How do I make atrifacts for a synthetic image?

Hello to everyone, could anybody help me making artifacts for a synthetic image?

[Sean de Wolski]

ring artifact? beam artifact? archaeological artifact?

Answer 1

[Image Analyst]

Try this link: http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Jan]

This is an adequate answer. Neither "artifact" nor "synthetic image" is well defined, such that an answer can be pure guessing only. Please, Mary, explain all needed details.

Answer 2

[Sean de Wolski]

Ring artifacts and reconstruction artifacts for a parallel beam configuration:

I = imread('cameraman.tif');
theta = 0:.1:180; %make a bigger increment to add more reconstruction noise (e.g. 0:5:180);
S = radon(I,theta);
n = 5; %num rings
r = floor(rand(n,1)*size(S,1));
r2 = min(r+floor(rand(n,1)*8),size(S,1)); %max ring thickness is 8

for ii = 1:n
  S(r(ii):r2(ii),:) = bsxfun(@minus,S(r(ii):r2(ii),:),.4*range(S(r(ii):r2(ii),:),2));
end

I2 = uint8(iradon(S,theta));

imshow(I2)