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version 2.0 rev 18 Feb 2021

2.3.1 Spurious Noise Filter

The Spurious Noise ltercorrectsforpixelsthatwouldotherwiseappearasspurious‘saltandpepper’noise

spikes in the image. The appearance of such noisy pixels is analogous to the situation of Clock Induced Charge

(CIC) noise spikes in EMCCD cameras, in that the overall noise of the sensor has been reduced to such a low

level, that the remaining small percentage of spurious, high noise pixels can become an aesthetic issue. The

lteractivelycorrectssuchhighnoisepixels,replacingthemwiththemeanvalueoftheneighbouringpixels

Theltercanbeswitchedonandobytheuserpriortodataacquisition.

Figure 11: DemonstrationofSpuriousNoiseFilter(FilterOnleft,FilterO,Right)onadarkimage,20msexposuretime,200MHz(x2

halves) readout speed

2.3.2 Blemish Correction

This Blemish Correction lteridentiesandcompensatesforthreetypesofblemishesduringtheFPGA

processing step:

1. Hot Pixel’s

2. Noisy Pixel’s

3. Unresponsive Pixel’s

sCMOS sensors are particularly susceptible to hot pixel blemishes. These are spurious noise pixels that have

signicantlyhigherdarkcurrentthantheaverage.ThroughdeepTEcoolingofthesensor(e.g.-30

C in the

Neo),itispossibletodramaticallyminimizetheoccurrenceofsuchhotpixelswithinthesensor,meaningthat

these pixels can still be used for useful quantitative imaging. However, if deep cooling cannot be achieved it is

necessarytouseinterpolativelterstominimizethehotpixelblemishes.Theseltersworkbytakingthemean

of the surrounding 8 pixel values and replacing this hot pixel blemish with this mean value. Such interpolation

over pixel blemishes can be detrimental in some applications that depend on total quantitative integrity over a

limitedsetofpixels,forexampleinlocalizationbasedsuper-resolutionmicroscopy(suchasPALMandSTORM

techniques)andastronomy.Intheseapplicationsitisessentialfortheusertobeabletoswitchointerpolative

corrections.

Furthermore, having access to the location of these blemishes allows an accurate map of ‘good’ pixels to be

determined by the user. A new service allows the end user to request a ‘hot pixel map’ of their sCMOS sensor

from Andor. This map will be generated based on the experimental conditions outlined by the end user.

From the latest general release of Andor SDK3 (version 3.7.30004) and Solis (version 4.24.30004) blemish

correctioncanbeswitchedonandobytheuser.RefertotheSDKandSolisUserGuideandhelpinformation

for instructions.

Andor Technology Zyla sCMOS 4.2 PLUS User Manual

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