说明：  本程序可以由2-D IIR数字滤波器的传递函数求出其冲激响应。通过分析冲激响应确定滤波算法的稳定性，见程序前言给出的参考文献。
(This procedure can be 2-D IIR digital filter transfer function to derive its impulse response. By analyzing the impulse response filtering algorithm to determine the stability of the procedure see references given in the foreword.)