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244 Chapter 6 ■ Thinning

im->data[r-1] [c+2] == 0 &&
im->data[r-2] [c-1] == 0 &&
im->data[r-2] [c] == 0 && im->data[r-2] [c+1] == 0
{
im->data[r] [c] = 2;
return;
}
/ * U5 * /
if (k>=5)
if (im->data[r+2] [c-2] == 0 && im->data[r+2] [c-1] == 0 &&
im->data[r+2] [c] == 1 && im->data[r+2] [c+1] == 1 &&
im->data[r+2] [c+2] == 0 &&
im+>data[r+1] [c-2] == 0 && im->data[r+1] [c-1] == 0 &&
im->data[r+1] [c] == 1 && im->data[r+1] [c+1] == 1 &&
im->data[r+1] [c+2] == 0 &&
im->data[r] [c-2] == 0 && im->data[r] [c-1] == 0 &&
im->data[r] [c] == 0 && im->data[r] [c+1] == 0 &&
im->data[r] [c+2] == 0 &&
im->data[r-1] [c-2] == 0 && im->data[r-1] [c-1] == 0 &&
im->data[r-1] [c] == 0 && im->data[r-1] [c+1] == 0 &&
im->data[r-1] [c+2] == 0 &&
im->data[r-2] [c-1] == 0 &&
im->data[r-2] [c] == 0 && im->data[r-2] [c+1] == 0)
}
{
im->data[r] [c] = 2;
return;
}
}
*
/ * Yokoi’s connectivity measure /
int Yokoi (IMAGE im, int r, int c)
{
int N[9];
int i, j, k, i1, i2;
N[0] = im->data[r] [c] != 0;
N[1] = im->data[r] [c+1] != 0;
N[2] = im->data[r-1] [c+1] != 0;
N[3] = im->data[r-1] [c] != 0;
N[4] = im->data[r-1] [c-1] != 0;
N[5] = im->data[r] [c-1] != 0;
N[6] = im->data[r+1] [c-1] != 0;
N[7] = im->data[r+1] [c] != 0;
N[8] = im->data[r+1] [c+1] != 0;
k= 0
for (i=1; i<=7; i+=2)
{
i1 = i+1; if (i1 > 8) i1 -= 8;
i2 = 1+2; if (i2 > 8) i2 -= 8;
k += (N[i] - N[i] * N[i1] * N[i2]);
}