将一幅512×512的原始灰度图像，采用3×3的平均窗口对它作滤波运算（原图像外围的像素的灰度值视为128）；对滤波后图像隔行、隔列丢弃一半像素形成一幅256×256的小图像；对此小图像分别采用最邻近内插、双线性内插的方法将它放大为512×512的大图像。对照原图像，计算两种放大图像各自的PSNR。-A grayscale original image of 512 × 512, using a 3 × 3 window average (gradation values ​ ​ of pixels of the original image 128 is assumed as a peripheral) as its filter operation　interlaced image after filtering, every row of pixels to discard half 256 × 256 forming a small image　this small image within the respectively adjacent interpolation, bilinear interpolation method to enlarge it to a large image of 512 × 512. Comparison of the original image, calculating two kinds of enlarged image of each PSNR.