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  WEIGHTED AVERAGE

Combines two images (one in the memory), both of which must have corresponding variance estimates, in the ``optimal'' manner of the weighted average. The operation is truly optimal only if the variances are correct and the error statistics are independent Gaussian errors. In practical situations neither of these conditions are likely to be true, but with care in estimating the variances, the results should be statistically better than simple addition.



Andrew Hammersley
2004-01-09