| gamma correction [message #31261] |
Wed, 26 June 2002 01:14  |
carine castillon
Messages: 2
Registered: May 2002
|
Junior Member |
|
|
Hi all,
I have a question about gamma correction.
I'm displaying jpeg image, and I want to apply a gamma correction to this
image.
I don't know how to do. I'm trying gamma_ct procedure but there is no
effect.
Thanks for any help
Carine
PS : excuse me, but I don't speak english, I have some problems to write
this mail... :o(
|
|
|
|
| Re: gamma correction [message #31327 is a reply to message #31261] |
Wed, 03 July 2002 15:05  |
Dick Jackson
Messages: 347
Registered: August 1998
|
Senior Member |
|
|
"Craig Markwardt" <craigmnet@cow.physics.wisc.edu> wrote in message
news:onu1nncb6p.fsf@cow.physics.wisc.edu...
>
> David Fanning <david@dfanning.com> writes:
>
>> Craig Markwardt (craigmnet@cow.physics.wisc.edu) writes:
>>
>>> Beautiful rose, thank you very much! IDL versions checked from
>>> 5.2 to 5.4.
>>
>> That's what I thought. And that's why Dick's first solution
>> won't work for you. Those babies are not going through
>> the color tables. :-)
>
> Okay, now I guess I understand. Actually you fooled me, I thought the
> beautiful flower was the right answer. :-)
>
> Let me say that I think that the Windows/Mac approach, while it may be
> neato/keen, is just plain wrong. It's documented nowhere! The system
> documentation for DEVICE, DECOMPOSED=1 mentions nothing about such a
> transformation. There should be a documented flag to enable this, and
> then it should work consistently across platforms, darnit!
Having confirmed with Craig that this is the same behaviour on the X
device under True_Color=24 or Direct_Color=24 (which is different from
Windows), all I can say is "humph".
I think it's really a useful feature. If you can fiddle with a grayscale
image by just changing the colortable, why not have the same thing with
an RGB image? That's how it made sense to me when I discovered this
feature/bug, anyway.
Thanks for clearing this up, guys!
Cheers,
--
-Dick
Dick Jackson / dick@d-jackson.com
D-Jackson Software Consulting / http://www.d-jackson.com
Calgary, Alberta, Canada / +1-403-242-7398 / Fax: 241-7392
|
|
|
|
| Re: gamma correction [message #31355 is a reply to message #31261] |
Fri, 28 June 2002 16:46 |
Craig Markwardt
Messages: 1869
Registered: November 1996
|
Senior Member |
|
|
David Fanning <david@dfanning.com> writes:
> But then there would be no need for TVIMAGE, IMDISP, and... oh,
> what the heck was its name... PLOTIMAGE. It would be a less
> interesting world, to be sure. :-)
The interesting towns are still written up in the guide books.
:-)
Craig
--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
------------------------------------------------------------ --------------
|
|
|
|
| Re: gamma correction [message #31356 is a reply to message #31261] |
Fri, 28 June 2002 15:31 |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Craig Markwardt (craigmnet@cow.physics.wisc.edu) writes:
> Okay, now I guess I understand. Actually you fooled me, I thought the
> beautiful flower was the right answer. :-)
>
> Let me say that I think that the Windows/Mac approach, while it may be
> neato/keen, is just plain wrong. It's documented nowhere! The system
> documentation for DEVICE, DECOMPOSED=1 mentions nothing about such a
> transformation. There should be a documented flag to enable this, and
> then it should work consistently across platforms, darnit!
But then there would be no need for TVIMAGE, IMDISP, and... oh,
what the heck was its name... PLOTIMAGE. It would be a less
interesting world, to be sure. :-)
Cheers,
David
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
|
|
|
|
| Re: gamma correction [message #31357 is a reply to message #31261] |
Fri, 28 June 2002 15:04 |
Craig Markwardt
Messages: 1869
Registered: November 1996
|
Senior Member |
|
|
David Fanning <david@dfanning.com> writes:
> Craig Markwardt (craigmnet@cow.physics.wisc.edu) writes:
>
>> Beautiful rose, thank you very much! IDL versions checked from
>> 5.2 to 5.4.
>
> That's what I thought. And that's why Dick's first solution
> won't work for you. Those babies are not going through
> the color tables. :-)
Okay, now I guess I understand. Actually you fooled me, I thought the
beautiful flower was the right answer. :-)
Let me say that I think that the Windows/Mac approach, while it may be
neato/keen, is just plain wrong. It's documented nowhere! The system
documentation for DEVICE, DECOMPOSED=1 mentions nothing about such a
transformation. There should be a documented flag to enable this, and
then it should work consistently across platforms, darnit!
Craig
--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
------------------------------------------------------------ --------------
|
|
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
