 雙線性內插法(bi-linear interpolation) 此方法以(x,y)的四個鄰近點來求得最近似的灰度 -err

Deleted interpolation 算法， 综合了trigram, bigram, unigram 模型的一总简单的线性插值-deleted interpolation algorithm, mixed trigram, bigram, unigram model, and using simple linear interpolation