Staggered or adapted grids for seismic tomography?

摘要

Often a prisoner can see the sky from jail only through a grid. Thus, the grid may hide the moon or some landscape detail. In this case, he can solve the problem by moving his head just a bit. He will lose some other detail but will see the desired one. Because he remembers details seen before, his mind can reconstruct the image he would get out of the jail— without the grid. Actually, there is another way for reducing the grid annoyance; he could stretch the grid so that it does not hide any interesting view. However, this is more difficult (and less legal) and is usually adopted for other goals (e.g., escapes).