Crate shepplogan
source ·Expand description
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)