An improved Canny operator used for aero-engine's blade welding and repairing

The Canny operator has been widely applied on the edge detection due to the good effect. In the process of repairing the civil aviation engine titanium alloy blade, discontinuous edges will appear because of the influence of complex fixtures and high reflective characteristics of blade. Therefore, bases on the non-maximum part suppression, an improved Canny operator method is proposed. Firstly, this method makes the maximum gradient value points as candidate the edge. And then, for reducing the influence of environmental factors, the non-maximum points are screened with keeping non-adjacent the maximum points as the edge map in the 8 neighborhood. Finally, the Otsu algorithm is used for threshold selection to increased adaptability. Experimental results show that the connecting points are improved in proportion of the total number of edge points from 0.686 to 0.904. Without increase in time, the detected edge is enhanced in terms of continuity and edge detection effect is good.