[computer-go] Voronoi diagram revisited

[Hideki Kato]

Hello, I'm gg aka Hideki Kato.

I got back to Voronoi diagram for computer-go and found that it's useful for 
denoting critical points ("kyusho" in Japanese).

In the "geta" pattern below, to-be-captured white stone's three free points 
(including diagonals, i.e., "kosumi") are categorized into two classes. 
One is with the same color (white) and the other is with neutoral color, in the
Voronoi diagram. Former is the critical point in this pattern (@). That is, I 
guess Voronoi diagram can be used to find important points (not only 
liberties).

++++++
+X+ at ++
OXO+++
OOXX++
+OO+++

Corresponding Voronoi diagram with Manhattan distance is (+ is neutral point):

XXX+O+
+X+O+X
OXO+XX
OOXXXX
OOO+XX

The upper right point of the white stone in question has the 
same color in Voronoi diagram and is the critical point of this pattern.

I believe this can be used for detecting important points in some cases, 
hopefully an alternative for local shape pattern matchers, though not verified 
yet.

Sorry for short report but I think it's better to share this discovery with 
this ml asap.

-gg
--
gg (Kato)