  In the present work, we discuss a procedure for constructing sparse binary
and ternary matrices from existing two binary sensing matrices. The matrices
that we construct have several attractive properties such as smaller density,
which supports algorithms with low computational complexity. As an application
of our method, we show that a CS matrix of general row size different from $p,
p^2, pq$ (for different primes $p,q$) can be constructed.
