双线性插值是指利用映射点在输入图像的4 个邻点的灰度值对映射点进行插值,即待插点处的数值用离待插点最近的四个点的值加权求得。在同一行内根据待插值像素点与其前后的原图像像素点的位置距离进行加权线性插值,即离原图像像素点越近的待插值像素点,原图像像素的加权系数就越大 行间根据待插值行与其上下的原图像行间的距离进行加权线性插值,即离原图像行越近的待插值行,原图像行的加权系数就越大-Bilinear mapping point is the use of four adjacent points in the input image gray value interpolation to map points, namely at the point to be interpolated values to be interpolated　point values using weighted to obtain the most recent four points. In the same row based on the location of the original image pixel to be interpolated pixel and its front and rear of the distance-weighted linear interpolation, that is　the original image pixels near the pixel to be interpolated, the weighting coefficients of the original image pixel is greater　between the lines according to distance to be interpolated image lines up and down the line to its original weighting between the linear interpolation, that is farther away　the original image near the line to be interpolated, the weighting coefficients of the original image lines, the greater the