PROBLEM TO BE SOLVED: To generate, with excellent image quality, monochromatic images equivalent to images obtained by performing X-ray CT photographing of a photographing object with the X-ray of desired effective X-ray energy.SOLUTION: On the basis of data obtained by X-ray CT dual energy photographing of a photographing object, a material density image indicating a virtual density distribution of a basis material of the photographing object in a model indicating the photographing object by the composition of one set of two kinds of basis materials is generated for each basis material, for two or more sets of the basis materials in which at least one of the basis materials constituting a set is different. Then, the pixel value of each pixel of the monochromatic image is obtained by weighting addition of the pixel values of corresponding pixels of the pixel with each other in the respective material density images by a set of the basis materials determined on the basis of information related to the size of the X-ray absorption coefficient of the material indicated by the pixel among the two or more sets of the basis materials.COPYRIGHT: (C)2013,JPO&INPIT【課題】撮影対象を所望の実効X線エネルギーのX線によりX線CT撮影したときに得られる画像に相当するモノクロマチック画像をよい画質で生成する。【解決手段】撮影対象のX線CTデュアルエネルギー撮影により得られたデータに基づいて、撮影対象を2種類1組の基底物質の合成で表すモデルにおける、撮影対象の基底物質の仮想的な密度分布を表す物質密度画像を、組を構成する少なくとも一方の基底物質が異なる2組以上の基底物質について、基底物質毎に生成する。そして、モノクロマチック画像の各画素の画素値を、上記2組以上の基底物質のうち当該画素が表す物質のX線吸収係数の大小に係る情報を基に定められた1組の基底物質による各物質密度画像における当該画素の対応画素の画素値同士を加重加算処理して求める。【選択図】図2
