CCD riddle: a) signal vs time: linear; b) signal vs variance: non-linear
CCD riddle: a) signal vs time: linear; b) signal vs variance: non-linear
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DOI：
10.1117/12.671457
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发表时间：
2006-06
期刊：
影响因子：
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通讯作者：
M. Downing;D. Baade;P. Sinclaire;S. Deiries;F. Christen
中科院分区：
文献类型：
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作者：
M. Downing;D. Baade;P. Sinclaire;S. Deiries;F. Christen
光子传输曲线是标定、表征和优化CCDs性能的最有价值的工具之一。它的主要目的是确定CCD系统的转换增益，由此确定许多其他性能参数，如读取噪声、暗电流、QE、全势垒等。最近对不同制造商的ccd的测量表明，光子转移曲线是非线性的(超过15%)，在高信号电平下，方差逐渐变小，而不是简单的光子散粒噪声所预测的。令人费解的是，信号线性度很好，而且没有受到影响。本文报道了对CCD成像区域进行的一次调查，找出了非线性的来源。此外，空间自相关分析表明，非线性背后的机制是由于图像区域内像素之间电荷的扩散或共享。作者只对这一现象进行了描述，并邀请所有人帮助解释。
Photon transfer curve is one of the most valuable tools for calibrating, characterizing, and optimizing the performance of CCDs. Its primary purpose is to determine the conversion gain of the CCD system, from which many of the other performance parameters such as read noise, dark current, QE, full well etc. are determined. Recent measurements on CCDs from different manufacturers have revealed that the photon transfer curve is non-linear (in excess of 15%) with the variance progressively becoming less at high signal levels than that predicted by simple photon shot noise. The puzzling thing is that the signal linearity is excellent and unaffected. This paper reports on the investigation which has isolated the source of the non-linearity to the CCD image area. Additionally, spatial autocorrelation analysis shows that the mechanism behind the non-linearity is due to spreading or sharing of charge between pixels in the image area. The authors only have a description of the phenomenon and invite all to help with an explanation.