Patent ID: 8824629

Claim:
A radiation imaging system comprising: a first grating for passing radiation from a radiation source to form a first periodic pattern image; an intensity modulator for providing intensity modulation to the first periodic pattern image to form at least one second periodic pattern image; a radiation image detector for detecting the second periodic pattern image to produce image data; a phase shift differential image generator for producing a phase shift differential image based on the image data; a staircase data generator for obtaining one or more boundaries, at each of which a value changes from π/2 to −π/2 or from −π/2 to π/2, in each of a first phase shift differential image, produced by the phase shift differential image generator in absence of a subject in preliminary imaging, and a second phase shift differential image, produced by the phase shift differential image generator in presence of the subject in main imaging, and producing first staircase data and second staircase data each changing by π or −π when crossing the boundary in a predetermined direction; a staircase data adder for adding the first staircase data to the first phase shift differential image to produce first added phase shift differential image and adding the second staircase data to the second phase shift differential image to produce second added phase shift differential image; and a subtraction processing section for subtracting the first added phase shift differential image from the second added phase shift differential image to produce a corrected phase shift differential image.