where vm is the mean vector of a 3 3 vector array: vi is a set of single x vectors within the 3 x 3 vector and i is the running index. array; In the next step we calculated the azimuth of vm and obtained the mean value for the standard deviation. The single differences for the standard deviation between azimuth vi and azimuth vm (M) were defined by a case-by analysis for M <180" (-M) and M >180° (E360 -M). For the STDEV alue obtained we defined a threshold of 20 for the maximum acceptable STDEV value of a 3 x 3 filter panel All other vectors were eliminated. This led to a complete capture of all faulty correlations, but also affected a buffer zone of correct correlations