Problems

At this preliminary stage there are still some problems to overcome. The separation technique is much more reliant on a stable filter than the interpolationCrawley (1999) or feature identification problemBrown and Clapp (1999). Some preliminary work on filter stability was done in Sava et al. (1998); Sava and Fomel (1999), but the problems associated with non-stationary filters are only beginning to be addressed Rickett (1999). To be effective in 3-D, the problem of spatial aliasing has to be dealt with.