Windows Color SystemWindows Color System

Evolution in the Microsoft Color Evolution in the Microsoft Color

Management EcosystemManagement Ecosystem Michael Bourgoin Michael Bourgoin Program Manager for Microsoft Color Community & ScienceProgram Manager for Microsoft Color Community & Science

Windows Digital Document Platforms & Solutions GroupWindows Digital Document Platforms & Solutions Group

© 2005 Microsoft Corporation. All rights reserved.This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

This is a preliminary document and may be changed substantially prior to final commercial release of the software described herein.

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The Windows Color System The Windows Color System (WCS)(WCS)WCS with Kyuanos is a collaboration WCS with Kyuanos is a collaboration

between the Microsoft and Canon, between the Microsoft and Canon, including Canon Development including Canon Development AmericaAmerica

The Microsoft Color Team and Canon The Microsoft Color Team and Canon Development America worked Development America worked together to realize WCStogether to realize WCS

WCS, like ICM before it, is integrated WCS, like ICM before it, is integrated with core Windows system with core Windows system components - WCS requires Windows components - WCS requires Windows Vista™Vista™

WCS in Windows Vista™ isWCS in Windows Vista™ isA new color management paradigm and A new color management paradigm and infrastructureinfrastructure

A transparent, modular, color processing A transparent, modular, color processing pipeline that allows for easy color pipeline that allows for easy color troubleshootingtroubleshooting

A new development platform for advanced A new development platform for advanced color devices and applicationscolor devices and applications

A platform for innovation in color A platform for innovation in color managementmanagement

The first step in a staged implementation The first step in a staged implementation process that will span several Windows process that will span several Windows releasesreleases

NOT MANDATORYNOT MANDATORYIf it doesn’t make business sense in your If it doesn’t make business sense in your workflow, if it’s not better, don’t use it.workflow, if it’s not better, don’t use it.

WCS FeaturesWCS FeaturesContinued, improved support for ICC-based workflowsContinued, improved support for ICC-based workflowsNew explicitly staged color processing pipelineNew explicitly staged color processing pipelineNew, Simple XML Profile FormatsNew, Simple XML Profile Formats

Easy to edit, verify, understand and extend by third partiesEasy to edit, verify, understand and extend by third partiesNew Visual ModelNew Visual Model

CIECAM02 instead of reflection-print-like PCSCIECAM02 instead of reflection-print-like PCSBuilt-in baseline device models for common device classesBuilt-in baseline device models for common device classes

Extensible by third party plug-in device modelsExtensible by third party plug-in device modelsSelectable gamut mapping modelsSelectable gamut mapping models

Support for third party plug-in gamut mapping models for Support for third party plug-in gamut mapping models for proprietary algorithms or improvements on baseline gamut proprietary algorithms or improvements on baseline gamut mapping modelsmapping models

Transforms can support black preservationTransforms can support black preservationSupport for high dynamic range, wide gamut, high precision Support for high dynamic range, wide gamut, high precision color data (up to 32 bpc float)color data (up to 32 bpc float)

scRGB with a realistically defined gamut boundary (“wcsRGB”)scRGB with a realistically defined gamut boundary (“wcsRGB”)New centralized color control panelNew centralized color control panel

Per-user as well as system-wide profile/device associations, Per-user as well as system-wide profile/device associations, defaults, and settingsdefaults, and settingsNon-Admin users can now install/uninstall profilesNon-Admin users can now install/uninstall profiles

Windows Color System and Windows Color System and ICC workflowsICC workflows

WCS still supports and defaults to the same WCS still supports and defaults to the same sRGB ICC profile as previous Windows sRGB ICC profile as previous Windows versionsversionsSeamless interoperability with ICC profile-Seamless interoperability with ICC profile-based workflowsbased workflows

ICC-only transforms run through improved ICM3 ICC-only transforms run through improved ICM3 CMMCMMMixed ICC & WCS transforms run through WCS Mixed ICC & WCS transforms run through WCS CITECITE

Any existing code that uses ICM2 APIs will Any existing code that uses ICM2 APIs will continue to work without any change continue to work without any change requiredrequiredICC Version 4 support is added to ICMICC Version 4 support is added to ICMAddressing key recorded ICM bugsAddressing key recorded ICM bugsImplement new functionality via current Implement new functionality via current ICM2 APIsICM2 APIsOld applications work with new profilesOld applications work with new profilesNew profile format is processed by current New profile format is processed by current ICM2 APIsICM2 APIs

The Parts of the Windows Color The Parts of the Windows Color SystemSystem

New WCS XML-based color profile formatsNew WCS XML-based color profile formats

Color Infrastructure & Translation Engine Color Infrastructure & Translation Engine (CITE)(CITE)

The Color Appearance Model (CAM)The Color Appearance Model (CAM)Based on CIECAM02Based on CIECAM02

Gamut Boundary and Gamut Shell Gamut Boundary and Gamut Shell FunctionsFunctions

The Baseline Device Model SetThe Baseline Device Model SetExtensible via Device Model Plug-insExtensible via Device Model Plug-ins

The Baseline Gamut Map Model SetThe Baseline Gamut Map Model SetExtensible via Gamut Map Model Plug-insExtensible via Gamut Map Model Plug-ins

And of course the improved ICM CMM, with And of course the improved ICM CMM, with ICC version 4 profile support addedICC version 4 profile support added

WCS PipelineWCS Pipeline

GamutMap Model

C

DeviceModel A

ColorAppearance

Model

ColorAppearance

Model

DeviceModel B

Device Color Space

Device-Independent Color SpaceCIEXYZ

Color Appearance Space CIECAM02 JCh

DeviceModels

GamutMap

Models

Device Model Profile A

Device Model Profile B

Gamut MapModel C

Profile

CAMP forDevice BViewing

Conditions

CAMP forDevice AViewing

Conditions

Device A Device B

GBD A GBD B

WCS Profile FormatsWCS Profile FormatsEach type has its own schemaEach type has its own schema

Device Model Profile (DMP), file extension Device Model Profile (DMP), file extension “.cdmp”“.cdmp”

A DMP targets a particular device model, either one of A DMP targets a particular device model, either one of the built-in “baseline” device models, or a plug-in device the built-in “baseline” device models, or a plug-in device modelmodelDMPs targeting plug-in device models must also specify a DMPs targeting plug-in device models must also specify a baseline device model as a fallbackbaseline device model as a fallback

Color Appearance Model Profile (CAMP), Color Appearance Model Profile (CAMP), “.camp”“.camp”

A CAMP provides the parameters to the CIECAM02 A CAMP provides the parameters to the CIECAM02 equations for a specific viewing condition.equations for a specific viewing condition.

Gamut Map Model Profile (GMMP), Gamut Map Model Profile (GMMP), “.gmmp”“.gmmp”

A GMMP targets a particular gamut mapping model, A GMMP targets a particular gamut mapping model, either one of the built-in baseline gamut mapping either one of the built-in baseline gamut mapping models, or a plug-in gamut mapping model.models, or a plug-in gamut mapping model.As with DMPs, a GMMP that targets a plug-in GMM must As with DMPs, a GMMP that targets a plug-in GMM must also specify a baseline gamut mapping model as a also specify a baseline gamut mapping model as a fallback.fallback.

WCS profiles are embedded in image formats as a WCS profiles are embedded in image formats as a private tag in a WCS-created approximating ICC private tag in a WCS-created approximating ICC profileprofile

Necessary for interoperability off of Windows Vista™Necessary for interoperability off of Windows Vista™

A WCS sRGB profileA WCS sRGB profile

WCS Device ModelsWCS Device Models

WCS device models use the WCS device models use the measurement data from a DMP to measurement data from a DMP to instantiate a model that relates instantiate a model that relates device color space coordinates to device color space coordinates to CIEXYZCIEXYZ

Baseline device models implement Baseline device models implement different algorithms and processing different algorithms and processing models for different device classesmodels for different device classes

Third parties can extend the set of Third parties can extend the set of device models by writing plug-in device models by writing plug-in device modelsdevice models

WCS Baseline Device WCS Baseline Device ModelsModelsCRT Device ModelCRT Device Model

LCD Device ModelLCD Device Model

RGB Capture Device ModelRGB Capture Device Model

RGB Projector Device ModelRGB Projector Device Model

RGB Printer Device ModelRGB Printer Device Model

CMYK Printer Device ModelCMYK Printer Device Model

RGB Virtual Device ModelRGB Virtual Device ModelUsed for wcsRGBUsed for wcsRGB

ICC Virtual Device ModelICC Virtual Device ModelEnables use of ICC profiles in WCS Enables use of ICC profiles in WCS transformstransforms

Gamut Boundary Description Gamut Boundary Description & Gamut Shell Functions& Gamut Shell Functions

Internal to the WCS CITEInternal to the WCS CITE

The device gamut boundary function The device gamut boundary function takes the device model instantiated takes the device model instantiated for a DMP and the CAMP and derives for a DMP and the CAMP and derives a color device gamut boundary a color device gamut boundary description (GBD) as an indexed description (GBD) as an indexed vertex list of the hull of the device vertex list of the hull of the device gamut. gamut.

Depending on device model, GBDs Depending on device model, GBDs may consist of one to three nested may consist of one to three nested gamut shellsgamut shells

GBD ShellsGBD ShellsThese allow for different gamut These allow for different gamut mapping strategies in different mapping strategies in different regions of the device gamutregions of the device gamutReference Shell Reference Shell –– computed from the computed from the DMP measurement dataDMP measurement dataPlausible ShellPlausible Shell – generated using a – generated using a sampling of the color cube in device sampling of the color cube in device colorant space run through the DM, colorant space run through the DM, filtered for “real” colorsfiltered for “real” colorsPossible ShellPossible Shell – points for the possible – points for the possible shell for high dynamic range color shell for high dynamic range color spaces are generated using a spaces are generated using a sampling of the color cube in the HDR sampling of the color cube in the HDR space itself space itself

GBD ShellsGBD Shells

WCS Gamut Mapping Models WCS Gamut Mapping Models (GMMs) (GMMs)

All gamut mapping is performed All gamut mapping is performed between explicit source and between explicit source and destination GBD Shells in CIECAM02 destination GBD Shells in CIECAM02 JChJCh

WCS Baseline Gamut Mapping Models WCS Baseline Gamut Mapping Models correspond roughly to ICC rendering correspond roughly to ICC rendering intentsintents

Third parties can extend the set of Third parties can extend the set of available GMMs by writing gamut available GMMs by writing gamut mapping plug-insmapping plug-ins

WCS Baseline GMMsWCS Baseline GMMsSigmoidal Gaussian Cusp Knee Sigmoidal Gaussian Cusp Knee Clipping (SGCK)Clipping (SGCK)

Equivalent to ICC’s preferred, pictorial, or Equivalent to ICC’s preferred, pictorial, or perceptual intent. perceptual intent.

Minimum Color Difference (MinCD)Minimum Color Difference (MinCD)Equivalent to ICC colorimetric intents:Equivalent to ICC colorimetric intents:

Relative if neutral axis mapping is doneRelative if neutral axis mapping is done

Absolute without neutral axis mappingAbsolute without neutral axis mapping

HueMapHueMapEquivalent to ICC saturation or business Equivalent to ICC saturation or business graphics intentgraphics intent

Aligning the neutral axes in Aligning the neutral axes in CIECAM02 JChCIECAM02 JChFirst step in all WCS baseline GMMsFirst step in all WCS baseline GMMs

Chroma

Lig

htn

ess

Source Gamut Boundary

Lig

htn

ess

Chroma

Destination Gamut Boundary

Inverting the destination neutral Inverting the destination neutral axis alignmentaxis alignmentLast step in all WCS baseline GMMsLast step in all WCS baseline GMMs

Chroma

Ligh

tnes

s

MinCDMinCD

Chroma

Lig

htn

ess

B’

A’

Destination GBD

A chroma-dependent weight function is used for the distance in lightness so that the weight is smaller for small chroma and larger for large chroma until a threshold chroma is reached, after which the weight stays at 1, i.e. same weight as distance in chroma or hue.

SGCKSGCKBased on a combination of GCUSP (Morovic, 1998) Based on a combination of GCUSP (Morovic, 1998)

and the sigmoidal lightness mapping and cusp and the sigmoidal lightness mapping and cusp knee scaling proposed by Braun & Fairchild knee scaling proposed by Braun & Fairchild (1999)(1999)

Extended to handle multi-shell GBDsExtended to handle multi-shell GBDsSteps:Steps:1.1. Align neutral axesAlign neutral axes2.2. Apply lightness rescaling mapping to JApply lightness rescaling mapping to J

sigmoidal within the reference shell, and linear outsidesigmoidal within the reference shell, and linear outside

3.3. Compress J and C along lines towards the point Compress J and C along lines towards the point on the lightness axis having the same lightness on the lightness axis having the same lightness as the cusp of the destination gamutas the cusp of the destination gamut

compression function depends on shell intercept pointscompression function depends on shell intercept points

4.4. Apply a Minimum Color Difference clip to Apply a Minimum Color Difference clip to destination GBDdestination GBD

5.5. Invert destination GBD neutral axis alignmentInvert destination GBD neutral axis alignment

Lightness scaling for 2-shell Lightness scaling for 2-shell GBDGBD

SGCK – 2 shell caseSGCK – 2 shell case

reforefrrefrrefr

plarplao

refrrefo

gggg

gg

gg

,,,,

,,

,,

9.0 if9.09.0

00

Piecewise linear JC compression function:

HueMapHueMapThe first step is to determine the “Hue Wheels.” Find the JCh The first step is to determine the “Hue Wheels.” Find the JCh

values for primary and secondary colors for both source values for primary and secondary colors for both source and destination device. Here we are only considering the and destination device. Here we are only considering the hue components. hue components.

YY

G

C

B

M

R R

M

B

C

G

SourcePrimaries

&Secondaries

DestinationPrimaries

&Secondaries

Hue Angle ofDestination Color(40% from M to R)

Hue Angle ofInput Color

(40% from M to R)

HueMap HueMap (2)(2)

Second, we perform a lightness rescaling to map the Second, we perform a lightness rescaling to map the black/white points of the source leaf to the black/white points of the source leaf to the destination leaf, scaling all the J coordinates of the destination leaf, scaling all the J coordinates of the source boundary. The hue-mapped input color source boundary. The hue-mapped input color value is scaled in the same manner. value is scaled in the same manner.

Source White Point

Destination White Point

Destination Black Point

Source Black Point

J

CBefore Lightness

Rescaling

Hue Leaves

Source White Point

&Destination White

Point

Destination Black Point

&Source Black

Point

J

CAfter Lightness

Rescaling

Hue Leaves

Source BoundaryDestination Boundary

HueMap HueMap (3)(3)

Third, the cusp point of the source hue leaf is Third, the cusp point of the source hue leaf is linearly mapped to the cusp point of the linearly mapped to the cusp point of the destination hue leaf, using a “shear” destination hue leaf, using a “shear” operation that locks the J axis, keeping the operation that locks the J axis, keeping the black and white points stationary. Apply black and white points stationary. Apply this shear mapping to the lightness-this shear mapping to the lightness-adjusted, hue-rotated input color value.adjusted, hue-rotated input color value.

Finally perform MinCD clipping. Finally perform MinCD clipping.

Programming WCSProgramming WCS

Use existing ICM APIs and a few new Use existing ICM APIs and a few new WCS APIsWCS APIs

All are unmanaged APIsAll are unmanaged APIs

Open a Color ProfileOpen a Color Profile

ICC or DMP filename

OpenColorProfile()

Default Profiles in Registry

DMPfilename

CAMPfilename

GMMPfilename

WcsOpenColorProfile()

HPROFILE

CreateMultiProfileTransformCreateMultiProfileTransform

HTRANSFORM WINAPI CreateMultiProfileTransform(HTRANSFORM WINAPI CreateMultiProfileTransform(PHPROFILE PHPROFILE pahProfilespahProfiles, , // ptr to array of HPROFILEs// ptr to array of HPROFILEsDWORD nProfiles,DWORD nProfiles, // number of HPROFILEs (max 10)// number of HPROFILEs (max 10)PDWORDPDWORD padwIntentpadwIntent,, // ptr to array of intents// ptr to array of intentsDWORDDWORD nIntentsnIntents,, // number of intents (max 10)// number of intents (max 10)DWORD dwFlags,DWORD dwFlags, ////DWORD indexPreferredCMMDWORD indexPreferredCMM // ignored if any WCS profiles// ignored if any WCS profiles

););

pahProfilespahProfiles - profile array can contain a mix of ICC and WCS profile handles- profile array can contain a mix of ICC and WCS profile handlesIf only ICC profiles are used, processing will be via the improved ICM3 CMMIf only ICC profiles are used, processing will be via the improved ICM3 CMMnIntentsnIntents must equal 1, must equal 1, nProfilesnProfiles -1, or -1, or nProfilesnProfilesIntents corresponding to WCS HPROFILEs will result in the use of the corresponding Intents corresponding to WCS HPROFILEs will result in the use of the corresponding default GMMP mapped to that intent.default GMMP mapped to that intent.Intents specified in the Intents specified in the padwIntentpadwIntent array trump GMMPs in WCS HPROFILEs, unless… array trump GMMPs in WCS HPROFILEs, unless…For WCS profiles, setting the corresponding intent in For WCS profiles, setting the corresponding intent in padwIntentpadwIntent to to DWORD_MAXDWORD_MAX will will force use of GMMPs contained in WCS HPROFILEs (constructed with force use of GMMPs contained in WCS HPROFILEs (constructed with WcsOpenColorProfileWcsOpenColorProfile).).ICC DeviceLink, Abstract, and NamedColor profiles are not supported in combination ICC DeviceLink, Abstract, and NamedColor profiles are not supported in combination with WCS profileswith WCS profiles..

Transform Profile Sequence ExampleTransform Profile Sequence Example

INTENT_PECEPTUAL DWORD_MAX

HPROFILE A

DMPA

CAMPA

GMMPA

DMPB

CAMPB

GMMPB

DMPC

CAMPC

GMMPC

Default Profiles in Registry

DMPA +CAMPA

GBDA

DMPB +CAMPB

GBDBGMMPPercep. GMMPB

DMPC +CAMPC

GBDC

HPROFILE B HPROFILE C

padwIntent

New Central Color Control New Central Color Control PanelPanel

(UI still evolving)(UI still evolving)

Central Color Control PanelCentral Color Control Panel Associate Associate

Install/Uninstall Install/Uninstall Global Global SettingsSettings

TransparencyTransparency

We are publishing the internal design We are publishing the internal design specs for WCSspecs for WCS

Currently, all the WCS design Currently, all the WCS design documents are available under NDAdocuments are available under NDA

It is our intent to publish them on It is our intent to publish them on MSDN for non-NDA access prior to MSDN for non-NDA access prior to Windows Vista™ shippingWindows Vista™ shipping

In SummaryIn Summary

WSC supports existing color WSC supports existing color workflowsworkflows

WCS provides continuing, enhanced WCS provides continuing, enhanced ICC supportICC support

WCS supports “high, wide, & deep” WCS supports “high, wide, & deep” colorcolor

WCS implement state-of-the art color WCS implement state-of-the art color sciencescience

WCS represents a commitment by WCS represents a commitment by Microsoft to provide an extensible Microsoft to provide an extensible platform for color innovation that will platform for color innovation that will be viable for years to comebe viable for years to come

CommunityCommunity

Email questions/feedback to Email questions/feedback to mscolor @ microsoft.commscolor @ microsoft.com

WCS “Color at Microsoft” blog at WCS “Color at Microsoft” blog at http://blogs.msdn.com/color_bloghttp://blogs.msdn.com/color_blog

QuestionsQuestions

© 2005 Microsoft Corporation. All rights reserved.This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.