Peak reading and thresholding in processing radar weather data

A new PPI map is made up of 600 radial lines, each of 100 dots. Each dot is in one of six shades of gray, thus indicating target intensity, and dot size varies somewhat with shade. Each dot combines k independent data 7 to 75, and the data were combined by taking (electronically) the peak reading among the k data. The data from these maps were processed further by counting the fraction of a group of about 20 dots that fell in a given echo- intensity interval. The procedure yields improved intensity resolution, on a scale of intensity level.