freground detection by GMM in matlab

Hi every body. I obtain foreground objects from my video, but the foreground detected have extra parts like this:

How I can create a foreground without this point or how I can remove them? my code is:

    D = dir([FilePath, '\*.jpg']);
    Num = length(D(not([D.isdir])));
    detector = vision.ForegroundDetector(...
    'NumTrainingFrames', 20,'LearningRate',0.005,'MinimumBackgroundRatio',0.5,...
    'InitialVariance', ((30)*(30)));
    array=struct2cell(D(not([D.isdir])));
    array_names=array(1,:);
    for i=1:Num
        CurrentImage = imread(strcat(FilePath,'\',array_names{i}));
        fgMask = step(detector, CurrentImage);
        imwrite(fgMask,strcat(OutputFile,'\',int2str(i),'.png'),'png');
    end

Answer 1

[Dima Lisin]

In general, you can use morphological operations, such as imopen to remove noise, and imclose to fill in small gaps.

In this particular case, the extra part seems to be caused by a shadow. You can try converting your frames to YCbCr color space using rgb2ycbcr, and only use the Cb and Cr channels for the foreground detector. This will get rid of shadows, but it will also remove any objects that are grey.