An advanced orthoimage mosaicking method for urban areas based on edge thickening

This work is an improved version of the previous work. In order to solve the problem that the seamlines are too close to the edges of buildings, a thickened edge diagram are firstly generated and then used for searching seamlines with A* algorithm. The height gradient term is replaced by the root mean square value of height gradients term to generate thickened edge diagram. The thickened edges also bring some troubles that the edges of the adjacent buildings may be connected to each other. It will block the searching algorithm from finding a path through the two buildings. To tackle this problem, the height term is added to the cost function. By doing this, the searching algorithm will find a path across the area between two adjacent buildings since the area between the buildings have small height than on the building. We also defined constrained areas for searching the seamlines. The constrained areas make sure that the seamlines will not intersect to each other. Preliminary results show that the proposed method produces better results than the previous work by both visual and quantitative comparison.