An approach to improve the signal-to-noise ratio of active pixel sensor for low-light-level applications
An approach to improve the signal-to-noise ratio of active pixel sensor for low-light-level applications
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DOI：
10.1109/ted.2006.881053
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发表时间：
2006-09-01
影响因子：
3.1
通讯作者：
Shirani, Shahram
中科院分区：
文献类型：
--
作者：
Faramarzpour, Naser;Deen, M. Jamal;Shirani, Shahram
CMOS光电探测器结构紧凑，价格便宜，功耗低，使它们成为许多生物医学应用的良好候选者。然而，这些应用中的许多需要检测低水平光的能力。因此，必须仔细考虑CMOS传感器中的噪声。本文详细分析了有源像素传感器（APS）元件的信号和噪声特性。通过改变积分时间实现了54 dB的最佳信噪比（SNR）。基于APS的严格复位时间分析，提出了感测节点的直流电平作为新的输出信号，这比现有的APS技术对低电平光更敏感。通过改变复位时间，在30 ms的积分时间内可获得56 dB的最佳SNR。这种方法可以实现更高的信噪比相同的APS结构比以前的报告中发现的文献。
CMOS photodetectors are compact, cheap, and of low power, making them good candidates for many biomedical applications. However, many of these applications require the capability of detecting low-level light. Therefore, the noise in CMOS sensors must be carefully considered. This paper presents a detailed analysis of the signal and noise properties in active pixel sensor (APS) elements. An optimum signal-to-noise ratio (SNR) of 54 dB is achieved by varying the integration time. Based on a rigorous reset-time analysis of the APS, the dc level of the sense node is proposed as the new output signal, which is more sensitive to low-level light than existing APS techniques. By varying the reset time, an optimum SNR of 56 dB is achieved for a 30-ms integration time. This approach can achieve higher SNR for the same APS structure than the previous reports found in the literature.