Date   

Re: illumination

a_van_belle
 

--- In MSG-1@..., "David Taylor" <david-taylor@b...>
wrote:
The minimum value for any channel on MSG-1 is currently 51 (0..1023)
Looking closely at the 10 bit histogram on current HRIT images I
cannot detect this lower limit anymore. (it was there on the initial
image processing system IIPS)

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.
Saving 10 bits would increase the needed storage space too !

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)?
I forgot to mention that I tweaked the ch1,2,3 values a bit to get a
good balance in the R3G2B1 False Colour images.
False Colour is a matter of taste, but I am very pleased with the new
settings (better than the values I used before).

Below are my Min/Max/Gamma values for FSD (except GOES9=8bit)

G10vis=min9,max688,gam135
G10ir=min150,max910,gam100
G10wv=min150,max625,gam100
G12vis=min0,max886,gam135
G12ir=min150,max975,gam100
G12wv=min150,max644,gam100

These values are chosen to maintain all info and spread it as best as
possible into the saved 256 greyscales.
Note that min150 is the Min value upperlimit, not the value I read on
the histogram !

Greetings
Arne van Belle


Re: illumination

Guy Martin <agm@...>
 

Also the human eye sees in monochrome at low light levels. Rods and cones !!

Cheers, Guy

----- Original Message -----
From: Robert Moore
To: MSG-1@...
Sent: Thursday, November 20, 2003 4:06 PM
Subject: Re: [MSG-1] Re: illumination


Yes I was thinking how I can see as easily at summer noon and after dark in
winter with a full moon. The latter level of illumination is a minute fraction
of the former - yet no MSG vis imagery by moonlight!

Robert


----------

http://www.gordano.com - Messaging for educators.


Re: illumination

maxrpunkt
 

i know that automatic equalization is not reasonable for sequences because of the permanently changing histogramms of the images. that is why i'm doing a 'fixed' histogram equalization. this means i figured out what exactly happens while histogramm equalization of a 12:00 image. this histogram transform is describable by a spline interpolation through a few points (f.e. 20). in this way the resulting image sequences are looking fine. i attached an example of my color composit, where this histogram transform was applied.
max


Re: illumination

Robert Moore
 

Yes I was thinking how I can see as easily at summer noon and after dark in
winter with a full moon. The latter level of illumination is a minute fraction
of the former - yet no MSG vis imagery by moonlight!

Robert

Quoting David Taylor <david-taylor@...>:

Our eyes seem much better at responding to lower levels of light
than the instruments.

Robert,

Our eyes (and ears) have a log response, the scientific instruments
on MSG-1 demand a linear response. If Log (signal) were transmitted
over the link all your prayers would be answered! Ah, assuming the
data source has a low noise and a precisely-set black level, that is!

Cheers,
David



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------------------------------
Professor Robert Moore
Department of Sociology, Social Policy
and Social Work Studies
The University of Liverpool
Eleanor Rathbone Building
Bedford Street South
Liverpool
L69 7ZA

tel and fax: 44 (0) 1352 714456


Re: setup freq's for hotbird

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

--- In MSG-1@..., "gerald_isit2003"
<gerald.ashford@n...> wrote:
i have just got the sky2pc-usb from timestep but cant even get tv
pics from it cant find freq's for lmb transponders etc dish is on
hotbird over 50% sig any help would be welcome
thanks in advance
gerald
See:

http://www.geocities.com/digitalsatuk/hotbird_13e.html
http://www.satmania.com/eng/satchannels/13_0e/hot_bird_6

Look for Hotbird and "Sailing Channel"

Details: 11096 H 3/4 27500

Cheers,
David


Re: illumination

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

Our eyes seem much better at responding to lower levels of light
than the instruments.

Robert,

Our eyes (and ears) have a log response, the scientific instruments
on MSG-1 demand a linear response. If Log (signal) were transmitted
over the link all your prayers would be answered! Ah, assuming the
data source has a low noise and a precisely-set black level, that is!

Cheers,
David


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


setup freq's for hotbird

gerald_isit2003 <gerald.ashford@...>
 

i have just got the sky2pc-usb from timestep but cant even get tv
pics from it cant find freq's for lmb transponders etc dish is on
hotbird over 50% sig any help would be welcome
thanks in advance
gerald


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


Re: illumination

fvalk <fvalk@...>
 

Robert,

I agree with you that much of the information that may be used to visualise
aspects that are there are lost in the visible light channels. For MSG this is
the current situation and for HRPT it has been. We resolved it for HRPT quite
some time ago by developing an algorithm that deals with both visible and
infrared information. It might be a thought for David to consider incorporating
the same principle for MSG as well.
David, what do you think?

Ferdinand

---------- Original Message -----------
From: Robert Moore <rsmoore@...>
To: MSG-1@...
Sent: Thu, 20 Nov 2003 12:32:18 +0000
Subject: [MSG-1] illumination

The differences between the sensitivity of the human eye and onboard
satellite instruments is quite striking with MSG-1 at the moment.
Current visual imagery of Europe obviously shows low levels of
illumination - and indeed darkness north of ... whatever the current
latitude is. Yet here in N. Wales, even under quite heavy cloud,
everything is bright
(if not particularly cheerful). Our eyes seem much better at
responding to lower levels of light than the instruments. On the
other hand, we aren't very good at seeing things by infrared! If I
haven't got this all wrong then a question follows: Are there any ways
in which we might use our software to squeeze a little bit more out
from the visible wavelengths at the darkest parts of the year? I'm
not at all clear about this. I appreciate, of course, that one can't
enhance something that is not there. David (T) and others, do you have
any thoughts on this, or am I wasting everyone's time with the
question? Robert



------------------------------
Robert Moore

tel and fax: 44 (0) 1352 714456


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------- End of Original Message -------


Re: illumination

johnrigsec@...
 

In a message dated 20-11-03 16:10:38 GMT Standard Time,
rsmoore@... writes:

Yes I was thinking how I can see as easily at summer noon and after dark in
winter with a full moon. The latter level of illumination is a minute
fraction
of the former - yet no MSG vis imagery by moonlight!
Robert,

No, MSG will never image by moonlight but at last years EUMETSAT conference
there were serious suggestions about doing just that in the next generation
of
geostationary satellites.

Trouble is that imaging via moonlight requires an enormous aperture
radiometer -
which in turn requires an enormous satellite.

Regards,
John Tellick.
RIG.


Re: illumination

maxrpunkt
 

i don't know if i understood your question correctly, but i think histogram equalization of the visible images could solve your problem.


illumination

Robert Moore
 

The differences between the sensitivity of the human eye and onboard
satellite instruments is quite striking with MSG-1 at the moment. Current
visual imagery of Europe obviously shows low levels of illumination - and
indeed darkness north of ... whatever the current latitude is.
Yet here in N. Wales, even under quite heavy cloud, everything is bright
(if not particularly cheerful). Our eyes seem much better at responding to
lower levels of light than the instruments. On the other hand, we aren't very
good at seeing things by infrared!
If I haven't got this all wrong then a question follows: Are there any ways
in which we might use our software to squeeze a little bit more out from
the visible wavelengths at the darkest parts of the year? I'm not at all clear
about this. I appreciate, of course, that one can't enhance something that is
not there. David (T) and others, do you have any thoughts on this, or am I
wasting everyone's time with the question?
Robert



------------------------------
Robert Moore

tel and fax: 44 (0) 1352 714456


Re: Missing segments

Douglas Deans <douglas@...>
 

David, have the same results, also the missing LRIT segment that is
not reported.
Strangely I have also HRIT 1045 ch9 seg 6 missing, although not
reported. Will dig into the TQ log to see what has happened!

Hello Arne

If you look at my earlier mail from yesterday you will see that I also
reported 10.45 ch9 segment 6 missing. (it was in the missing segment report
as well).


Regards
Douglas.


Re: Missing segments

a_van_belle
 

--- In MSG-1@..., "David Taylor" <david-taylor@b...>
wrote:
Did anyone else just get gaps in the 1100 cycle, or do I have a
local defect?

Missing HRIT & LRIT segments report
Cycle: 1100
msg-ch03, seg: 6
msg-ch05, seg: 6
msg-ch07, seg: 6
msg-ch12, seg: 18 19

I also got a gap in the 1045 LRIT cycle which wasn't reported as a
missing segment (ch 3 seg 2), and may have therefore been one with
bad data.
David, have the same results, also the missing LRIT segment that is
not reported.
Strangely I have also HRIT 1045 ch9 seg 6 missing, although not
reported. Will dig into the TQ log to see what has happened!

But apart from the 1045 and 1100 slot no missing segments up to 2145.

Greetings,
Arne van Belle


Re: Missing segments

Robert Moore
 

David - these, and some more, missing here.
Robert


Quoting David Taylor <david-taylor@...>:

Did anyone else just get gaps in the 1100 cycle, or do I have a
local defect?

Missing HRIT & LRIT segments report
Cycle: 1100
msg-ch03, seg: 6
msg-ch05, seg: 6
msg-ch07, seg: 6
msg-ch12, seg: 18 19

I also got a gap in the 1045 LRIT cycle which wasn't reported as a
missing segment (ch 3 seg 2), and may have therefore been one with
bad data.

Thanks,
David



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------------------------------
Professor Robert Moore
Department of Sociology, Social Policy
and Social Work Studies
The University of Liverpool
Eleanor Rathbone Building
Bedford Street South
Liverpool
L69 7ZA

tel and fax: 44 (0) 1352 714456


Re: Missing segments

Douglas Deans <douglas@...>
 

----- Original Message -----
From: "David Taylor" <david-taylor@...>
To: <MSG-1@...>
Sent: Wednesday, November 19, 2003 11:24 AM
Subject: [MSG-1] Missing segments


Did anyone else just get gaps in the 1100 cycle, or do I have a
local defect?

Missing HRIT & LRIT segments report
Cycle: 1100
msg-ch03, seg: 6
msg-ch05, seg: 6
msg-ch07, seg: 6
msg-ch12, seg: 18 19

I also got a gap in the 1045 LRIT cycle which wasn't reported as a
missing segment (ch 3 seg 2), and may have therefore been one with
bad data.

Thanks,
David


My report is exactly the same, David, except my 10.45 also shows HRIT
channel 9 segment 6 missing. (and it is ).

Regards
Douglas.


Re: Missing segments

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

Also missing here David but 1045 LRIT OK.

Peter
Thanks, Peter and John. I thought my gremlin had crept back into
the LNB again!

Cheers,
David


Re: Missing segments

John Thexton <john@...>
 

Yes same here David but all reported as missing segments.

John

----- Original Message -----
From: David Taylor
To: MSG-1@...
Sent: Wednesday, November 19, 2003 11:24 AM
Subject: [MSG-1] Missing segments


Did anyone else just get gaps in the 1100 cycle, or do I have a
local defect?

Missing HRIT & LRIT segments report
Cycle: 1100
msg-ch03, seg: 6
msg-ch05, seg: 6
msg-ch07, seg: 6
msg-ch12, seg: 18 19

I also got a gap in the 1045 LRIT cycle which wasn't reported as a
missing segment (ch 3 seg 2), and may have therefore been one with
bad data.

Thanks,
David


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Re: Missing segments

Peter Benney <tugboat@...>
 

Did anyone else just get gaps in the 1100 cycle, or do I have a
local defect?

Missing HRIT & LRIT segments report
Cycle: 1100
msg-ch03, seg: 6
msg-ch05, seg: 6
msg-ch07, seg: 6
msg-ch12, seg: 18 19
Also missing here David but 1045 LRIT OK.

Peter