2006 Fiscal Year Final Research Report Summary
A Super High-Sensitivity Imaging for Photon Counting Using an Adaptively Quantized Correlated Multiple Sampling
| Project/Area Number |
16206035
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electron device/Electronic equipment
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| Research Institution | Shizuoka University |
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Principal Investigator |
SHOJI Kawahito Shizuoka University, Research Institute of Electronics, Professor, 電子工学研究所, 教授 (40204763)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Photon Counting / Image Sensor / Low-Light-Level Imaging / Noiseless Detection / Wide Dynamic Range |
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| Research Abstract |
In this study, a super high-sensitivity image sensor using a new noise reduction method called adaptively quantized correlated multiple sampling has been proposed and demonstrated through the theoretical analysis and implementation of image sensor chips. A switched capacitor amplifier whose gain is given by the capacitance ratio of the input capacitance to feedback capacitance is analyzed as a frontend circuit of the column parallel signal readout circuits and it is found that a very low-noise signal readout is possible if the freeze noise component of the frontend amplifier is cancelled in the second stage using a two-stage noise cancelling architecture. The effect of the noise cancelling has been demonstrated with the implementation of a prototype image sensor chip. By extending this idea to a pre-amplified correlated multiple sampling, an extremely low-noise signal readout circuit has been proposed. A noise analysis of the readout circuits with correlated multiple sampling shows that the thermal noise can be greatly reduced by increasing the pre-amplifier gain and the number of sampling. The input-referred noise level can be reduced to 0.2 electrons if the pre-amplifier gain of 32 and the integration times of 16 are used. The most severe problem in CMOS image sensors is an anomalously large noise generated in the in-pixel source follower amplifier, so-called random telegraph signal (RTS) noise. Techniques for reducing the RTS noise is investigated and it is found that a histogram-based noise RTS noise reduction method can effectively reduce the RTS noise with relatively slow relaxation rate. A technique for achieving both extremely low-noise readout and wide linear dynamic range is also proposed and its effectiveness is confirmed with noise analysis.
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Research Products
(44 results)
