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Photophysical image analysis for sCMOS cameras: Noise modelling and estimation of background parameters in fluorescence-microscopy images

Mohanta, Dibyajyoti LU ; Kunnath, Radhika ; Clarkson, Erik LU orcid ; Dvirnas, Albertas LU ; Westerlund, Fredrik and Ambjörnsson, Tobias LU (2025) In PLOS ONE 20(11).
Abstract
Fluorescence microscopy is an effective tool for imaging biological samples, yet captured images often contain noises, including photon shot noise and camera read noise. To analyze biological samples accurately, separating background pixels from signal pixels is crucial. This would ideally be guided by the knowledge of a parameter called the Poisson parameter, 𝜆bg, representing the mean number of photons collected in a background pixel (for the case when quantum efficiency = 1 and the dark current is negligible). This study introduces a method for estimating 𝜆bg, from an image which contains both background and signal pixels, using probabilistic noise modeling for an sCMOS camera. The approach incorporates... (More)
Fluorescence microscopy is an effective tool for imaging biological samples, yet captured images often contain noises, including photon shot noise and camera read noise. To analyze biological samples accurately, separating background pixels from signal pixels is crucial. This would ideally be guided by the knowledge of a parameter called the Poisson parameter, 𝜆bg, representing the mean number of photons collected in a background pixel (for the case when quantum efficiency = 1 and the dark current is negligible). This study introduces a method for estimating 𝜆bg, from an image which contains both background and signal pixels, using probabilistic noise modeling for an sCMOS camera. The approach incorporates Poisson-distributed photon shot noise and sCMOS camera read noise modelled with a Tukey-Lambda distribution. We apply a chi-square test and a truncated fit technique to estimate 𝜆bg directly from a general sCMOS image, with camera parameters determined through calibration experiments. We validate our method by comparing 𝜆bg estimates in images captured by sCMOS and EMCCD cameras for the same field of view. Our analysis shows strong agreement for low to moderate exposure images, where estimated values for 𝜆bg align well between the sCMOS and EMCCD images. Based on our estimated 𝜆bg, we perform image thresholding and segmentation using our previously introduced procedure. Our publicly available software provides a platform for photophysical image analysis for sCMOS camera systems. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLOS ONE
volume
20
issue
11
article number
e0335310
pages
20 pages
publisher
Public Library of Science (PLoS)
external identifiers
  • pmid:41187169
  • scopus:105020733640
ISSN
1932-6203
DOI
10.1371/journal.pone.0335310
language
English
LU publication?
yes
id
858a9764-d502-4fb7-9be6-5423df47f9ab
date added to LUP
2025-11-06 15:56:29
date last changed
2025-11-21 04:01:06
@article{858a9764-d502-4fb7-9be6-5423df47f9ab,
  abstract     = {{Fluorescence microscopy is an effective tool for imaging biological samples, yet captured images often contain noises, including photon shot noise and camera read noise. To analyze biological samples accurately, separating background pixels from signal pixels is crucial. This would ideally be guided by the knowledge of a parameter called the Poisson parameter, 𝜆<sub>bg</sub>, representing the mean number of photons collected in a background pixel (for the case when quantum efficiency = 1 and the dark current is negligible). This study introduces a method for estimating 𝜆<sub>bg</sub>, from an image which contains both background and signal pixels, using probabilistic noise modeling for an sCMOS camera. The approach incorporates Poisson-distributed photon shot noise and sCMOS camera read noise modelled with a Tukey-Lambda distribution. We apply a chi-square test and a truncated fit technique to estimate 𝜆<sub>bg</sub> directly from a general sCMOS image, with camera parameters determined through calibration experiments. We validate our method by comparing 𝜆<sub>bg</sub> estimates in images captured by sCMOS and EMCCD cameras for the same field of view. Our analysis shows strong agreement for low to moderate exposure images, where estimated values for 𝜆<sub>bg</sub> align well between the sCMOS and EMCCD images. Based on our estimated 𝜆<sub>bg</sub>, we perform image thresholding and segmentation using our previously introduced procedure. Our publicly available software provides a platform for photophysical image analysis for sCMOS camera systems.}},
  author       = {{Mohanta, Dibyajyoti and Kunnath, Radhika and Clarkson, Erik and Dvirnas, Albertas and Westerlund, Fredrik and Ambjörnsson, Tobias}},
  issn         = {{1932-6203}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{11}},
  publisher    = {{Public Library of Science (PLoS)}},
  series       = {{PLOS ONE}},
  title        = {{Photophysical image analysis for sCMOS cameras: Noise modelling and estimation of background parameters in fluorescence-microscopy images}},
  url          = {{http://dx.doi.org/10.1371/journal.pone.0335310}},
  doi          = {{10.1371/journal.pone.0335310}},
  volume       = {{20}},
  year         = {{2025}},
}