Patent ID: 7671872

Claim:
A chrominance space region determination method performed by a chrominance space region determination apparatus for determining which one of regions in a chrominance space an input point belongs to, the chrominance space having, a Cb axis, a Cr axis, and an origin which is an intersection of the Cb axis and Cr axis, and the regions being defined by boundary lines each of which extend from the origin on a Cr-Cb area including the Cb axis and Cr axis, the method comprising: computing, with a coordinate calculation unit of the chrominance space region determination apparatus, a coordinate of a first intersection point in the chrominance space at which a first line extending through the input point and the origin intersects with a second line connecting a point on the Cb axis and a point on the Cr axis; comparing, with a determination device of the chrominance space region determination apparatus, a coordinate of a first intersection point at which the first line and the second line intersect, and coordinates of second intersection points at which the second line and the boundary lines intersect, to determine the region to which the input point belongs.