Bio-Rad eBook - 2019 - 15

Meet the Innovators:

Inside Bio-Rad's Digital Imaging Lab
Steven Swihart
What is your role at Bio-Rad?
I'm the Advanced Engineering Manager in the Life
Science Group. We work on developing things from
the initial ideas to the point that they mostly work
and can be handed off to engineering.
How did you explore the problem
of increasing sensitivity?
Sensitivity is a lot of things, all driven by signal to
noise. In my mind, the most relevant explanation is
the ability to see a really rarefied signal plenty clearly
above any background. There's many ways to
approach increasing sensitivity. You could use a faster
lens or a larger sensor. You could have a sensor with
better dark current or lower read noise. So, we looked
at several different ways to approach the problem.
What were some challenges in
reducing background noise?
For quantitation purposes, it's completely irrelevant
what the source of the noise is; whether it's from
the sample itself, or if it's from anything inside of the
system, like an electronic source of noise, or just
a diffuse scatter, from some surface somewhere,
or something glowing. Doesn't matter. It all ends
up being noise that can be seen in the customer's
picture, so we needed to identify and address all
the sources.
Are there particular noise challenges
with	different	imaging	modes?
We had to ask ourselves a number of questions in
developing the fluorescence capabilities. They all
really came down to this: If you put the sample down
anywhere on the imaging surface, do you get the
same signal to background for any given band?

Steven Swihart, MSME/MSAE,
Advanced Engineering Manager,
Life Science Research, Bio-Rad Laboratories

"When you set out to beat
film with a digital imager, you
have to allow the customer to do
all the things they can do with
film-and more."
Are there any other image artifacts that have
appeared regardless of the source? We had to try
all of the spectral channels with a whole series of
different stains to make sure that there was nothing
untoward happening, and that the customer can
place a sample anywhere on the tray and a given
band will give the same intensity.
Can	you	give	us	an	example	of	a	specific	noise	
problem you tackled and the solution you came
up with?
As we were working our way through the noise
problems in the fluorescence channels, we

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Bio-Rad eBook - 2019

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