Removing gaps between the boundary or filling inside the boundary

Can anyone help in how to join the discontinuous boundary of this image. And how to fill inside this boundary. the image is obtained using 'Sobel edge detector in Matlab'.

Answer 1

[Image Analyst]

Sobel is probably not good, or not enough. If it's a video of a person walking, try optical flow. Why do you think edge detection is the best approach?

[BlueBee77]

I tried the other edge detectors but they are giving some extra details. Sobel is good because it gives less detail and i am interested only in the boundary. Dilation and erosion gives exactly what i need (filling inside the boundary). But the problem comes when there is a long gap in the boundary. I need a perfect human silhouette, does optical flow can help me in getting a perfect boundary? And what you think about Viola jones?