好的内插模板是放大后图像失真小的关键。全相位数字滤波器是一种新型的线性相位滤波器。依据全相位滤波理论，提出了2维Walsh内插模板，采用先对角线内插，再水平垂直内插的放大方法。将该方法同最近邻内插、双线性内插、三次样条内插进行了比较，实验结果表明，该方法计算简便，抗噪能力强。

Choosing a good Interpolating template is the key to better recover the subsampled image with low distortion. The All Phase Digital Filter is a new type of linear phase filter. According to All Phase theory, we propose 2-D Walsh interpolating template. Here a newmethod is applied: first diagonal interpolation, second horizontal interpolation and vertical interpolation. This algorithm has been compared with the nearest interpolation, bilinear interpolation, spline interpolation. Simulation results show this algorithm is with less computation complexity and can reduce the influences from noise.