How can I improve my MATLAB program for the Biot Savart Law?

[arronslacey]

Hi, if anyone good with MATLAB and knows biot savart law then i hope you can help. I have the following program:

 clear all
 Img = imread('littlecircle.png');
 Img = Img(:,:,1);
 Img = double(Img);
 w = size(Img,1);               % width size
 h = size(Img,2);               % height size
 [Ix,Iy] = gradient(Img);       %gradient of image
 
 i=1;     %iteration for magnetic field loop
 b=0;     %initialize b to zero
 
 % Magnetic Field
 for pxRow = 1:h % fixed pixel row
 for pxCol = 1:w % fixed pixel column
 
 for r = 1:h % row of distant pixel
 for c = 1:w % column of distant pixel
 
 R(c,r) = sqrt((r-pxRow)^2 + (c-pxCol)^2);                               % pythagoras theorem to get distance to each pixel
 O(c,r) = atan(Iy(c,r)./Ix(c,r));                         % direction of current
 If(c,r) = sqrt((Ix(c,r)).^2 + (Iy(c,r)).^2);                            % magnitude of current 
 Rxs(c,r) = R(c,r)./norm(R(c,r));                                        % unit vector from x to s                     
 b(c,r) = If(c,r).*O(c,r).*(Rxs(c,r)./(R(c,r)).^2);                      % b field = If(s)O(s) x Rxs/R.^2  BIOT SAVART LAWRxs/R.^2  BIOT SAVART LAW
 end
 end
 B(i) = {b}; % filling a cell array with results. read below
 i = i+1;
 end
 end

all lines in red are currently not calculating what I want them to. Can anyone help? Thanks!

 

[arronslacey]

by the way, here is the reference paper http://www.cs.swan.ac.uk/~csjason/papers/xxmm-pami2008.pdf