[Image-SIG] window level and width
fredrik at pythonware.com
Wed Jun 6 11:17:20 CEST 2007
Dr.Ashoka G K wrote:
> Many DICOM related softwares have a feature to alter window level and
> window width of the images. Is this the same as changing the
> brightness and contrast of the image?
my guess is that the "window" is the range of levels in the source image
that's being mapped to the 256 levels supported by most displays.
if "image" is an "L" or "I" image, you can use the "point" method to do
scale = 256.0 / window_width
offset = -window_level * scale
out = image.point(lambda i: i * scale + offset, "L")
to implement non-linear transforms, use a lookup table instead (see the
"point" documentation for details).
hope this helps!
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