Binary Graphcuts Pseudocode

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int m_lambda = 200; // change this value to change the weight of the smoothness or prior term

SOURCE_COLOR = cvScalar( 0, 0, 255 ); // blue = foreground
SINK_COLOR = cvScalar( 245, 210, 110 ); // yellow = background

for( int y = 0; y < img->height-1; y++ ) {
    for( int x = 0; x < img->width-1; x++ ){

    CvScalar c = cvGet2D( img, y, x );
    node = y * img->width + x;

    // data term:
    graph->add_tweights(node,dist(SOURCE_COLOR,c),dist(SINK_COLOR,c));

    // prior term: start

    int nx = x + 1; // the right neighbor
    int next_node = y*img->width+nx;
    graph->add_edge(node, next_node, m_lambda, m_lambda );

    int ny = y + 1; // the below neighbor
    next_node = ny*img->width+x;
    graph->add_edge(node, next_node, m_lambda, m_lambda );

    // prior term: end

    }
}

graph->maxflow();

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Here is the distance function:

int dist( CvScalar c1, CvScalar c2 )
{
    return ( abs( c1.val[0] - c2.val[0] )+
abs( c1.val[1] - c2.val[1] )+
abs( c1.val[2] - c2.val[2] )) / 3;
}