Choosing is a subjective matter; or at least how we choose could be the subject of a lengthy philosophical analysis. Perhaps that is why so much of the literature ignores this question. Without any firm theoretical basis, I chose to be approximately the noise level. I estimated this as follows.

The simplest method of choosing is to find the average *v ^{2}* in the plane
and then choose some arbitrary fraction of it, say 10% of the average.
Although this method worked in
Figure 2, I prefer another.
I chose to be the

Notice that Figure 2 uses more initial crosstalk than Figure 1. Without the extra crosstalk I found that the first iteration worked so well, the second one was not needed. Thus I could not illustrate the utility of nonlinear estimation without more crosstalk.

10/21/1998