Patent ID: 7760856

Claim:
A radiographic apparatus for obtaining radiographic images based on radiation detection signals, comprising a radiation emitting device for emitting radiation toward an object under examination, a radiation detecting device for detecting radiation transmitted through the object under examination, and a signal sampling device for taking radiation detection signals from the radiation detecting device at predetermined sampling time intervals, said apparatus being constructed to obtain radiographic images based on the radiation detection signals outputted from the radiation detecting device at the predetermined sampling time intervals as radiation is emitted to the object under examination, said apparatus further comprising a time lag removing device for removing lag-behind parts from the radiation detection signals by a recursive computation, on an assumption that a lag-behind part included in each of said radiation detection signals taken at the predetermined sampling time intervals is due to an impulse response formed of a single or a plurality of exponential functions with different attenuation time constants; and an emission control device for controlling timing of emission start and emission stop of said radiation emitting device; characterized in that (A) in a state where the emission control device having caused the radiation emitting device to start emission, said time lag removing device removes the lag-behind parts by recursive computation to obtain corrected radiation detection signals, (B) in response to an instruction for a predetermined operation relating to radiographic imaging, the emission control device causes said radiation emitting device to stop the emission temporarily, the time lag removing device stops the recursive computation temporarily, and said signal sampling device acquires radiation detection signals in time of non-emission due to the temporary stop of the radiation emitting device, and (C) with start of said predetermined operation, the emission control device causes the radiation emitting device to start emission again, and the time lag removing device starts the recursive computation again based on initial values derived from the radiation detection signals in time of said non-emission.