Problem to be solved: to improve the accuracy and robustness of the tracking of the attention part which moves in the living body.The organ position estimation unit 50 obtains the estimated position of the organ in the biological image based on the past movement of the organ. An organ contour estimating part 52 searches an outline point corresponding to a plurality of control points representing the contour shape of the organ in the region corresponding to the estimated position, and obtains the estimated contour of the organ based on the contour point. The diseased section tracking section 54 obtains the position of the attentional portion from the estimated contour based on the previously obtained sample data on the positional relationship between the contour of the organ and the attentional portion interlocked with the organ.The organ contour estimation part 52 is a shape model which represents the contour shape by the sum of the linear shape of the reference shape and the plurality of deformation modes, and it calculates the coefficient of the deformation mode of the linear combination based on only the corresponding contour point in the control point, and it is given in the processing The estimated contour is obtained by repeating the process of correcting the position of the control point from the snack method based on the energy minimization principle for contour shape.Diagram【課題】生体内を運動する注目部分の追跡の精度及びロバスト性の向上を図る。【解決手段】臓器位置推定部50は臓器の過去の動きに基づき生体像における臓器の推定位置を求める。臓器輪郭推定部52は推定位置に対応した領域にて、臓器の輪郭形状を表す複数の制御点それぞれに対応して輪郭点を探索し、輪郭点に基づいて臓器の推定輪郭を求める。患部追跡部54は、臓器の輪郭と当該臓器に連動する注目部分との位置関係についての予め取得された標本データに基づき、推定輪郭から注目部分の位置を求める。臓器輪郭推定部52は輪郭形状を基準形状と複数の変形モードの線形結合との和で表す形状モデルにて、制御点のうち明瞭な輪郭点に対応するもののみに基づき線形結合の変形モードの係数を求める処理と、当該処理で与えられる制御点の位置を輪郭形状に関するエネルギー最小化原理に基づくSNAKE法より修正する処理とを繰り返して推定輪郭を求める。【選択図】図1
