| Re: Stretching MODIS data [message #79119] |
Thu, 02 February 2012 05:59  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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titan writes:
> The problem which remains is that if I apply your suggestion to all
> the images, the general difference in brightness remains.
To *all* of them!? What were you thinking? No, just to
the dark ones! ;-)
> Do you think that an histogram matching could be a good solution??
Maybe. It is easy enough to try:
http://www.idlcoyote.com/ip_tips/histomatch.html
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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| Re: Stretching MODIS data [message #79120 is a reply to message #79119] |
Thu, 02 February 2012 05:23  |
titan
Messages: 59
Registered: March 2006
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Member |
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On 31 Gen, 16:16, David Fanning <n...@idlcoyote.com> wrote:
> titan writes:
>> Thank you David! I will try to check if this is my case too. I'll keep
>> you informed!!
>> in the meanwhile have you any idea why is this happening only for
>> images belonging to winter season??
>
> No, that confuses me. :-)
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.idlcoyote.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
Hi David,
your suggestion was quite useful!!Now winter season images are
brighter.
The problem which remains is that if I apply your suggestion to all
the images, the general difference in brightness remains.
Do you think that an histogram matching could be a good solution??
thank you
Cheers,
titan
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| Re: Stretching MODIS data [message #79142 is a reply to message #79141] |
Tue, 31 January 2012 07:08 |
titan
Messages: 59
Registered: March 2006
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Member |
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On 31 Gen, 14:40, David Fanning <n...@idlcoyote.com> wrote:
> titan writes:
>> I'm trying to obtain an RGB image using MODIS data channel 01,02,06
>> (daytime) and channels 20, 21 and 32 (night time).
>
>> My code is working fine except for the stretching result in the sense
>> that for the images obtained using "daytime channels" are darker than
>> the ones obtained with the "nighttime channels" and this happens only
>> for images belonging to winter season.
>
> I'm not sure this applies to your problem, but I've
> found that I needed to apply differential scaling
> to "brighten" MODIS images up:
>
> http://www.idlcoyote.com/ip_tips/brightmodis.html
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.idlcoyote.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
Thank you David! I will try to check if this is my case too. I'll keep
you informed!!
in the meanwhile have you any idea why is this happening only for
images belonging to winter season??
cheers
titan
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| Re: Stretching MODIS data [message #79187 is a reply to message #79119] |
Mon, 06 February 2012 07:18 |
titan
Messages: 59
Registered: March 2006
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Member |
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On 2 Feb, 14:59, David Fanning <n...@idlcoyote.com> wrote:
> titan writes:
>> The problem which remains is that if I apply your suggestion to all
>> the images, the general difference in brightness remains.
>
> To *all* of them!? What were you thinking? No, just to
> the dark ones! ;-)
>
>> Do you think that an histogram matching could be a good solution??
>
> Maybe. It is easy enough to try:
>
> http://www.idlcoyote.com/ip_tips/histomatch.html
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.idlcoyote.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
Dear David,
I tried using the histomatch code and it is also quite useful and
somehow more powerful!! :)
Since I would like to have a standard reference color is there a way
to define an histogram of reference to which all the images can be
referred??
thanks a lot!!
cheers,
Titan
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