hw3

代码说明：

  Download the file town .jpg, which is a 1024×768, 256-grayscale image taken on a bright sunny day. The image was taken in the shadow of a building. As the result, the sunlight areas are glaring white and the shadow areas are dark and low contrast. Using the image enhancement techniques covered in class, increase the contrast and the brightness of the dark areas, and reduce the brightness of the sunny areas