PROBLEM TO BE SOLVED: To acquire in a short time an image that can suppress variation in image quality by a scattered ray by not executing repetitive processing or substantially reducing a repetition frequency of the processing.SOLUTION: A radiation imaging apparatus includes: a radioactive ray source for irradiating a subject with a radioactive ray a radioactive ray detector for detecting intensity distribution of the radioactive ray passing through the subject an extraction part for extracting a high frequency component in at least one of a space axial direction and a time axial direction with regard to the intensity distribution of the radioactive ray and a thickness distribution calculation part for obtaining the thickness distribution of the subject based on the high frequency component extracted by the extraction part.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2019,JPO&INPIT【課題】反復処理を行わないか、あるいは処理の反復回数を大きく削減しながら、散乱線による画質変動を抑えた画像を短時間で得る。【解決手段】被写体に放射線を照射する放射線源と、被写体を通過した放射線の強度分布を検出する放射線検出器と、放射線の強度分布について、空間軸方向および時間軸方向の少なくとも一方の高周波成分を抽出する抽出部と、抽出部が抽出した高周波成分に基づいて被写体の厚さの分布を求める厚さ分布算出部とを有する。【選択図】図4
