Function Siemens_star () % Matlab source code for creating your own star % Siemens Star % Hans Strasburger, June 2018 number_of_spikes = 128 % fill in as you wish radius = 40 % Siemens star radius axis equal % 1:1 aspect ratio axis off % but no frame hold on % fill graph one by one % Define points along the circumference theta = - pi : 2 * pi / number_of_spikes : pi % theta is a vector of angles x = radius * cos ( theta ) % a vector of points along the outer circumference y = radius * sin ( theta ) % ' % Draw triangular spikes leave every 2nd spike white for k = 1 : ( number_of_spikes / 2 ) % k goes from 1 to the number of endpoints along the circle % A spike has 4 vertices, the first and last one in the center, so the vectors X, Y, have length 4 X = Y = C = 'black' p = patch ( X, Y, C, 'EdgeColor', 'none' ) % draws the spike (with no edge), using the 'patch' function end % end of for loop % Save the resulting Siemens star in vector graphics format to work properly (svg, eps, etc. Prt Tourner designed this Mega Star Back focus Test Chart to be in a handy size to allow operators to check the sharpness of their lens or camera in a.

Focus chart with a siemens star