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stefan-k/shepplogan-rs

shepplogan-rs

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shepplogan-rs

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"

The documentation can be found here.

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)

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

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