2019 Unicorn Enterprise Heavy Gold Recruitment Python Engineer Standard >>> 
Bicubic interpolation (also called coordination plate element), the binary bicubic interpolation formula has a total of (3+1)2=16 coefficients, and its general form can be written as:
a00 + a10x + a01y + a20x2 + a11xy + a02y2 + a21x2y + a12xy2 + a22x2y2 + a30x3 + a03y3 + a31x3y + a13xy3 + a32x3y2 + a23x2y3 + a33x3y3
Or a simpler form:
The bicubic interpolation method overcomes the shortcomings of bilinear interpolation and nearest neighbor interpolation algorithms. The calculation accuracy is relatively high, and the interpolation effect is better than the nearest neighbor interpolation method and the bilinear interpolation method, but the calculation amount is large. In the image domain, the method considers 16 neighbors around a floating point coordinate (i+u, j+v), and the target pixel value f(i+u, j+v) can be obtained by the following interpolation formula:
f(i+u,j+v)=[A]×[B]×[C]
[A]=[S(u+1) S(u+0) S(u-1) S(u-2)]
