Patent Document ID: 9084568
Application ID: 13387827
Patent Status: 1

Claim One:
1. A radiation imaging apparatus, comprising: a radiation emitting source including an X-ray tube radiating an X-rays; a radiation detector detecting the X-rays and outputting, every frame, electric digital two-dimensional data corresponding to incidence of the X-rays to the radiation detector, the X-ray tube and the radiation detector being positioned to be opposed to each other with an object located therebetween; moving means for moving a pair of the X-ray tube and the radiation detector such that the X-rays are scanned to focus on a three-dimensional (3D) referential tomographic plane of the object, the referential tomographic plane being curved in a real space; data acquiring means for acquiring, every frame, the data outputted from the radiation detector while the pair of the X-ray tube and the radiation detector is moved relative to the object by the moving means; image producing means for producing two three-dimensional optimally focused images on the basis of the data acquired by the data acquiring means at different two time points from the same portion to be imaged of the object, the portion to be imaged of the object being optimally focused and reflecting an actual position and shape of the portion therein and being an oral cavity containing a tooth row of the object; aligning means for mutually aligning spatial positions of the two three-dimensional optimally focused images produced by the image producing means at the different two time point; and difference calculating means for calculating differences, pixel by pixel, between the two three-dimensional optimally focused images mutually aligned by the aligning means, wherein the image producing means comprises: referential-plane image reconstructing means for reconstructing, as a referential-plane image, a panoramic image of the tooth row based on the data acquired by the data acquiring means, the panoramic image being produced by projecting the referential tomographic plane onto a detection surface of the detector, tomographic plane setting means for setting a plurality of tomographic planes along the 3D referential tomographic plane in a direction opposed to the 3D referential tomographic plane, pixel value calculating means for calculating pixel values of each of the plurality of tomographic planes, position identifying mean for identifying optimally focused sampling points of the portion being imaged based on image data of both the 3D referential tomographic plane and the plurality of tomographic planes to which the pixel value calculating means provides the pixel values, pixel value providing means for providing the sampling points identified by the position identifying means, with pixel values based on the pixel values at the sampling points corresponding to the panoramic image and being present in a viewing direction from the X-ray tube to the detector via the respective sampling points, tooth row detecting means for detecting the tooth row by recognizing the 3D referential tomographic plane provided at the sampling points to which the pixel values are provided by the pixel value providing means and a characteristic pattern shown by pixel values of the plurality of tomographic planes, classification means for classifying substances every characteristic shown by the same type of substance based on the frequency characteristic at the respective sampling points, and smoothing means for smoothly connecting the substances, classified by the classification means, such that noise is removed from the sampling points of the tooth row decided by the tooth row deciding means.