Re: illumination


a_van_belle
 

Here are my two pennies:

MSG (SEVERI) does send 10 bits grey values (0…1023). Not all these
values are used however.
Because of the JPG limitations MDM scales these down to 256. 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.
Using XRIT2PIC (which can handle the full 10 bits) I determined the
most used Min and Max value for every channel. By setting these in
Advanced setup, MDM does utilise the available spectrum much better.
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
Ch04=MAX=756,MIN=53,GAM=100
Ch05=MAX=742,MIN=86,GAM=100
Ch06=MAX=645,MIN=74,GAM=100
Ch07=MAX=829,MIN=74,GAM=100
Ch08=MAX=801,MIN=150,GAM=100
Ch09=MAX=799,MIN=88,GAM=100
Ch10=MAX=800,MIN=102,GAM=100
Ch11=MAX=787,MIN=150,GAM=100
Ch12=MAX=822,MIN=68,GAM=135

By the way, automatic equalisation is nice on HRPT images, but can be
annoying on MSG animations !

Greetings,
Arne van Belle

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