To synthesize an appropriate long-length image without increasing a burden on a technician in long-length imaging using a plurality of radiation detectors.SOLUTION: An image processing device comprises: image acquisition means for acquiring a radiation image from each of a plurality of detection means including at least first detection means for detecting a radiation and second detection means arranged in a state in which part of the second detection means overlaps with the first detection means； identification information acquisition means for acquiring information for identifying the plurality of detection means； identification means for identifying, on the basis of the acquired identification information, a radiation image acquired by the second detection means； rotation means for rotating the radiation image identified by the identification means； and synthesis means for generating a long-length image by synthesizing the radiation image after being rotated by the rotation means and a radiation image acquired by detection means other than the second detection means.SELECTED DRAWING: Figure 4【課題】複数の放射線検出装置を用いる長尺撮影において、技師の負担を増すことなく、適切な長尺画像を合成することを目的とする。【解決手段】放射線を検出する第１の検出手段と、第１の検出手段と一部が重なった状態で配置された第２の検出手段とを少なくとも含む複数の検出手段それぞれから、放射線画像を取得する画像取得手段と、複数の検出手段を特定する情報を取得する特定情報取得手段と、取得した特定情報に基づいて、第２の検出手段により得られた放射線画像を特定する特定手段と、特定手段により特定された放射線画像を回転する回転手段と、回転手段による回転後の前記放射線画像と、第２の検出手段以外の検出手段により得られた放射線画像と、を合成して長尺画像を生成する合成手段とを有する。【選択図】図４
