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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>profcheck</title>
<meta http-equiv="content-type" content="text/html;
charset=windows-1252">
<meta name="author" content="Graeme Gill">
</head>
<body>
<h2><b>profile/profcheck</b></h2>
<h3>Summary</h3>
Check an <a href="File_Formats.html#ICC">ICC</a> profile
against <a href="File_Formats.html#.ti3">.ti3</a> test chart
data, and optionally create a pruned .ti3 file.<br>
<h3>Usage Summary</h3>
<small><span style="font-family: monospace;">profcheck
[-options] data.ti3 iccprofile.icm</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"></span></small><small><span
style="font-family: monospace;">-v
[level] Verbosity level (default
1), 2 to print each DE</span></small><small><span
style="font-family: monospace;"></span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> -c
Show
CIE94 delta E values</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> -k
Show CIEDE2000 delta E values</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> -w
create
X3DOM visualization (iccprofile.x3d.html)</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> -x
Use
X3DOM axes<br>
-m
Make
X3DOM
lines a minimum of 0.5<br style="font-family: monospace;">
</span><span style="font-family: monospace;"> -e
Color
vectors
acording to delta E<br>
-s
Sort output by delta E<br>
-h
Plot a histogram of delta E's<br>
-P
de
Create a pruned .ti3 with points less or equal to de delta E<br
style="font-family: monospace;">
</span> <span style="font-family: monospace;"> -d
devval1,deval2,devvalN</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
Specify
a device value to sort against</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> -p
Sort
device value by PCS/Lab target</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">-f
[illum] Use Fluorescent Whitening
Agent compensation [opt. simulated inst. illum.:<br>
M0, M1, M2, A, C, D50 (def.), D50M2, D65, F5, F8, F10 or
file.sp]<br>
-i illum Choose
illuminant for computation of CIE XYZ from spectral data &
FWA:<br>
A, C, D50 (def.), D50M2, D65, F5, F8, F10 or file.sp</span><span
style="font-family: monospace;"></span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> -o
observ Choose CIE Observer for
spectral data:</span><br style="font-family: monospace;">
<span style="font-family: monospace;"></span></small><small><span
style="font-family: monospace;">
1931_2 </span></small><small><span style="font-family:
monospace;">(def.)</span></small><small><span
style="font-family: monospace;">, 1964_10, S&B 1955_2, shaw,
J&V 1978_2</span></small><small><span style="font-family:
monospace;"><br>
-I intent r = relative
colorimetric, a = absolute (default)<br style="font-family:
monospace;">
</span><i style="font-family: monospace;"> data.ti3</i><span
style="font-family: monospace;">
Test point data file</span><br style="font-family:
monospace;">
<i style="font-family: monospace;"> iccprofile.icm</i><span
style="font-family: monospace;"> Profile to check</span></small>
<br>
<h3>Usage Details and Discussion</h3>
<b> profcheck</b> provides a way of checking how well an <a
href="File_Formats.html#ICC">ICC</a> profile conforms to the test
sample data that was used to create it (or other test samples that
are from the same device). This is the same sort of check done
within the profile making tool (<a href="colprof.html">colprof</a>),
but having a separate tool provides some flexibility. The
absolute forward table in the profile is used to create PCS values
from the sample points, and the profiles PCS value then compared to
the PCS values of the measured sample points. Note the lower delta E
values are not always a better measure of how good a profile is. The
aim of a profile is to model the underlying characteristics of a
device, not to slavishly reproduce the sampled data point values.
Sampled data point values contain device variation and instrument
reading inaccuracies, and a good profiler will try and filter out
this noise, resulting in some deliberate differences between the
profile and the sample points used to create it.<br>
<br>
The <b>-v</b> flag prints out extra information during the
checking. A value greater than 1 will print the color values of each
test point on a line. The line consists of:<br>
<b>[</b><i>Delta_E</i><b>]</b><i> Patch_no</i><b>:</b><i>
Device values </i><b>-></b><i> Profile PCS values </i><b>should
be</b><i> .ti3 PCS values</i><br>
<br>
The <b>-c</b> 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.<br>
<br>
The <b>-k</b> 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.<br>
<br>
The <b>-w</b> creates a <a href="File_Formats.html#X3DOM">X3DOM</a>
3D visualization of the delta E's between the test points and the
profiles prediction of the resulting colors.<br>
<br>
The <b>-x</b> flag adds Lab axes to the X3DOM output.<br>
<br>
The <b>-m</b> flag makes each error line a minimum of 0.5 delta E
long, so that all the points are visible. This makes it easier to
view the distribution of test points in the reference set.<br>
<br>
The <span style="font-weight: bold;">-e</span> flag causes the
error vectors in the X3DOM output to be color coded according to
their lengths, from longest to shortest: yellow, red, magenta, blue,
cyan and green.<br>
<br>
The <b>-s</b> flag will cause the -v2 patch by patch delta E output
to be sort from largest to smallest. This is useful in identifying
badly read patches.<br>
<br>
The <b>-h</b> flag will display a histogram plot of the fit delta
E's, as well as print each bin's details. The X scale is delta E,
the Y scale is % area of each bin.<br>
<br>
The <b>-P N.NN</b> option will create a pruned .ti3 file called
data_pN.NN that contains just the measurement points that have a fit
delta E of less than or equal to the given delta E threshold. This
can be useful if you know that there are faulty or poor accuracy
readings in the data set. Use profcheck -h to examine the fit delta
E histogram to choose a threshold that cuts off the tail, and then
profcheck -P to create the pruned data set. You can check that this
is appropriate if a profcheck -h on the resulting profile no longer
has a long tail. <b>Note</b> that using this procedure will be of
no benefit if the tail is due to an inherently poor fit of the
profile to the data rather than reading innacuracy, even if it makes
the fit appear to be better.<br>
<br>
<b>NOTE</b> that the pruning does not take any special care as to
what test points are pruned - it may prune important points such as
<b>white</b> and <b>black</b> points!<br>
<br>
The <b>-d</b> parameters allow the specification of a particular
device value, and the test point by test point output will be sorted
by distance from the given device value. This can be useful in
determining how well "supported" the profile is in a particular area
of the colorspace.<br>
<br>
If the <b>-p </b>flag is used in combination with the <b>-d</b>
parameters, then the test point by test point output will be sorted
by distance in PCS (Lab) space rather than distance in device space.<br>
<br>
The <b>-f</b> 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 <b>D50</b> or CIE computation
illuminant used for FWA (see <b>-i</b> below<b>). </b>See <a
href="colprof.html#f">colprof -f</a> for a fuller explanation. The
same value should be used as was used during the creation of the
profile.<br>
<br>
The <b>-i</b> flag allows specifying a standard or custom
illumination spectrum, applied to the spectral test point values to
compute CIE tristimulus values. <b>A</b>, <b>D50</b>, <b>D50M2,
D65</b>, <b>F5</b>, <b>F8</b>, <b>F10</b> are a selection of
standard illuminant spectrums, with <b>D50</b> being the default.
If a filename is specified instead, it will be assumed to be an
Argyll specific <a href="File_Formats.html#.sp">.sp</a> 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.<br>
<br>
<a name="o"></a> The <b>-o</b> flag allows specifying a tristimulus
observer, and is used to compute PCS (Profile Connection Space)
tristimulus values. The following choices are available:<br>
<b> 1931_2</b> selects the standard CIE 1931 2 degree
observer. The default.<br>
<b>1964_10</b> selects the standard CIE 1964 10 degree
observer.<br>
<b>1955_2</b> selects the Stiles and Birch 1955 2 degree
observer<br>
<b>1978_2 </b>selects the Judd and Voss 1978 2 degree
observer<br>
<b>shaw</b> selects the Shaw and Fairchild 1997 2 degree
observer<br>
<br>
The same parameter value should be used as was used during the
creation of the profile.<br>
<br>
The <span style="font-weight: bold;">-I</span> parameter allows
changing the intent used in looking up the ICC profile colors to
relative colorimetric. This would <span style="text-decoration:
underline;">not</span> be used if you are checking a profile
against the .ti3 file that was used to create it, since, since
profiles are always made from absolute colorimetric measurement
values.<br>
<br>
<br>
<br>
<br>
<br>
</body>
</html>
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