TY - JOUR
T1 - Radiation effects on the performance of CMOS photodiode array detectors and the role of gain-offset corrections
AU - Kim, Ho Kyung
AU - Cho, Min Kook
AU - Achterkirchen, Thorsten
AU - Lee, Wonho
N1 - Funding Information:
Manuscript received June 27, 2008; revised November 25, 2008. Current version published June 10, 2009. This work was supported by the Korea Research Foundation Grant ("KRF-2008-313-D01339) and the Basic Research Program of the Korea Science & Engineering Foundation (R01-2006-000-10233-0) funded by the Korean Government. *H. K. Kim was the corresponding author for this article. *H. K. Kim and M. K. Cho are with the Mechanical Engineering Department, Pusan National University, Busan 609-735, Korea (e-mail: hokyung@pusan.ac.kr; mk2000@pusan.ac.kr)..
PY - 2009/6
Y1 - 2009/6
N2 - We report the observation of performance degradation in a detector consisting of a phosphor screen and a CMOS (complementary metal-oxide- semiconductor) photodiode array under the continuous irradiation of 45-kVp x-rays. The performance was assessed in terms of dark pixel signal, dynamic range, modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). From the measurement results, it has been observed that the increase of dark pixel signal and the related noise gradually reduces the dynamic range as the cumulative input exposure to the detector increases. Severe degradation in NPS was observed, which gives rise to reduction in DQE as the cumulative input exposure increases. With carefully updated offset and gain correction, however, we can overcome the detrimental effects of increased dark current on NPS and DQE.
AB - We report the observation of performance degradation in a detector consisting of a phosphor screen and a CMOS (complementary metal-oxide- semiconductor) photodiode array under the continuous irradiation of 45-kVp x-rays. The performance was assessed in terms of dark pixel signal, dynamic range, modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). From the measurement results, it has been observed that the increase of dark pixel signal and the related noise gradually reduces the dynamic range as the cumulative input exposure to the detector increases. Severe degradation in NPS was observed, which gives rise to reduction in DQE as the cumulative input exposure increases. With carefully updated offset and gain correction, however, we can overcome the detrimental effects of increased dark current on NPS and DQE.
KW - CMOS detector
KW - CMOS devices
KW - Detective quantum efficiency
KW - Digital radiography
KW - Flat-field correction
KW - Image evaluation
KW - Image sensors
KW - Noise-power spectrum
KW - Radiation effects
KW - X-ray imaging
UR - http://www.scopus.com/inward/record.url?scp=67649210508&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=67649210508&partnerID=8YFLogxK
U2 - 10.1109/TNS.2009.2014232
DO - 10.1109/TNS.2009.2014232
M3 - Article
AN - SCOPUS:67649210508
SN - 0018-9499
VL - 56
SP - 1179
EP - 1183
JO - IEEE Transactions on Nuclear Science
JF - IEEE Transactions on Nuclear Science
IS - 3
M1 - 5075992
ER -