Patent ID: 7135681

Claim:
A signal detecting method for detecting a charge signal outputted from a radiation image detector, which is configured to receive radiation carrying a radiation image to record said image therein and to output a charge signal in accordance with said image recorded therein, as an image signal representing said radiation image, said method comprising the steps of: (1) integrating said charge signal outputted from said radiation image detector with an integral amplifier, (2) inputting said integrated electrical signal to a low pass filter, (3) holding said filtered electrical signal outputted from said low pass filter with a sample/hold circuit to detect said filtered electrical signal as an image signal representing said radiation image, (4) resetting said integral amplifier, and (5) repeating said steps (1) to (4), wherein the time constant of said low pass filter is altered such that said time constant during the time period between said resetting of said integral amplifier and the initiation of the next integration is set smaller than that during the time period between the initiation of said inputting of said integrated electrical signal to said low pass filter and said holding of said filtered electrical signal.