PROBLEM TO BE SOLVED: To improve operability in measurement of a sharp angle of a hip joint image and to prevent an erroneous diagnosis.SOLUTION: The hip joint image is displayed on the monitor screen of a display part, and a reference auxiliary line passing through left and right tear drop lower ends, an oblique auxiliary line passing through the right tear drop lower end and a right acetabular outer side edge, and an oblique auxiliary line passing through the left tear drop lower end and a left acetabular outer side edge are drawn. The formula of a straight line L which passes through an end point equivalent to the right side of a human body of the reference auxiliary line and is vertical to the reference auxiliary line is obtained (step S25), the coordinates of intersections of the reference auxiliary line and the respective oblique auxiliary lines are respectively obtained (steps S26, S27), and the one at a shorter distance from the straight line L is determined as the oblique auxiliary line equivalent to the right side of the human body relatively (step S28). An angle formed by the oblique auxiliary line equivalent to the right side of the human body and the reference auxiliary line is defined as a right sharp angle (step S29), and an angle formed by the oblique auxiliary line equivalent to the left side of the human body and the reference auxiliary line is defined as a left sharp angle (step S30).COPYRIGHT: (C)2010,JPO&INPIT【課題】股関節画像のシャープ角の計測における操作性を向上させるとともに、誤診を防止する。【解決手段】股関節画像を表示部のモニタ画面に表示させ、左右の涙痕下端を通る基準補助線、右涙痕下端と右臼蓋外側縁とを通る斜め補助線、左涙痕下端と左臼蓋外側縁とを通る斜め補助線を描画する。基準補助線の人体の右側に相当する端点を通り基準補助線に垂直な直線Lの式を取得し(ステップS25)、基準補助線と各斜め補助線との交点の座標をそれぞれ取得し(ステップS26,S27)、直線Lからの距離が小さい方を、相対的に人体の右側に相当する斜め補助線であると判定する(ステップS28)。人体の右側に相当する斜め補助線と基準補助線とのなす角度を右シャープ角とし(ステップS29)、人体の左側に相当する斜め補助線と基準補助線とのなす角度を左シャープ角とする(ステップS30)。【選択図】図7
