| Re: Problem displaying images on 8 bit monitor [message #50562 is a reply to message #50561] |
Tue, 10 October 2006 03:58   |
Jo Klein
Messages: 54
Registered: January 2006
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Member |
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Hi Mark,
This reminds me of colour allocation issues that were present in ancient
UNIX environments, where the number of colours allocated to IDL was
limited by a number of factors. I think Windows will reserve a number of
colours on an 8 bit device for its own purposes, such as window
decorations. Is there an option to increase the number of colours for
your graphics card? What are the contents of the !d variable? In
particular, !d.colors? What happens when you try to display a window
with window,colors=256? Do you run your monitor as a dual-head display,
or is it mirroring the contents of your primary monitor?
Just a few wild guesses,
Jo
mark wrote:
> Hi David,
>
> Here are how the images look. Both of these images are of the same
> variable:
> bytscl(bindgen(256) # bindgen(256))
>
> This first image is how it should look, and it does using other display
> programs on my monitor:
>
> http://hem.passagen.se/fysikern/idl/normal_display.tif
>
> This image is a screen-capture using TVRD() of the same variable
> displayed in IDL using either TV and TVSCL.
>
> http://hem.passagen.se/fysikern/idl/idl_display.tif
>
>
> The monitor I have is a CRT high-resolution mammography monitor (around
> 1500x2500 pixels)
>
> Any helpful hints?
>
>
> Mark
>
>
>
> mark skrev:
>
>
>> Hi David,
>>
>> Thanks for you responses yesterday but I still can't get the images
>> displayed properly. I'm sorry for insuating that IDL was at fault! :-)
>> I'm sure I'm not doing something right...
>>
>> In response to your suggestions yesterday:
>> TV, bindgen(256) # bindgen(256) yields a strange looking image (as
>> expected)
>>
>> TVSCL, bindgen(256) # bindgen(256) gives me an image of the type I've
>> been getting: a gradient consisting of narrow bands (or
>> tiles/contours). There are about 30 such distinct bands along the
>> gradient. I'm not sure if that number is significant. It would help if
>> I could send you a screen-dump or something to show you what I mean.
>>
>> TV, bytscl(bindgen(256) # bindgen(256)) gives the same result as above
>> with the bands.
>>
>> Byte scaling my own images doesn't change anything (they're already in
>> byte format).
>>
>> So I'm still in the same situation...
>>
>>
>> David Fanning skrev:
>>
>>
>>> mark writes:
>>>
>>>
>>>> So, there is something not set up right in my IDL environment...
>>>> and I have no idea what it is...
>>>
>>> I rather doubt this. :-)
>>>
>>> Can you humor me? Try these commands:
>>>
>>> IDL> Loadct, 0
>>>
>>> Is this what you are seeing:
>>>
>>> IDL> TV, bindgen(256) # bindgen(256)
>>>
>>> What about this?
>>>
>>> IDL> TVSCL, bindgen(256) # bindgen(256)
>>>
>>> What about if you scale your image before you display it:
>>>
>>> IDL> TV, BytScl(image)
>>>
>>> Cheers,
>>>
>>> David
>>> --
>>> David Fanning, Ph.D.
>>> Fanning Software Consulting, Inc.
>>> Coyote's Guide to IDL Programming: http://www.dfanning.com/
>>> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
>
>
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