中文说明：最简洁最好用的一份sift代码，注释什么的都比较适合初学者，简明易懂，不需再做其他编译，例子图是经典的例图
English Description：
Most simple is best to use a sift of code, comments, or something more suitable for beginners, easy to understand and do not need to make other compilation, for example, is a classic illustration