University of Arizona, College of Optical Sciences, 1630 E. University Boulevard, Tucson, Arizona 85721, USA.
J Biomed Opt. 2012 Jan;17(1):015002. doi: 10.1117/1.JBO.17.1.015002.
We theoretically develop and experimentally validate the noise characteristics of heterodyne and/or homodyne measurements that are widely used in frequency-domain diffusive imaging. The mean and covariance of the modulated heterodyne output are derived by adapting the random amplification of a temporal point process. A multinomial selection rule is applied to the result of the temporal noise analysis to additionally model the spatial distribution of intensified photons measured by a charge-coupled device (CCD), which shows that the photon detection efficiency of CCD pixels plays an important role in the noise property of detected photons. The approach of using a multinomial probability law is validated from experimental results. Also, experimentally measured characteristics of means and variances of homodyne outputs are in agreement with the developed theory. The developed noise model can be applied to all photon amplification processes.
我们从理论上推导和实验验证了在频域扩散成像中广泛使用的外差和/或同相测量的噪声特性。通过适应时间点过程的随机放大，得出了调制外差输出的均值和协方差。将多项选择规则应用于时间噪声分析的结果，以进一步模拟由电荷耦合器件 (CCD) 测量的增强光子的空间分布，结果表明 CCD 像素的光子探测效率在探测光子的噪声特性中起着重要作用。使用多项概率定律的方法已通过实验结果得到验证。此外，同相输出的均值和方差的实验测量特性与所发展的理论相符。所开发的噪声模型可应用于所有光子放大过程。
