双三次插值(Bicubic interpolation) Point to estimate (i'j) g(x.y)= fyW(Dw() W(x) (a+2)lx3-(a+3)lx2+1xl≤1 Final image alx13-51x12+8alxl 4a 1<x<2 0 otherwise BiCubic函数具有如下形状： Extoct tronsformed position of (1) Original image 2.0 1.0 0.0 10h2.0 1.R.Keys(1981)."Cubic convolution interpolation for digital image processing".IEEE Transactions on Acoustics,Speech,and Signal Processing.29 (6):1153-1160 doi:10.1109/TASSP.1981.11637112