error using blobAnalysis/step

filename = '../dataset/video.avi';

hsrc = vision.VideoFileReader(filename,'ImageColorSpace','RGB','VideoOutputDataType','uint8');

% ------------------------------------------------------------------------------------------

blobAnalysis = vision.BlobAnalysis('BoundingBoxOutputPort', true, ...

'AreaOutputPort', true, 'CentroidOutputPort', true, ...

'MinimumBlobArea', 50);

se = strel('square',3);

% -------------------------------------------------------------------------------------------

% Create background/foreground segmentation object

hfg = backgroundSubtractor(algorithm);

disp('Starting...');

frameCnt = 1;

while ~isDone(hsrc), %disp(frameCnt)

% Read frame

frame = step(hsrc);

% Compute foreground mask and background model

[fgMask, bgModel] = getForegroundMask(hfg, frame);

%--------------------------------------------------------------------------

filteredForeground = imopen(fgMask, se);

bbox = step(blobAnalysis, filteredForeground);

result = insertShape(hsrc, 'Rectangle', bbox, 'Color', 'green');

numCars = size(bbox, 1);

result = insertText(result, [10 10], numCars, 'BoxOpacity', 1, ...

% 'FontSize', 14);

%--------------------------------------------------------------------------

% View results

subplot(2,3,1), imshow(frame,'InitialMagnification','fit');

subplot(2,3,2), imshow(filteredForeground,'InitialMagnification','fit');

subplot(2,3,3), imshow(bgModel,'InitialMagnification','fit');

subplot(2,3,4), imshow(fgMask,'InitialMagnification','fit');

pause(0.01);

% Reset background model

% This step just demonstrates how to use reset method

if (frameCnt==5)

%reset(hfg);

%break;

end

frameCnt = frameCnt + 1;

end

disp('Finished!');

release(hfg);

release(hsrc);