Coherent Backscattering from Multiple Scattering Systems - KOPS ...

MATLAB codes
position = regions(index).Centroid ;
position = round (position) ;
% position = center of mass of blob area;
% position(1) = x, position(2) = y !!!
%% Calculate profile or average
mode_selector = ’average’ ;
% alternative: ’profile’
if strcmp(mode_selector, ’average’)
range = 1 ; % change value to average over a larger radial range
[intensity,error,pixels] = ...
calculate_average (matrix, errormatrix, position, range) ;
else
direction = 0 ; % change value to select other direction
range = 1 ; % change value to average over a larger radial range
[intensity,error,pixels] = ...
calculate_profile (matrix, errormatrix, position, direction, range) ;
end
%% Display result
plot ( pixels, intensity )
hold on
plot ( pixels, intensity-error, ’:’ )
plot ( pixels, intensity+error, ’:’ )
hold off
xlabel (’scattering angle [pixels]’)
ylabel (’intensity [a.u.]’)
end
function [intensity,error,pixels] = ...
calculate_average (matrix, errormatrix, position, range)
% create carthesian coordinate system
X = repmat(1:2048,2048,1) ;
Y = X’ ;
% shift origin of the coordinate system to ’position’
X = X - position(1) ;
Y = Y - position(2) ;
% turn carthesian coordinate system into polar coordinates
[theta,rho] = cart2pol (X,Y) ; % range of theta: [-pi,pi]
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