A Stochastic Model for Electron Multiplication Charge-Coupled Devices – From Theory to Practice

Michael Hirsch,Michael P Hobson,Marisa L Martin-Fernandez,Daniel J Rolfe,Richard J Wareham,Chin-Tu Chen

doi:10.1371/journal.pone.0053671

Michael Hirsch, Michael P Hobson + Show 4 more

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https://doi.org/10.1371/journal.pone.0053671

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Abstract

Electron multiplication charge-coupled devices (EMCCD) are widely used for photon counting experiments and measurements of low intensity light sources, and are extensively employed in biological fluorescence imaging applications. These devices have a complex statistical behaviour that is often not fully considered in the analysis of EMCCD data. Robust and optimal analysis of EMCCD images requires an understanding of their noise properties, in particular to exploit fully the advantages of Bayesian and maximum-likelihood analysis techniques, whose value is increasingly recognised in biological imaging for obtaining robust quantitative measurements from challenging data. To improve our own EMCCD analysis and as an effort to aid that of the wider bioimaging community, we present, explain and discuss a detailed physical model for EMCCD noise properties, giving a likelihood function for image counts in each pixel for a given incident intensity, and we explain how to measure the parameters for this model from various calibration images.

Highlights

Electron multiplication (EM) charge-coupled devices (CCD) are used to take images under low-light conditions and for photoncounting experiments
The detector component of the Electron multiplication charge-coupled devices (EMCCD) consists of a number of bins
During the shift process there is a chance that unwanted electrons are created, which is known as clock induced charge (CIC)

Summary

Introduction

Electron multiplication (EM) charge-coupled devices (CCD) are used to take images under low-light conditions and for photoncounting experiments. They are applied in a wide range of scientific fields, such as single molecule microscopy, astronomy, spectroscopy and biomedical imaging. Imaging under low-light conditions presents the problem that the signal can be low compared to the readout noise. EMCCDs overcome this problem by amplifying the signal in an electron-multiplication register. This reduces the effective readout noise to less than one electron. This comes at the price, of introducing an additional source of noise

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