22. The data process unit according to claim 21 , wherein the region dividing means divides the low dimensional vectors corresponding to pattern models more finely with increasing radial distance from the innermost circle.
21. The data process unit according to any of claims 18 to 20 , wherein the region dividing means divides the plurality of low dimensional vectors corresponding to pattern models by an outer circle and n inner circles (n is an integer equal to or larger than 1) and further divides ring-shaped regions formed by the concentric outer and inner circles therebetween into a plurality of regions by lines extending radially, where the outer circle is centered at the center of gravity of the coordinate points of all the low dimensional vectors corresponding to pattern models and has a radius equal to the distance between the center of gravity and the coordinate point of the low dimensional vector corresponding to pattern model farthest from the center of gravity while the inner circle is centered at the center of gravity and has a radius smaller than that of the outer circle.