How to remove shadow from frames extracted with foreground detector?

Im working on tracking the human silhouette with input from webcam. I have used vision.foregroundDetector to get the foreground masks. But they detect the shadows too. How to eliminate them? Code:

foregroundDetector = vision.ForegroundDetector('NumGaussians',3,'NumTrainingFrames',10,
'LearningRate',0.000001); 

vid = videoinput('winvideo', 1); %select input device 
i=1;
while(1) 
    %frame = step(vid); % read the next video frame
    frame = getsnapshot(vid);  
    foreground = step(foregroundDetector, frame);
    se = strel('square', 3);
    filteredForeground = imopen(foreground, se);
    fname = sprintf('frames/frame%d.jpg',i);
    imwrite(filteredForeground,fname,'jpg');
    i = i+1;
end

Output Frame:

Answer 1

[Dima Lisin]

One thing to try is to convert the video frame to a color space like HSV or YCbCr, and then only feed the chroma channels into the foreground detector. This is going to eliminate most shadows. However, it may also eliminate legitimate objects which do not have a lot of saturated colors.

[Avinash S]

Thanks for the idea Dima Lisin. I will try it