  The Hadamard matrix with orthogonality is a more important modulation matrix
for computational ghost imaging (CGI), especially its optimized Hadamard
matrix. However, as far as we know, little mention has been paid to efficient
and convenient Hadamard matrix generation for CGI. The existing methods are to
reconstruct any row of Hadamard matrix into two-dimensional matrix and then
optimize it. In this work, we propose a Hadamard `pipeline' coding
computational ghost imaging approach, which can directly generate
two-dimensional Hadamard derived pattern and Hadamard optimization sequence,
whereby both the memory consumption and the complexity of coding implementation
for CGI can be significantly reduced. The optimization method of commonly used
hadamard optimization sequence implementation is also discussed. This method
provides a new approach for Hadamard sequence optimization and ghost imaging
applications.
