Fast discrete bilinear interpolation algorithm

Bilinear interpolation is widely used to process digital image.Its continuity is better than Nearest neighbor interpolation,but is time-consuming.In order to speed up,a discrete bilinear interpolation algorithm is proposed.First,pixel is cut into 3x3 sub-pixel.Then the center value of each sub-pixel with bilinear interpolation function is calculated,we can get a convolution function C related with each sub-pixel,the function C can be a substitute of bilinear interpolation.Theoretical analyses show that the discrete algorithm decreases the times of floating addition and floating multiplication.Experiments of image rotation show that the discrete algorithm improve the per-formance more greatly than that of bilinear interpolation.The quality of image rotated by the discrete algorithm is almost equal to that by the bilinear interpolation except for a little loss of continuity.