Efficient code constructions for certain two-dimensional constraints

Efficient encoding algorithms are presented for two types of constraints on two-dimensional binary arrays. The first constraint considered is that of t-conservative arrays, where each row and each column has at least t transi tions of the form '0' --> '1' or '1' --> '0.' The second constraint is that of two-dimensional DC-free arrays, where in each row and each column the n umber of '0's equals the number of '1's.