void HandDescriptor::handPalmExtraction ( ) [private]
Finds the maximum inscribed circle of the hand contour, which describes the hand palm.
{
    //-- Parameters describing this hand palm procedure:
    const int x_ratio = 3; //-- Section of the bounding box used for finding center (along X)
    const int y_ratio = 3; //-- Section of the bounding box used for finding center (along Y)

    const int step_contour = 1; //-- Test each 'step' points of the contour for easier calculations
    const int step_points_inside = 1;//-- Test each 'step' points inside the contour


    //-- Extract points to use
    std::vector< cv::Point > points_to_use;

    if ( step_contour == 1)
    {
        points_to_use = _hand_contour[0];
    }
    else
    {
        for (int i = 0; i < (int) ( _hand_contour[0].size() / (float) step_contour); i++)
            points_to_use.push_back( _hand_contour[0][i]);
    }

    //-- Find initial and ending points of the area to look for
    std::pair<int,int> x_limits, y_limits;

    x_limits.first = _hand_bounding_box.x + _hand_bounding_box.width /  x_ratio;
    x_limits.second = _hand_bounding_box.x + (int) ( _hand_bounding_box.width * (1 - 1 /(float) x_ratio));

    y_limits.first = _hand_bounding_box.y + _hand_bounding_box.height / y_ratio;
    y_limits.second = _hand_bounding_box.y + (int) ( _hand_bounding_box.height * (1 - 1 /(float) y_ratio));


    //-- Look for center and radius
    std::pair<int, int> best_center = std::pair<int, int>( x_limits.first, y_limits.first);
    double best_distance = -1;

    /*
    std::cout << "(" << x_limits.first << ", " << x_limits.second << ")" << std::endl;
    std::cout << "(" << y_limits.first << ", " << y_limits.second << ")" << std::endl;
    */

    for (int j = y_limits.first; j < y_limits.second; j += step_points_inside )
        for (int i = x_limits.first; i < x_limits.second; i += step_points_inside )
        {
            double current_distance = cv::pointPolygonTest( points_to_use, cv::Point(i, j), true );

            if (current_distance > 0 && current_distance > best_distance)
            {
                best_distance = current_distance;
                best_center.first = i;
                best_center.second = j;
            }
        }


    //-- Once best distance is found, we get the center and calculate the actual radius (only if something is found)
    if ( best_distance > -1 )
    {
        _max_circle_incribed_center = cv::Point( best_center.first, best_center.second );
        _max_circle_inscribed_radius = best_distance;
       // std::cout << "[Debug] Inscribed circle: " << _max_circle_incribed_center << " -> r =" << _max_circle_inscribed_radius << std::endl;
    }
    else
    {
        std::cerr << "[Error]: Inscribed circle could not be found!" << std::endl;
    }

}