To　build　a　stiffness　filter　function,　the　homogenization　method　is　adopted　to　compute　the　cellular　equivalent　stiffness　for　square　hole　of　various　size.　According　to　the　discrete　values　obtained,　the　normalized　least　square　method　is　applied　to　fitting　the　equivalent　stiffness　coefficients.　With　these　coefficients,　the　least　square　method　is　used　once　again　to　fit　the　power　exponent　of　the　filter　function　for　the　ICM　(independent,　continuous,　mapping)　method.　The　obtained　filter　function　reflects　correctly　how　the　equivalent　stiffness　varies　with　the　size　of　square　hole.　Moreover,　the　obtained　power　exponent　agrees　with　the　published　empirical　value.