中文说明：这是一个理想的迭代模型代码，采用MATLAB编写，方便学习，中间有投影和反投影过程，迭代次数可自行设置，图像大小为128方阵的头针模型
English Description：
This is an ideal iterative model code, using MATLAB to write, easy to learn, the middle of the projection and back projection process, the number of iterations can be set, the image size of 128 square matrix of the scalp model