1. An image processing method of extracting geometrical data of the spine, for extracting the left and right pedicle landmarks of each spine vertebra, comprising steps of: acquiring image data of a 2-D frontal image of the spine; associating spine States to vertebra positions along the spine and estimating locations of left and right pedicle landmark Candidates (P L and P R ) in each State (V); defining a State Cost for forming Couples of left and right pedicle landmark Candidates; estimating sets of Best Couple Candidates, in each State, from the lowest State Costs; defining a Path Cost to go from one State to the next State; selecting a pedicle landmark Couple in each spine State among the Best Couple Candidates from the minimum Path Costs, and localizing the left and right pedicle landmarks of each spine vertebra from said selected pedicle landmark Couple.