Method and apparatus for qualifying an object comprising the steps of determining several characteristic values of the object, arranging the characteristic values in a sequence in a polar coordinate system having an origin, determining at least one quality point as centre of gravity on the basis of positions of the characteristic values in the polar coordinate system and qualifying the object according to position of said at least one quality point in the polar coordinate system, wherein in determining the at least one quality point the characteristic values are taken into account by weighting with their distances from the origin of the polar coordinate system.
