Radiographic apparatus and radiation detection signal processing method
AssigneeShimadzu Corporation
InventorShoichi Okamura
Life of this patent
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Abstract
Corrected X-ray detection signals are obtained by removing lag-behind parts through a recursive computation based on initial values determined from lag signal value (step T2). Thus, the lag-behind parts can be removed by taking into consideration lag signal values remaining at a starting point of the recursive computation. The lag signal values are dependent on the characteristic of an FPD (flat panel X-ray detector). By removing the lag-behind parts, with the lag signal values taken into consideration, the lag-behind parts are removed from X-ray detection signals with increased accuracy, without being influenced by the characteristic of the FPD.
Claims19
A radiographic apparatus for obtaining radiographic images based on radiation detection signals, comprising:
- radiation emitting means for emitting radiation toward an object under examination;
- radiation detecting means for detecting radiation transmitted through the object under examination;
- and
- signal sampling means for taking radiation detection signals from the radiation detecting means at predetermined sampling time intervals;
- said apparatus obtaining radiographic images based on the radiation detection signals outputted from the radiation detecting means at the predetermined sampling time intervals as radiation is emitted to the object under examination;
- said apparatus further comprising:
- time lag removing means 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 exponential function or a plurality of exponential functions with different attenuation time constants;
- and
- initial value determining means for determining initial values for the recursive computation based on lag signal values remaining at a starting point of the recursive computation;
- wherein said time lag removing means is arranged to obtain corrected radiation detection signals by removing the lag-behind parts from the radiation detection signals through the recursive computation based on the initial values determined by the initial value determining means.
A radiation detection signal processing method for taking, at predetermined sampling time intervals, radiation detection signals generated by irradiating an object under examination, and performing a signal processing to obtain radiographic images based on the radiation detection signals outputted at the predetermined sampling time intervals, said method comprising the steps of:
- 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 exponential function or a plurality of exponential functions with different attenuation time constants;
- determining initial values for the recursive computation based on lag signal values remaining at a starting point of the recursive computation, when performing the recursive computation;
- and
- obtaining corrected radiation detection signals by removing the lag-behind parts through the recursive computation based on the initial values.
Dependencies are inferred from the claim text.