[vtkusers] How to adjust the grey level for Volume Rendering

[Shawn Waldon]

To increase brightness, you simply increase the brightness of the color you
are using.  (Increase the RGB components).  To increase contrast, you
should use a brighter value at one end of the color scale and a darker one
at the other.  However, due to the blending that happens with transparency,
volume rendering is going to lose a lot of the contrast unless you remove
the transparency.

You may want to switch to use HSV colors.  If you want to use greyscale,
set the saturation (S) component to 0, and then the brightness is
controlled by the value (V) component.

I hope this helps,

Shawn

Please reply to all (or at least vtkusers) so that others have the
opportunity to help too.


On Thu, Jun 6, 2013 at 9:42 AM, ljp19890525 <ljp19890525 at 163.com> wrote:

> **
>   I have set the RGB  components  of vtkColorTransferFunction  to be the
> same,So it looks like grey images. I want to enhance the
> brightness and contrast. So What should I do next?
> Thanks a lot!
>  ------------------------------
>  ljp19890525
>
>  *From:* Shawn Waldon <swaldon at cs.unc.edu>
> *Date:* 2013-06-06 21:29
> *To:* ljp19890525 <ljp19890525 at 163.com>
> *CC:* vtkusers at vtk.org
> *Subject:* Re: [vtkusers] How to adjust the grey level for Volume
> Rendering
>    Which of these do you mean by "grey range":
>
> The color map and translucency mapping?
>
> Then try looking at:
>
> http://www.cmake.org/Wiki/VTK/Examples/Cxx/VolumeRendering/SmartVolumeMapper
> http://www.vtk.org/doc/nightly/html/classvtkColorTransferFunction.html
>
> The background color:
> Use the setBackground()<http://www.vtk.org/doc/nightly/html/classvtkViewport.html#a85eaf3ee2b0e49423efbaa41de17112d>function on your vtkRenderer.
>
> I hope this helps,
> Shawn
>
>
> On Thu, Jun 6, 2013 at 9:14 AM, ljp19890525 <ljp19890525 at 163.com> wrote:
>
>> **
>>   Hi all,
>> I have  done the Volume Rendering,and How to adjust the
>> grey range  for my Volume Rendering?  What should I do next?
>> heartfelt gratefulness!
>> ------------------------------
>>  ljp19890525
>>
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