Brige Detection By Road Detection

Roadlikeness

    for each point x, y in grid:
       R = compute "roads" through (x, y) of length L
       r = the flattest road in R /* minimize flatness */
       mf = flatness_m(r) /* \max_{i=0}^{n-1} |height(i)-height(i+1)| */
       sf = flatness_s(r) /* \sum_{i=0}^{n-1} |height(i)-height(i+1)| */
       vf = variation_s(r) /* stddev of abs height diffs */ 
       pf = flatness_m(perpendicular(r))

       rlikeness(x,y) = A/(a+mf) + B/(b+sf) + C/(c+vf) + D*pf