An apparatus according to the invention includes a response coefficient to dose relationship memory for storing, in advance, a relationship of correspondence between intensities of an exponential function for impulse response and X-ray doses. The intensities of the exponential function determine conditions relating to an impulse response in a recursive computation performed to remove lag-behind parts from X-ray detection signals outputted from an FPD, thereby to obtain corrected X-ray detection signals. An impulse response coefficient setter sets an impulse response coefficient corresponding to an X-ray dose for an object under examination based on the relationship of correspondence between intensities of the exponential function and radiation doses. A time lag remover performs the recursive computation for time lag removal, with the intensity of an exponential function set to correspond to the X-ray dose for the object under examination. Thus, a lag-behind part is removed properly from each X-ray detection signal.
Radiographic apparatus and radiation detection signal processing method