# Shepp-Logan Phantom in 2D

For reference see incontrastsRef.html.

    function q = shepp2D(X1,X2,varargin)
    % Shepp-Logan Phantom

    %P = phantom('Modified Shepp-Logan',200);
    %imshow(P)

    % seti = varargin{end};
    % R = seti.rCD/2;

    n = sqrt(length(X1));

    % -- image (square)

    %p = phantom('Modified Shepp-Logan',n); % p is n x n (this is not sparse enough)
    p = phantom('Modified Shepp-Logan',floor(n/2)); % p is n/2 x n/2

    % build mask
    x1 = 1:n;
    indx = (floor(n/2)-n/4<x1)&(x1<=floor(n/2)+n/4);
    mask = zeros(n,n);
    mask(indx,indx) = 1;

    % use mask
    y = zeros(size(mask));
    y(mask~=0) = p; % phantom

    % -- image end

    q = reshape(y,[1 n^2]);

    q = double(q);

    end