# [−][src]Crate shepplogan

# Shepp-Logan phantom

Have you ever had the need to create hundreds to thousands of Shepp-Logan phantoms per second?
Well if you do, you're doing something wrong, but you've come to the right place.
The Shepp-Logan phantom is a numerical phantom which is defined as the sum of 10 ellipses. It
is often used as a test image for image reconstruction algorithms.
This crate provides a dependency-free, efficient implementation for creating Shepp-Logan
phantoms in 2D.
The following results were obtained with `cargo bench`

on an Intel Core i7 with 2.70GHz:

Resolution | time | fps |
---|---|---|

128x128 | 111,000ns | 9000 |

256x256 | 440,000ns | 2200 |

512x512 | 1,780,000ns | 560 |

Two versions are provided: The original version as described in [0] and a modified version, which has higher contrast as described in [1]. If you do not know the difference between those two, you most likely want the modified version.

To use the crate, add `shepplogan`

to your `Cargo.toml`

:

```
shepplogan = "^1"
```

# Example

extern crate shepplogan; use shepplogan::{shepplogan, shepplogan_modified}; // Dimensions of the image grid let (nx, ny) = (256, 320); // Original Shepp-Logan Phantom (the dynamic range is between 0.0 and 2.0) let phantom = shepplogan(nx, ny); // Modified Shepp-Logan Phantom (the dynamic range is between 0.0 and 1.0) let phantom_modified = shepplogan_modified(nx, ny);

See `examples/example.rs`

for an example which saves the phantom to disk.

You can also create your own phantom by defining ellipses:

extern crate shepplogan; use shepplogan::{phantom, Ellipse}; // Dimensions of the image grid let (nx, ny) = (256, 320); // Define two ellipses let ellipses = [ Ellipse::new(0.0, -0.0184, 0.6624, 0.874, 0.0, -0.98), Ellipse::new(0.0, 0.0, 0.69, 0.92, 0.0, 2.0), ]; let ph = phantom(&ellipses, nx, ny);

This will create a phantom consisting of two ellipses.

# References

[0] Shepp, LA and Logan BF, "The Fourier reconstruction of a head section." IEEE Transactions on Nuclear Science 21, No. 3 (1974)

[1] Toft, PA, "The Radon Transform - Theory and Implementation", PhD dissertation, Departement of Mathematical Modelling, Technical University of Denmark (1996)

## Structs

Ellipse | Ellipse |

## Functions

phantom | Creates a phantom based on given ellipses |

shepplogan | Original Shepp-Logan phantom |

shepplogan_modified | Modified Shepp-Logan phantom with better contrast |