profcheck

From 094535c010320967639e8e86f974d878e80baa72 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rg=20Frings-F=C3=BCrst?= Date: Fri, 1 May 2015 16:13:57 +0200 Subject: Imported Upstream version 1.7.0 --- doc/profcheck.html | 285 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 165 insertions(+), 120 deletions(-) (limited to 'doc/profcheck.html') diff --git a/doc/profcheck.html b/doc/profcheck.html index ef0bc5b..a85e07e 100644 --- a/doc/profcheck.html +++ b/doc/profcheck.html @@ -3,7 +3,7 @@ profcheck + charset=windows-1252"> @@ -11,22 +11,25 @@

Summary

Check an ICC profile against .ti3 test chart - data.
+ data, and optionally create a pruned .ti3 file.

Usage Summary

profcheck - [-options] - data.ti3 iccprofile.icm
- - -v - [level]      - Verbosity level (default 1), 2 to print each DE
-c              Show + + + + + CIE94 delta E values
-k           @@ -35,157 +38,204 @@ Show -w              create - VRML visualization (iccprofile.wrl)

-x              Use - VRML axes
+ + + + + + X3DOM axes
-m              Make -VRML +X3DOM + + + + + lines a minimum of 0.5
-e              Color vectors - acording to delta E
- -d + + + + + + acording to delta E
+ -s              + Sort output by delta E
+ -h              + + + + + Plot a histogram of delta E's
+ -P + de           + Create a pruned .ti3 with points less or equal to de delta E
+ -d devval1,deval2,devvalN
                 Specify - a device value to sort - against
+ + + + + + a device value to sort against
-p              Sort + + + + + device value by PCS/Lab target
- - -f + -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:
+ observ       Choose CIE Observer for + spectral data:
                   - 1931_2 - (def.), - 1964_10, S&B - 1955_2, shaw, J&V 1978_2
+ + + + + + 1931_2 (def.), 1964_10, S&B 1955_2, shaw, + J&V 1978_2
-I intent       r = relative colorimetric, a = absolute (default)
data.ti3     -    - Test - point data file
+    Test point data file
iccprofile.icm Profile to check

Usage Details and Discussion

profcheck provides a way of checking how well an ICC 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 (colprof), 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.
+ 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 (colprof), + 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.

The -v flag prints out extra information during the - checking. A - value greater than 1 will print the color values of each test point.
+ checking. A value greater than 1 will print the color values of each + test point.

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.
+ 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 -w creates a VRML - 3D - visualization - of the differences between the test points and the profiles - prediction - of - the resulting colors.
-
- The -x flag adds Lab axes to the VRML output.
+ 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 -w creates a X3DOM + 3D visualization of the delta E's between the test points and the + profiles prediction of the resulting colors.
+
+ The -x flag adds Lab axes to the X3DOM output.

The -m 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.
+ view the distribution of test points in the reference set.

The -e flag causes the - error - vectors in the VRML output to be color coded according to their - lengths, from longest to shortest: yellow, red, magenta, blue, cyan - and - green.
+ 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.
+
+ The -s 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.
+
+ The -h flag will display a histogram plot of the fit delta + E's. The X scale is delta E, the Y scale is %
+
+ The -P N.NN 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. Note 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.
+
+ NOTE that the pruning does not take any special care as to + what test points are pruned - it may prune important points such as + white and black points!

The -d 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.
+ 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.

If the -p flag is used in combination with the -d - parameters, - then the test point by test point output will be sorted by distance - in - PCS - (Lab) space rather than distance in device space.
+ parameters, then the test point by test point output will be sorted + by distance in PCS (Lab) space rather than distance in device space.

The -f flag enables Fluorescent Whitening Agent (FWA) compensation. This only works if spectral data is available and, the @@ -197,31 +247,27 @@ Sort 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 + href="colprof.html#f">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 + 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.
+ 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.
+ observer. The default.
1964_10 selects the standard CIE 1964 10 degree observer.
1955_2 selects the Stiles and Birch 1955 2 degree @@ -232,16 +278,15 @@ Sort observer

The same parameter value should be used as was used during the - creation - of the profile.
+ creation of the profile.

The -I parameter allows changing the intent used in looking up the ICC profile colors to relative colorimetric. This would not 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.
+ underline;">not 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.

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