image reconstruction using shepp-logan phantom

生成shepp-logan 三维头模型，从官网下载-Generate Shepp-Logan 3D head model, download the official website

This example shows how to scan an image with a limited angle, obtain the sinogram, add noise to make things worse, and reconstruct the initial image with great accuracy %You may want to remove/edit some sections if you intend to apply this to your u