Qiao Li, Wang Mingfu, Jin Zheng
Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, 610209, Sichuan, China.
Sci Rep. 2021 Mar 15;11(1):6058. doi: 10.1038/s41598-021-85511-z.
In order to improve the image quality, it is imperative to conduct the non-uniformity correction of EMCCD, for which the measurement accuracy of the internal electron multiplication gain of each channel is a prerequisite within multi-channel output EMCCD. It is known that the smaller the image standard deviation of each channel, the better the image uniformity, and the closer the calculated multiplier gain is to the real value. In order to minimize the influence of non-uniformity of background between pixels and light response existing in traditional measurement, a comprehensively modified EMCCD multiplication gain measurement is proposed after the working principle of EMCCD is described. The output images of the camera working in the normal CCD mode and EMCCD mode are corrected comprehensively through this method. The experimental results show that after the comprehensive correction, the standard deviation of the output image of each channel within the camera decreases to about one third of the original when the camera works in the normal CCD mode, while it decreases to about one fifth of the original when the camera works in the EMCCD mode, the signal stability is significantly improved, and the measured multiplier gain of each channel is closer to the true value of the detector, which proves the effectiveness of the proposed method.
为了提高图像质量，对电子倍增电荷耦合器件（EMCCD）进行非均匀性校正是势在必行的，对于多通道输出的EMCCD而言，其前提是要测量每个通道内部电子倍增增益的精度。众所周知，每个通道的图像标准差越小，图像均匀性越好，计算得到的倍增增益就越接近真实值。为了将传统测量中像素间背景非均匀性和光响应的影响降至最低，在阐述了EMCCD的工作原理之后，提出了一种经过全面改进的EMCCD倍增增益测量方法。通过该方法对相机在正常电荷耦合器件（CCD）模式和EMCCD模式下工作时的输出图像进行全面校正。实验结果表明，经过全面校正后，相机在正常CCD模式下工作时，每个通道输出图像的标准差降至原来的约三分之一，而在EMCCD模式下工作时，该标准差降至原来的约五分之一，信号稳定性显著提高，且每个通道测量得到的倍增增益更接近探测器的真实值，这证明了所提方法的有效性。
