How WW/WL and ColorTransferFunction influence the visilization of the image.

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1

I set both ww/wl and ColorTransferFunction for a image property. I find when I adjust the ww/wl by mouse the appearence of the image change. I want to know the underline math of WW/WL and the ColorTransferFunction. Thanks.

2

Hi Iris,

You can find some information about window leveling here:
https://radiopaedia.org/articles/windowing-ct

Regarding ColorTransferFunction, it is the same idea, you create a color mapping function that converts the image scalar values into an RGB color. To do so, you associate an RGB color to a given scalar value and the color transfer function does interpolation between the colors you added (i.e. AddRGBPoint)

Hth,
Julien.

3

Thanks for your answer. I understand the idea of the window level, window width and colorTransferFunction. I want to know the exact intensity map function. Does the WW/WL convert the image intensity into the range of [0,1] by clip((i-WL+0.5WW)/WW,0,1). Does the input of the colorTransferFunction is the WW/WL transfered intensity, i.e. the output of clip((i-WL+0.5WW)/WW,0,1).

4

what actor/mapper are you using ?

5

Just vtkImageResliceMapper and vtkImageSlice.