| US 7,573,038 B2 | ||
| Radiation image pickup apparatus, radiation image pickup system, their control method and their control program | ||
| Keigo Yokoyama, Honjo (Japan); Tadao Endo, Honjo (Japan); Toshio Kameshima, Kumagaya (Japan); Tomoyuki Yagi, Honjo (Japan); and Katsuro Takenaka, Saitama-ken (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Aug. 11, 2006, as Appl. No. 11/502,541. | ||
| Claims priority of application No. 2005-236773 (JP), filed on Aug. 17, 2005; and application No. 2006-215855 (JP), filed on Aug. 08, 2006. | ||
| Prior Publication US 2007/0040099 A1, Feb. 22, 2007 | ||
| Int. Cl. H04N 5/32 (2006.01); H05G 1/64 (2006.01) | ||
| U.S. Cl. 250—370.09 [348/E5.081; 378/98.8; 378/98.12] | 11 Claims |
| 1. A radiation image pickup apparatus for photographing a radiation image comprising:
a detection unit in which a plurality of conversion elements, each converting radiation into charges, are two-dimensionally
arranged;
a driving circuit for driving said detection unit;
a reading circuit for reading an electric signal based on the charges from said detection unit;
a control unit for controlling said detection unit, said driving circuit and said reading circuit, wherein said control unit
selectively executes a first reading operation reading a first signal value from said detection unit on which the radiation
has been irradiated, a second reading operation reading a second signal value from said detection unit without being irradiated
by the radiation before the first reading operation, and a third reading operation reading a third signal value from said
detection unit without being irradiated by the radiation after the first reading operation; and
a signal processing unit processing the electric signal output from said reading circuit, wherein said signal processing unit
subtracts a signal value acquired by the second signal value and the third signal value from the first signal value, and
wherein said signal processing unit subtracts, from the first signal value, the signal value derived by adding together the
second signal value and the third signal value with weighting according to a frame rate of the photographing.
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