PROBLEM TO BE SOLVED: To provide a radiotherapy apparatus controller allowing enhancement of a detection speed of a marker in a radiation perspective image generated by irradiating radiation to a radiographic subject embedded with the marker.SOLUTION: One luminance difference of luminance differences between a luminance of a certain pixel and luminances of two opposite pixels positioned at a prescribed distance not less than half of a line width of the marker from the certain pixel in the radiation perspective image is calculated in a plurality of different directions passing the certain pixel, information about the largest luminance difference of them is specified about the pixel, and each-pixel luminance difference information holding the information about the luminance difference about the plurality of pixels in the radiation perspective image is created. The pixels decided to be noise of the pixels each having the luminance value not less than a prescribed threshold value are removed in the each-pixel luminance difference information, the pixels that are a marker candidate are specified, the pixels that are the marker candidate are classified into a plurality of areas by combination of the adjacent pixels, and the pixels belonging to an area whose range is not less than a threshold value are specified as the pixels indicating the marker.COPYRIGHT: (C)2012,JPO&INPIT【課題】マーカが埋め込まれた被写体へ放射線を照射して生成された放射線透視画像中のマーカの検出速度を上げることができる放射線治療装置制御装置を提供する。【解決手段】放射線透視画像中における、ある画素からマーカの線幅の半分以上の所定距離に位置する対向する2つの画素の各輝度と、の輝度差のうちの何れか一方の輝度差を、ある画素を通る複数の異なる方向について算出し、そのうちの最も大きい輝度差の情報を当該画素について特定して、当該輝度差の情報を放射線透視画像中の複数の画素について保持した画素毎輝度差情報を作成する。画素毎輝度差情報において輝度差が所定の閾値以上の画素のうちノイズと判定される画素を除去してマーカ候補となる画素を特定し、マーカ候補となる画素について、隣接する画素の纏まりによって複数の領域に分類して、領域の範囲が閾値以上の領域に属する画素を、マーカを示す画素として特定する。【選択図】図1
