method of setting a threshold:method='mean' threshold is mean(c(d2arr0, d2arr1)) for both matrices (used as default)
method='imean' setting individual thresholds as mean values
method='imed' setting individual thresholds as median values
method='i1stQ' setting individual thresholds as 1st quartile values
method='i3rdQ' setting individual thresholds as 3rd quartile values
method='isubsd' setting individual thresholds as (mean(d2arrN)-sd(d2arrN))
method='iaddsd' setting individual thresholds as (mean(d2arrN)+sd(d2arrN))
method='med' threshold is median(c(d2arr0, d2arr1)) for both
method='med0' threshold is median(c(d2arr0)) for both
method='med1' threshold is median(c(d2arr1)) for both
method='mean0' threshold is mean(c(d2arr0)) for both
method='mean1' threshold is mean(c(d2arr1)) for both
method='spec' threshold is specified by the 2 numbers of argument trsh individually for matrices