Title :
3-TFT active pixel sensor with correlated double sampling readout circuit for real-time medical x-ray imaging
Author :
Safavian, N. ; Chaji, G.R. ; Kabir, M.Z. ; Nathan, A. ; Rowlands, J.A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Waterloo Univ., Ont.
Abstract :
This paper presents a current-programmed, current-output active pixel sensor (APS) suitable for real time X-ray imaging (e.g., fluoroscopy) using hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) technology and an appropriate CMOS readout circuit. The proposed pixel circuit can successfully compensate for characteristic variations such as mobility and threshold voltage shift in a-Si:H TFTs. The proposed readout circuit exploits correlated double sampling (CDS) technique not only for reducing the offset current and low frequency noise, but also to reduce the effect of fixed-pattern noise (FPN) on the array operation. The on-pixel amplification reduces the input referred noise to levels that can satisfy the strict requirements for low noise digital fluoroscopy
Keywords :
CMOS integrated circuits; X-ray imaging; amorphous semiconductors; diagnostic radiography; image sensors; readout electronics; silicon; thin film transistors; CMOS readout circuit; Si:H; active pixel sensor; correlated double sampling; digital fluoroscopy; fixed-pattern noise; medical X-ray imaging; thin film transistor; threshold voltage shift; Biomedical imaging; CMOS image sensors; Circuit noise; Image sensors; Low-frequency noise; Noise reduction; Pixel; Sampling methods; Thin film transistors; X-ray imaging;
Conference_Titel :
Circuits and Systems, 2006 IEEE North-East Workshop on
Conference_Location :
Gatineau, Que.
Print_ISBN :
1-4244-0416-9
Electronic_ISBN :
1-4244-0417-7
DOI :
10.1109/NEWCAS.2006.250919
