Abstract: An image pickup unit is disposed so as to be able to obtain a scan projection image of an inspection subject from each of a vertical direction and a horizontal direction. An X-ray absorption coefficient of an object in the inspection subject is obtained from the vertical scan projection image and the horizontal scan projection image. It is determined whether there is a threat in the inspection subject on the basis of the X-ray absorption coefficient. Furthermore, a CT image is obtained by moving the image pickup unit around the inspection subject. It is determined whether there is a threat in the inspection subject, on the basis of the CT values of the CT image.

Abstract: An image pickup unit is disposed so as to be able to obtain a scan projection image of an inspection subject from each of a vertical direction and a horizontal direction. An X-ray absorption coefficient of an object in the inspection subject is obtained from the vertical scan projection image and the horizontal scan projection image. It is determined whether there is a threat in the inspection subject on the basis of the X-ray absorption coefficient. Furthermore, a CT image is obtained by moving the image pickup unit around the inspection subject. It is determined whether there is a threat in the inspection subject, on the basis of the CT values of the CT image.