In this letter, we propose a new technique that reduces the computation time to derive the MEI coefficients in solving scattering problems by the Measured Equation of Invariance (MEI) methods. Methods that use the MEI technique spend most of the computation time in the integration process to derive the MEI coefficients. Moreover, in the conventional solution process, some repeated computation of metron fields to derive the MEI coefficients is included. To avoid the repeated operations and thus save computation time, we propose a matrix localization technique in computing the MEI coefficients. The time comparison for the computation of MEI coefficients of a cylinder and a sphere is given to verify the CPU time reduction of our new technique.