A method includes: obtaining designated 3D template for a designated part in a heart generating 3D annulus data representing an annulus of a heart valve identified as a reference of transformation, from a cross-section image in a plane passing through an axis within the annulus of the identified heart valve in 3D volume data generated from tomographic images identifying a first point on the annulus of the identified heart valve in the designated 3D template and a second point on the annulus represented by the 3D annulus data arranging n starting points from the first point on the annulus of the identified heart valve in the designated 3D template and n target points from the second point on the annulus represented by the 3D annulus data and calculating movement destination coordinates of vertices of polygons relating to the designated 3D template to transform the designated 3D template.
