Fig. 8

Schematic diagram of the boundary extraction method. B(i, j) is the current pixel, and \(B(i, j +1)\), \(B(i, j -1)\), \(B(i +1, j)\), \(B(i -1, j)\) represent four adjacent pixels
Schematic diagram of the boundary extraction method. B(i, j) is the current pixel, and \(B(i, j +1)\), \(B(i, j -1)\), \(B(i +1, j)\), \(B(i -1, j)\) represent four adjacent pixels