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Comment
. 2012 Aug 15;590(16):3641-2.
doi: 10.1113/jphysiol.2012.237040.

New light on photon detection

Leon Lagnado  1
Affiliations
Comment

New light on photon detection

Leon Lagnado. J Physiol. .
No abstract available

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Figures

Figure 1
Figure 1. Detecting a photon above noise
A, top, the response of a rod to a single photon in the absence of noise. Below are shown simulated responses in the presence of noise with a SNR of 3 (black) and 6.5 (red). The two responses are normalized to the amplitude of the noise, which has a standard deviation of 0.33. Thus when the SNR is 3, the mean response to a single photon is 1. The horizontal green line shows a threshold for photon detection of 1.3. B, distribution of responses to repeated trials in which half do not lead to photon absorption (the peak centred on zero) and half lead to absorption of one photon. Note that the response to a single photon is itself variable, with a standard deviation of 0.33 times the mean. With a SNR of 3, a relative threshold of 1.3 would reject almost all the noise and prevent detection of false positives (dotted trace), but the majority of single photon events would also be lost (thinner solid trace). The same threshold operating on responses with a SNR of 6.5 would detect a much larger fraction of absorbed photons.
See this image and copyright information in PMC

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