Reconstructing an Image from Fan-Beam Projection Data :: Transforms (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Reconstructing an Image from Fan-Beam Projection Data

To reconstruct an image from fan-beam projection data, use the ifanbeam function. With this function, you specify as arguments the projection data and the distance between the vertex of the fan-beam projections and the center of rotation when the projection data was created. For example, this code recreates the image I from the projection data P and distance D.

```
I = ifanbeam(P,D);
```

By default, the ifanbeam function assumes that the fan-beam projection data was created using the arc fan sensor geometry, with beams spaced at 1 degree angles and projections taken at 1 degree increments over a full 360 degree range. As with the fanbeam function, you can use ifanbeam parameters to specify other values for these characteristics of the projection data. Use the same values for these parameters that were used when the projection data was created. For more information about these parameters, see Computing Fan-Beam Projection Data.

The ifanbeam function converts the fan-beam projection data to parallel-beam projection data with the fan2para function, and then calls the iradon function to perform the image reconstruction. For this reason, the ifanfeam function supports certain iradon parameters, which it passes to the iradon function. See Inverse Radon Transform for more information about the iradon function.

Computing Fan-Beam Projection Data Working with Fan-Beam Projection Data