数字图像处理：（1）输入图像，采用半色调技术并将图像打印和显示。（2）按要求降低图像的灰度级。（3）采用像素复制的方法对图像进行缩放。（4）采用双线性插值法的方法对图像进行缩放。-Image Printing Program Based on Halftoning　 The following figure shows ten shades of gray approximated by dot patterns.　Each gray level is represented by a 3 x 3 pattern of black and white dots.　A 3 x 3 area full of black dots is the approximation to gray-level black, or 0.　Similarly, a 3 x 3 area of white dots represents gray level 9, or white.　The other dot patterns are approximations to gray levels in between these two extremes.　A gray-level printing scheme based on dots patterns such as these is called　halftoning.　 Note that each pixel in an input image will correspond to 3 x 3 pixels on the printed image, so spatial resolution will be reduced to 33　of the original in both the vertical and horizontal direction.　Size scaling as required in (a) may further reduce resolution, depending on the size of the input image. (a) Write a halftoning computer program for printing gray-scale images based on the dot patterns just discussed.　Your program must be able to scale the size of