A filter and method of filtering modifies the computation order to accommodate horizontal symmetric filtering, and modifies the source operands while modifying the single instruction multiple data (SIMD) computation, so as to eliminate such heavy overhead of transposing a pixel matrix. The filter and method of filtering reformats the equations involved in the prior art to the following equations, thereby acquiring the interpolation results by reducing the required clock cycles to three cycles: acc=a0*(|p0+p5|p1+p6|p2+p7|p3+p8|) acc=a1*(|p1+p4|p2+p5|p3+p6|p4+p7|)+acc acc=a2*(|P2+P3|P3+P4|P4+P5|P5+P6|)+acc.