need some help with this matlab code...

clc
clear all
v = VideoReader('test.avi');
video1 = read(v,[10 inf]);
video1 = mat2cell(video1, size(video1,1), size(video1,2), size(video1,3), ones(1,size(video1,4)) );
disp('Extracting Foreground..');
fg = extractForeground(video1,30,4,0);
disp('Eliminating Noise from Foreground..');
fg_smooth=detectBlob(fg);
disp('Evaluating Motion History Image of the video..');
motion_history = MHI(fg_smooth);
disp('Determining Ellipse Statistical Properties..');
c = centroid(fg_smooth);
centroids = centroid(fg);
[thetas rhos] = OrientEccent(fg_smooth, c);
fg_drawn = DrawEllipse(fg,centroids,thetas,rhos)
figure(1);
imshow(fg{22})
title('Foreground Extraction');
figure(2);
imshow(fg_smooth{22})
title('Noise Elimination');
figure(3);
imshow(fg_drawn{22})
title('Ellipse Detection');

T=15;
frameDisp = motion_history{22};
frameDisp = double(frameDisp);
frameDisp = frameDisp ./ T;
figure(4);
imshow(frameDisp)
title('MHI Image');
disp('Analyzing Statistics for Video..');
[sigma_t sigma_r c_motion] = statistics(thetas, rhos, motion_history);
figure(5)
subplot(2,2,1);
plot(sigma_t);
title('Theta Std Dev Values');
subplot(2,2,2);
plot(sigma_r);
title('Rho Std Dev Values');
subplot(2,2,3);
plot(c_motion);
title('C Motion Values');

maxTheta = max(sigma_t);
gaussianFilter = fspecial('gaussian', [9, 9], 3.8);

for t = 1:(length(sigma_t)-5)
    if(c_motion(t) > 0.65 && sigma_t(t) >= 0.9*maxTheta)
        disp('FALL DETECTED!!');
        figure(6);
        imshow(imfilter(video1{t+5}, gaussianFilter));
        break;
    end
end
disp('Done');

function drawEllipse

function fg_drawn = DrawEllipse(fg,centroids,thetas,rhos)

fg_drawn = fg;

NumOfFrames = length(fg);

t = 0:.01:2*pi;

for frameIndex = 1:NumOfFrames

      theta = thetas(frameIndex);

      %TO BE MODIFIED
      b = 60;
      a = b / rhos(frameIndex);

      h = centroids(frameIndex,1);
      k = centroids(frameIndex,2);

      x = h + cos(theta)*(a*cos(t)) - sin(theta)*(b*sin(t));
      y = k + sin(theta)*(a*cos(t)) + cos(theta)*(b*sin(t));

      for c = 1:length(x)
          fg_drawn{frameIndex}( round(y(c)) , round(x(c)) ) = 0.5;
      end

      fg_drawn{frameIndex}( round(centroids(frameIndex,2)) , round(centroids(frameIndex,1)) ) = .5;

end

when i run the m file the error i get is

Error in DrawEllipse (line 33)
        fg_drawn{frameIndex}( round(y(c)) , round(x(c)) ) = 0.5;

Error in FallDetect (line 50)
fg_drawn = DrawEllipse(fg,centroids,thetas,rhos)

Can someone help me to fix this code please?

[Stephen23]

Please give us the complete error message, not just the bits that you think are interesting. The complete error message is all of the red text.

[Rash Anan]

ohh sorry didn't see the first line.

Attempted to access fg_drawn.%cell(89,0); index must be a positive integer or logical.

Error in DrawEllipse (line 33)
        fg_drawn{frameIndex}( round(y(c)) , round(x(c)) ) = 0.5;

Error in FallDetect (line 50)
fg_drawn = DrawEllipse(fg,centroids,thetas,rhos)

Answer 1

[Walter Roberson]

There is nothing in your code that prevents x or y from going negative. Remember, theta and rhos are estimates, and ellipses might be detected near borders.

[Rash Anan]

so what i can do is change this line in

fg_drawn{frameIndex}( round(y(c)) , round(x(c)) ) = 0.5;
to something which gives a positive number?
or is there any other way to make this code workable?

Answer 2

[Image Analyst]

You can't have fractional indexes. See the FAQ: http://matlab.wikia.com/wiki/FAQ#How_do_I_fix_the_error_.22Subscript_indices_must_either_be_real_positive_integers_or_logicals..22.3F

Your x and y, even though you round them, could be zero or negative and all indexes must be natural integers 1,2,3,4,5,......

[Rash Anan]

so what i can do is change this line 

fg_drawn{frameIndex}( round(y(c)) , round(x(c)) ) = 0.5;
into something like this

fg_drawn{frameIndex}( 1+round(y(c)) , 1+round(x(c)) ) = 0.5;

or is there any other way to make this code workable?

[Image Analyst]

If that makes the indexes start at 1, and it gives you everything else that you want, then yeah, I guess you're good to go.