formula of gaussian curvature filter?

[Rongnian]

Dear Dr. Yuanhao Gong,
Thanks for your code. But I have a question about the GC filter. In your thesis, Algorithm 11 (also Algorithm 1 in the TIP paper) defines the projection distance of Pg as:
d5=U(i-1,j) + U(i,j-1) - U(i-1,j-1) - U(i,j)
However, in your code it becomes
d5=[U(i-1,j) + U(i,j-1) + U(i-1,j-1)]/3 - U(i,j)
I think these two formulas are different, but which one is correct?