Two-dimensional patterns for optical alignment.
Two-dimensional patterns that have properties suited for optical alignment have been constructed from one-dimensional binary Barker codes. Applications include automated alignment of masks with patterns in photolithography.
Constructing new perfect binary arrays
Only a small number of different sizes are known for which there exist two-dimensional perfect binary arrays. Construction methods are given which generate new two-dimensional perfect binary arrays, four of which are larger than any previously reported.
Two-Dimensional Binary Arrays with Good Autocorrelation
Calabro and Wolf (1968) Inform. Contr. 11 ) investigate the autocorrelation properties of certain periodic two-dimensional arrays. This note points out a relationship between periodic p × q -arrays with two-level autocorrelation and difference sets in the group C ( p ) × C ( q ), where C ( n ) denote the cyclic group of order n . This observation enables us to construct several families of such arrays, some of which are perfect.