profile/colverify
    Summary
    Verify a color transform by comparing CIE measurement values from
    two test charts. The charts can be any suitably formatted CGATS or .ti3 format that contains
    corresponding XYZ, Lab or spectral values. The overall average and
    worst case delta E will be reported, as well as the worst 10% and
    best 90% of values.
    Usage Summary
    colverify  [-options] target.ti3 measured.ti3
         -v
        [n]          
        Verbose mode, n >= 2 print each value
         -n              
Normalise
        each files reading to white Y
         -N              
Normalise
        each files reading to white XYZ
         -m              
        Normalise each files reading to its white X+Y+Z
         -M              
        Normalise both files reading to mean white XYZ
         -D              
Use
        D50 100.0 as L*a*b* white reference
         -c          
 
          Show CIE94 delta E values
         -k          
            Show CIEDE2000 delta E values
         -h              
        Plot a histogram of delta E's
         -s          
            Sort patch value by error
         -w          
 
          create X3DOM vector visualisation (measured.x3d.html)
       -W
                   
          create X3DOM marker & vector visualisation
        (measured.x3d.html)
      -x          
 
          Use X3DOM axes
         -f
          [illum]       Use Fluorescent
          Whitening Agent compensation [opt. simulated inst. illum.:
                            
          M0, M1, M2, A, C, D50 (def.), D50M2, D65, F5, F8, F10 or
          file.sp]
           -i illum        
          Choose illuminant for computation of CIE XYZ from spectral
          data & FWA:
                            
          A, C, D50 (def.), D50M2, D65, F5, F8, F10 or file.sp
           -o observ        Choose
          CIE Observer for spectral data:
                          
          1931_2 (def.), 1964_10, S&B
          1955_2, shaw, J&V 1978_2
           -L profile.icm   Skip any first file out of
          profile gamut patches
           -X file.ccmx     Apply Colorimeter
          Correction Matrix to second file
          target.ti3      
        Target or reference patch data file
         measured.ti3     Measured or actual patch
        data file
    Usage Details and Discussion
     colverify provides a way of verifying how well a color
    transformation (such a proofing) performs.
    
    The -v flag prints out extra information during the
    checking, and prints each patch value, rather than just a summary.
    
    The -n flag causes the two sets of values to be normalized
    to the Y value of white for each set before comparison. White is
    assumed to be the patch with the largest Y value.
    
    The -N flag causes the two sets of values to be normalized
    to the XYZ of white for each set before comparison. White is assumed
    to be the patch with the largest Y value.
    
    The -m flag causes the two sets of values to be normalized
    to the X+Y+Z of white for each set before comparison. White is
    assumed to be the patch with the largest Y value.
    
    The -M flag causes the two sets of values to be normalized
    to the average XYZ of the whites from each set before comparison.
    White is assumed to be the patch with the largest Y value.
    
    The -D flag causes the white reference point for the
    conversion to L*a*b* to be D50 with a Y value of 100%. By default
    the sample with the largest Y value is found, and the L*a*b* white
    reference scaled to have that Y value. This allows sensible delta E
    values when comparing absolute color values, such as those from
    emission or display measurements.
    
    The -c option causes the differences between the test values
    and the profile prediction of the color for each device value to be
    displayed in CIE94 delta E, rather than plain L*a*b* delta E. CIE94
    delta E has a closer correspondence with perceived color differences
    than the default CIE76 delta E values.
    
    The -k option causes the differences between the test values
    and the profile prediction of the color for each device value to be
    displayed in CIEDE2000 delta E, rather than plain L*a*b* delta E.
    CIEDE2000 delta E has a closer correspondence with perceived color
    differences than either CIE76 or CIE94 delta E values.
    
    The -h flag will display a histogram plot of the fit delta
    E's. The X scale is delta E, the Y scale is %
    
    If the -s flag is used in combination with the -v
    flag, then the test point by test point output will be sorted from
    worst to best.
    
    The -w creates a X3DOM
    3D visualization of the differences between the test points in D50
    L*a*b* space, each difference being shown as a line vector. If the -W flag is used, then the target
    and measured values will also be marked by a small sphere. This can
    be used to visualize the placement of values in a .ti3 (or other
    CGATS file) by using the same file for both "target" and "measured"
    values.
    
    The -x flag adds Lab axes to the X3DOM output.
    
    The -f flag enables Fluorescent Whitening Agent (FWA)
    compensation. This only works if spectral data is available and, the
    instrument is not UV filtered.  FWA compensation adjusts the
    spectral samples so that they appear to have been measured using an
    illuminant that has a different level of Ultra Violet to the one the
    instrument actually used in the measurement. The optional
    illumination parameter allows specifying a standard or custom
    illumination spectrum to be used as the similated instrument
    illuminant, overriding the default D50 or CIE computation
    illuminant used for FWA (see -i below). See colprof -f for a fuller explanation. The
    same value should be used as was used during the creation of the
    profile.
    
    The -i flag allows specifying a standard or custom
    illumination spectrum, applied to the spectral test point values to
    compute CIE tristimulus values. A, D50, D50M2,
      D65, F5, F8, F10 are a selection of
    standard illuminant spectrums, with D50 being the default.
    If a filename is specified instead, it will be assumed to be an
    Argyll specific .sp spectrum
    file. If FWA compensation is used during measurement, this
    illuminant will be used by default as the simulated instrument
    illuminant. The same value should be used as was used during the
    creation of the profile.
    
    The -o flag allows specifying a tristimulus observer, and is
    used to compute PCS (Profile Connection Space) tristimulus values.
    The following choices are available:
      1931_2 selects the standard CIE 1931 2 degree
    observer. The default.
      1964_10 selects the standard CIE 1964 10 degree
    observer.
      1955_2 selects the Stiles and Birch 1955 2 degree
    observer
      1978_2 selects the Judd and Voss 1978 2 degree
    observer
      shaw selects the Shaw and Fairchild 1997 2 degree
    observer
    
    The same parameter value should be used as was used during the
    creation of the profile.
    
    The -L profile.icm parameter causes colverify to
    ignore any patches from the first file that are out of gamut
    according to the profile. This can be useful in evaluating accuracy
    without tainting it by impossible to reach colors.
    
    The -X file.ccmx option applies the given 3x3
    calibration matrix to the values from the second file before doing
    any verification. This can be useful in evaluating the effects of a
    calibration matrix on raw colorimeter values, against reference
    values measured using a spectrometer.
    
    If both CIE and spectral values are present in the input files, the
    CIE values will be used by default. Using the -i, -o or -f
    flag will force spectral values to be used. The the -i, -o or -f
    flags will apply to both the target and measured input files.