AutoWindowLevelTest.py

volumesDir = r"c:\Users\andra\OneDrive\Projects\SlicerTesting4\20190523-AutoWWWL\volumes"
screenshotsDir = r"c:\Users\andra\OneDrive\Projects\SlicerTesting4\20190523-AutoWWWL\screenshots"

methods = [
    ["baseline", autoContrastSlicerDefault],
    ["hist-0.1-99.9", lambda fn: autoContrastVtkImageHistogramStatisticsDefault(fn, 0.1, 99.9, 0.00, 0.0)], # = itksnap
    ["hist-1.0-99.9", lambda fn: autoContrastVtkImageHistogramStatisticsDefault(fn, 1.0, 99.9, 0.10, 0.0)],
    ["hist-1.0-99.0-x0.10", lambda fn: autoContrastVtkImageHistogramStatisticsDefault(fn, 1.0, 99.0, 0.10, 0.10)],
    ["hist-1.0-99.0-x0.20", lambda fn: autoContrastVtkImageHistogramStatisticsDefault(fn, 1.0, 99.0, 0.10, 0.20)],
    ]

def autoContrastVtkImageHistogramStatisticsDefault(volNode, lowPercentile, highPercentile, lowExpansionFactor, highExpansionFactor):
    stats = vtk.vtkImageHistogramStatistics()
    stats.SetAutoRangePercentiles(lowPercentile, highPercentile)
    stats.SetAutoRangeExpansionFactors(lowExpansionFactor, highExpansionFactor)
    stats.SetInputConnection(volNode.GetImageDataConnection())
    stats.Update()
    displayNode = volNode.GetVolumeDisplayNode()
    displayNode.AutoWindowLevelOff()
    intensityRange = stats.GetAutoRange()
    displayNode.SetWindowLevelMinMax(intensityRange[0], intensityRange[1])

def autoContrastSlicerDefault(volNode):
    displayNode = volNode.GetDisplayNode()
    displayNode.AutoWindowLevelOn()

import os
screenCapture = slicer.modules.screencapture.widgetRepresentation().self().logic
screenCapture.showViewControllers(False)
for filename in os.listdir(volumesDir):
    print(filename)
    [success, volNode] = slicer.util.loadVolume(volumesDir+"/"+filename, returnNode=True)
    for (methodName, methodFunction) in methods:
        methodFunction(volNode)
        screenCapture.captureImageFromView(None, screenshotsDir+"/"+volNode.GetName()+"_"+methodName+".png")
    slicer.mrmlScene.Clear()

screenCapture.showViewControllers(True)

# Experiment with a specific volume:
#   volNode=slicer.mrmlScene.GetFirstNodeByClass("vtkMRMLScalarVolumeNode")
#   autoContrastVtkImageHistogramStatisticsDefault(volNode,1.0,99.9,0.1,0.1)