STATISTICS OF TELEVISION SIGNALS 



753 



(lit^tancos. This correlation, say, l)ot\vo(Mi horizontally afljoining clomonts 

 is simply the a\'oragc product of the two brightness values of each pair 

 of neighbors, relative to the average square of all brightness values. 



The three quantities enumerated above contain a great deal of sta- 

 tistics in very compact form, but these statistics are essentially of a local 

 and linear nature. They do not include the bulk of the large-scale re- 

 dundancy, which is of a far-flung and nonlinear nature. 



AUTOCORRELATION 



For a fimction of time, f(t), the autocorrelation can be expressed as 



^(r) = WWW) (1) 



Fig. 1 — Picture autocorrelator. 



