[vtkusers] How to map negative grayscale to color?

[David Gobbi]

Hi Liu Peng,

You can set individual values in the lookup table,
in order to precisely map certain scalar values to
specific colors:

table->SetRange(-1024, 4095);
table->SetNumberOfTableValues(4095 + 1024 + 1);
for (int i = -1024; i < -10; i++) {
    table->SetTableValue(0.0, 0.0, 0.0, 1.0);
}
for (int i = -10; i <= 200; i++) {
    table->SetTableValue(0.0, 1.0, 0.0, 1.0);
}
etcetera.

 - David


On Mon, Mar 7, 2016 at 9:31 AM, Liu_tj <tjlp at netease.com> wrote:

> Hi,
>
> I try to use the vtkLookupTable to convert the grayscale to rgb color. The
> image scalar range is [-1024,3071] returned by
> vtkImageData::GetScalarRange(). Now I want to convert specific grayscale
> range, for example, [-10,200] to one color, such as green (RGB is 0,1,0).
> How to do that by vtkLookupTable? I have no idea what method should call:
> SetNumberOfTableValues(), SetRange(), SetHueRange(), SetValueRange(). What
> do "Hue" and "Value" stand for?
>
> BR,
> Liu Peng
>
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