Re: [ATM] Video Foucault Testing

["Bob May" <rmay@nethere.com>]

The thing to do here is cut down on the brightness of the LED so
that the camedra doesn't bloom when a uncut image is present.  I
adjust the brightness so that a normal f-ratio mirror just starts
to show  that it is at full brightnes.  This keeps the camera's
brightness control from activating and making life difficult for
you.
I'll also note that the best place in the brightness curve of a
pair of zones is near the black level anyway so this doesn't end
up being a bother anyway.
Gamma correction is something that is rarely available on cameras
anyway as this is the changing of the curve of light response  to
the amount of light that is on the camera's imager.  With the
advent of CCD and CMOS cameras, which have a linear response to
light, the need for gamma correction should bee nil.    I do see
where you can drive the gamma off and get a large response at the
dark levels while everything else is bright and of little
response tho.  Basicall, there are 256 counts in a JPEG image and
by changing the gamma, you can make the blackest 20 counts go all
the way up to mid gray or even more which will make it somewhat
easier to see the differencce in shades of black but not really
help you otherwise as the 20 counts will be done by 6 counts or
more in the final image.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net


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