在离散数据的基础上补插连续函数，使得这条连续曲线通过全部给定的离散数据点。插值是离散函数逼近的重要方法，利用它可通过函数在有限个点处的取值状况，估算出函数在其他点处的近似值。插值：用来填充图像变换时像素之间的空隙。(On the basis of discrete data, a continuous function is inserted to make the continuous curve pass through all the given discrete data points. Interpolation is an important method of approximation of discrete functions. It can be used to estimate the approximate values of functions at other points by means of the values of the functions at finite points. Interpolation: used to fill the space between pixels when an image is transformed.)