title: Reconstructing 3D image from 2D image algorithm
body: <p>I have some CT images for some rock, and I want to build a 3D image out of these images. This is the first time I work on image processing, and constructing 3D image out of CT 2D images sounds complicated for me. I've searched a lot, after searching I've ended up with these thoughts, </p>
  
  <ol>
  <li><p>To construct a 3D image from 2D one you need to find depth map which indicates how far or near an object is to the camera. Then this map will help constructing the 3D image (I don't know how, and I didn't find a clear resource about that). </p></li>
  <li><p>There exist multiple algorithms for such a reconstruction, like analytical, iterative, and statistical. After searching it seems to me that the last two types are better than the first one. </p></li>
  </ol>
  
  <p>I've read too many resources like research papers and survey papers, but they were very technical and I couldn't connect the information mentioned within them. </p>
  
  <p>Here are few results of my searching process, </p>
  
  <p><a href="https://stackoverflow.com/questions/4436507/getting-3D-image-from-2d-image">Getting 3D image from 2D image</a></p>
  
  <p><a href="https://www.aapm.org/meetings/02AM/pdf/8372-23331.pdf" rel="nofollow noreferrer">https://www.aapm.org/meetings/02AM/pdf/8372-23331.pdf</a></p>
  
  <p><a href="https://en.wikipedia.org/wiki/Iterative_reconstruction" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Iterative_reconstruction</a></p>
  
  <p>None of the above resources explains the process in a simple way. </p>
  
  <p>I know that there are some software that can do this job, but before using any, I want to understand the algorithm mathematically itself. </p>
  
  <p>Can anyone please explain in steps how the algorithm of 3D image reconstruction from 2D CT images work, specially for the iterative and statistical methods? </p>