blurring. The report shows the results of some 6000 tests with 23 fighter aircraft seen in three different aspects: top, side and front. Chapter 1 of this document is introduction. Chapter 2 gives the theoretical background and the algebraic definitions of the quantities used. Chapter 3 describes the software and the test process used in the tests. Chapter 4 gives the results.