| 摘要 |
PURPOSE: To obtain a high quality image having a wide dynamic range by disposing an absorber for reducing the quantity of photon impinging on the incident plane of a sensor at a specific position among a plurality of sensors arranged in an array thereby eliminating the effect of saturation of the sensor. CONSTITUTION: A sensor array 1 is a line sensor comprising radiation sensors S arranged in four rows and a plurality of columns wherein an absorber la for reducing the incident quantity of radiation by a factor of about 2 i.s formed on the incident plane of sensors S in the first row Ll. The sensor 1 is scanned stepwise by a scanning means 2 and the output from each sensor S is fed through a counter circuit 3 to a processing section 4. The counter circuit 3 connected with the first row L1 of the sensor 1 is connected, on the output side thereof, with a comparing section 5. The comparing section 5 corrects the output from the sensors S in the first row L1 using the reduction rate of dose determined by the absorber 1a and compares the output from the circuit 3 with a reference value Th. The comparison results are delivered to the processing section 4.
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