package edu.stanford.rsl.tutorial.parallel;
import edu.stanford.rsl.conrad.data.numeric.Grid2D;
import edu.stanford.rsl.tutorial.filters.RamLakKernel;
import edu.stanford.rsl.tutorial.phantoms.DotsGrid2D;
import edu.stanford.rsl.tutorial.phantoms.Phantom;
import ij.ImageJ;
/**
* This is a simple example of a parallel-beam reconstruction.
* First, a phantom is created. Then we generate parallel projections using a parallel projector.
* This allows us to visualize the sinogram.
* For reconstruction, we filter the sinogram for every detector row.
* Then, the sinogram is backprojected.
*
* @author Shiyang Hu
*
*/
public class ParallelReconExample {
public static void main (String [] args){
new ImageJ();
int x = 200;
int y = 200;
// Create a phantom
Phantom phan = new DotsGrid2D(x, y);
//phan = new UniformCircleGrid2D(x, y);
//phan = new MickeyMouseGrid2D(x, y);
phan.show("The Phantom");
// Project forward parallel
ParallelProjector2D projector = new ParallelProjector2D(Math.PI, Math.PI/180.0, 400, 1);
Grid2D sinogram = projector.projectRayDrivenCL(phan);
sinogram.show("The Sinogram");
Grid2D filteredSinogram = new Grid2D(sinogram);
// Filter with RamLak
RamLakKernel ramLak = new RamLakKernel(400, 1);
for (int theta = 0; theta < sinogram.getSize()[1]; ++theta) {
ramLak.applyToGrid(filteredSinogram.getSubGrid(theta));
}
filteredSinogram.show("The Filtered Sinogram");
// Backproject and show
ParallelBackprojector2D backproj = new ParallelBackprojector2D(200, 200, 1, 1);
backproj.backprojectPixelDriven(filteredSinogram).show("The Reconstruction");
}
}
/*
* Copyright (C) 2010-2014 Shiyang Hu
* CONRAD is developed as an Open Source project under the GNU General Public License (GPL).
*/