Casting and Intensity Mapping Filters


    This filter linearly rescales the pixel values, so that the minimum and maximum input values are mapped to minimum and maximum user-defined values. This is used to force the range of an image to fit a particular scale.

    Usage: itk-RescaleIntensityImage inputImageFile dimension outputImageFile minimum_value maximum_value
    Below is a set of sample output files, next to their parent input file. The minimum and maximum values are respectively: 0-50,50-100,100-150,150-255, with the following set of commands:
    itk-RescaleIntensityImage lafarge3col.tif rescale0-50.tif 2 0 50
    itk-RescaleIntensityImage lafarge3col.tif rescale50-100.tif 2 50 100
    itk-RescaleIntensityImage lafarge3col.tif rescale100-150.tif 2 100 150
    itk-RescaleIntensityImage lafarge3col.tif rescale150-255.tif 2 150 255

original data original data original data original data original data


    This filter applies a linear transformation to the intensities of the input image. This transformation is defined by 2 user input values:
    outputPixel = inputPixel*(scale_value) + shift_value;

    Usage: itk-ShiftScaleImage inputImageFile outputImageFile dimension scale_value shift_value
    Below is a series of filtered images where the shift is varied, using the following commands:
    itk-ShiftScaleImage lafarge3col.tif shift1.tif 2 50 1.1
    itk-ShiftScaleImage lafarge3col.tif shift2.tif 2 30 1.1
    itk-ShiftScaleImage lafarge3col.tif shift3.tif 2 -50 1.1

original data original data original data original data


    The linear transformation applied by this filter such that the statistical distribution of gray levels in the output image have zero mean and a variance of one:
    outputPixel = (inputPixel-mean)/sqrt(variance)

    Usage: itk-NormalizeImage inputImageFile outputImageFile dimension


    This filter maps a range of input pixel intensities to a different range, by making a smooth, continuous transition in the borders of the range. This is used mostly for focusing attention on a particular set of values. There are 4 different parameters to select the intensity range:
    OutputPixel_Intensity = (Max - Min)/(1 + exp(-(InputPixel_Intensity-Beta)/Alpha)) + Min
    Alpha defines the width of the intensity range. Beta defines the center of the intensity range.

    Usage: itk-SigmoidImage inputImageFile outputImageFile dimension sigmoidAlpha sigmoidBeta outputMinimum outputMaximum
    Below is a series of pictures of an image filtered with varying values of beta = 120,170,220, using the following commands:
    itk-SigmoidImage lafarge3col.tif sig170.tif 2 10 170 10 240
    itk-SigmoidImage lafarge3col.tif sig120.tif 2 10 120 10 240
    itk-SigmoidImage lafarge3col.tif sig220.tif 2 10 220 10 240

original data original data original data original data

Last updated November 18, 2005