PROBLEM TO BE SOLVED: To delete an abnormal protrusion area from a three-dimensional image of a blood vessel.SOLUTION: A control device 102 specifies a center line of a blood vessel based on three-dimensional blood vessel data which expresses a three-dimensional shape of a blood vessel, then specifies a center line of a protrusion part of the blood vessel out of the center line, then specifies a center line which branches from the protrusion part center line. The control device 102 defines a cylindrical coordinate system in which, for three-dimensional data of a blood vessel corresponding to a branched center line, a peripheral direction of the blood vessel from the center line, a radial direction of the blood vessel from the center line, and the center line direction are coordinate axes, then converts blood vessel data expressed in the cylindrical coordinate system into blood vessel data of an orthogonal coordinate system. Then, by using a coordinate value of the coordinate axis in the radial direction on a first coordinate value of the coordinate axis in the center line direction and a coordinate value of the coordinate axis in the radial direction on a second coordinate value on the coordinate axis in the center line direction in the blood vessel data in the orthogonal coordinate system, the control device interpolates a coordinate value of the coordinate axis in the radial direction from the first coordinate value to the second coordinate value, then converts the blood vessel data in the orthogonal coordinate data after subjected to interpolation into blood vessel data in the cylindrical coordinate system.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2017,JPO&INPIT【課題】血管の３次元画像から異常突出領域を削除すること。【解決手段】制御装置１０２は、血管の３次元形状を表した３次元血管データに基づいて、血管の中心線を特定し、中心線の中から血管の突出部の中心線を特定し、突出部中心線から分岐する中心線を特定する。そして、制御装置１０２は、分岐中心線に対応する血管の３次元血管データに対して、中心線から血管の周方向、中心線から血管の径方向、中心線方向を座標軸とした円筒座標系を定義し、該円筒座標系で表された血管データを、直交座標系の血管データに変換し、直交座標系の血管データにおいて、中心線方向の座標軸の第一の座標値における径方向の座標軸の座標値と、中心線方向の座標軸の第二の座標値にお
