Re: illumination


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

--- In MSG-1@..., "a_van_belle" <a.van.belle@h...> wrote:
Here are my two pennies:

MSG (SEVERI) does send 10 bits grey values (0…1023). Not all these
values are used however.
The minimum value for any channel on MSG-1 is currently 51 (0..1023)

Because of the JPG limitations MDM scales these down to 256.
If there was enough interest, the full ten bits could be delivered
in the Professional version of the MSG Data Manager. Most present-
day image formats and processing tools can only handle 8-bit images,
indeed they eye can only see about 6 bits.

Applying
a gamma on a low light image does give poor results.
But under MDM's advanced setup you can change the min and max
value for every channel separate. This way the 256 grey values are
better distributed and gamma can be applied, depending on the season.

Seasonal adjustments are an excellent idea! The default values of
gamma and minimum level are carefully chosen so that black is black,
and a single level change above black in the 0..1023 domain will be
reflected as a single level change in the 8-bit final image.

[]
Here are my values:
Ch01=MAX=891,MIN=43,GAM=140
Ch02=MAX=806,MIN=60,GAM=145
Ch03=MAX=710,MIN=43,GAM=100
[]
Greetings,
Arne van Belle
It's great to hear the results of your experiments, but why do you
set the black level on these channels different to what is
transmitted (i.e. 51)?

A word of warning to anyone making such adjustments in to ensure
that your monitor is correctly - see:

http://www.jasc.com/monitor1.asp

Cheers,
David

Join MSG-1@groups.io to automatically receive all group messages.