how to compensate for low dynamic range monitors?

Hi all,

I have a bright image which is taken using good camera, and I upsampled it 
to a higher resolution(say NxN larger size)... and then applied some image 
processing, color space conversion, gamma transformation, inverse gamma, 
filtering, etc... and the new image look dark...(or equavalent, the LCD 
monitor does not support the new image due to its limited dynamic range... 
what can I do to compensate for the low dynamic range and still make the new 
one viewed from several meters a way the same as the old one?

Thanks a lot,

On 2004-11-29 09:18:51 +0100, "kiki" <lunaliu3@yahoo.com> said:

> Hi all,
> 
> I have a bright image which is taken using good camera, and I upsampled 
> it to a higher resolution(say NxN larger size)... and then applied some 
> image processing, color space conversion, gamma transformation, inverse 
> gamma, filtering, etc... and the new image look dark...(or equavalent, 
> the LCD monitor does not support the new image due to its limited 
> dynamic range... what can I do to compensate for the low dynamic range 
> and still make the new one viewed from several meters a way the same as 
> the old one?
> 
> Thanks a lot,

Well, if you apply "some image processing" to it and want it to look 
"the same as the old one" the obvious way is to avoid whatever 
processing you are doing.

What am I missing?
-- 
Stephan M. Bernsee
http://www.dspdimension.com

kiki wrote:

> Hi all,
> 
> I have a bright image which is taken using good camera, and I upsampled it 
> to a higher resolution(say NxN larger size)... and then applied some image 
> processing, color space conversion, gamma transformation, inverse gamma, 
> filtering, etc... and the new image look dark...(or equavalent, the LCD 
> monitor does not support the new image due to its limited dynamic range... 
> what can I do to compensate for the low dynamic range and still make the new 
> one viewed from several meters a way the same as the old one?
> 
> Thanks a lot,

I can guess what you're doing because of what you've written in other
threads. I don't like to guess, mostly because I'm too likely to waste
time and cogitation by guessing wrong. If this is the same problem you
already provided details about in another thread, starting a new thread
won't get you new information or recruit new gurus to your cause.

Examine the image after each processing step to learn which one dims it.
Learn how to do gamma correction. (Google) Brightness is increased by
adding a constant to each pixel. Be sure to make it color neutral.
Contrast is done by multiplying, but adjusting offset (brightness) is
often also needed.

You seem to be doing sophisticated transformations on images without
having enough of the ground concepts to guide you. Dig into that. Think
about the brightness and contrast controls on an old B&W TV.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������