Argyll - Things To Be Done (in no particular priority) -------------------------- Categories: 1) Active list 2) General 3) Documentation 4) Charts 5) Readings/Instruments 6) Profiles 6a) icclib 7) Linking, gamut mapping 7a) Profile/Link speedups 8) Raster conversion 9) Scanin 10) Bugs -------------------------------------------------------- 1) Active list: * Implement ICC V4 1a) Candidate list: * Get optimised separations working for CMY->CMYK & smoothed sep. option * Add monochrome suppport * Fix plot to have seperate thread etc, and add "save spectrum support" is spotread. * Fix xmatrix.c to allow for curve offset - this will improve quality of non-calibrated display matrix profiles greatly. 2) General: * Add full support for use as DLL/SO libraries * Check all executables & libraries with valgrind, and clean up leaks and unitialised memory. * Merge changes from Rhett Sutphin into iccdump that support dumping embeded profiles from known file formats. * Create a utility for converting color profiles to monochrome. ie. CMYK -> K only, RGB -> R=G=B profile. Have option for forcing the profile to be a color profile but monochrome output. Have an option for outputing a clut based or ICC monochrome profile. * Add support for ink-subset profiling, e.g. Monochrome like inks only (light + K etc.). For full support, would have to support gamut mapping of 2D colorspaces. * Add support for an Argyll private ICC tag, and use it to convey the device ink limit, and other profile creation information for improved linking checking and convenience. * Add support for a (private tag) real gamut clut as a 3D surface in profile. * Add > 4 color device optimised separations creation support. * Add optimised separations handling for CMYK profile generation option. * Switch to balltree acceleration for gamut and rspl rev code. * Switch to ball tree for targen spatial acceleration ?? * Re-code all of argyll to be a consistent set of APIs, to make it a full "library". Python interface ? * Fixup error and allocation code in all the Argyll libraries. Add a better error reporting mechanism ? * Create a useful system independent build system, and convert Argyll to use it (ie. based the "gin" version of jam ?). * Write utilities to convert ICC profiles into PostScript CSD and CRD's. * Define an open operating system color service API, and reate an example implementation with Argyll. * Add a central #define (or even run time flag/envronment param) to choose whether the default ICC extension is .icm or .icc. * Add extra information to gamut surface format (.gam) files to note color space the gamut and intent is represented in. This is to be able to detect (and possibly convert) incompatible gamuts. * Make printspot more flexible - load spectrums, compare them etc. - similar to Xrites DTP41 utility. * Create a device "linearity" measure utlity. Read in a CLUT profile and compute the first and second differences of the grid. Report grid res. scaled average & maximums ? (What about input and output curve effects ? - sample overall chacateristics ??) 3) Documentation: * Add page on viewing condition parameters and typical values, to link to from profile, icclink etc. * Add help in generating greyscale test charts into targen doco.(-f0 etc.) * Add comment about support for other color instruments (X-Rite . * Add review of different file formats (.ti?, .mpp etc.), and keep them current. (Partly done) * Add doco on intependent verification of profile accuracy. * Document icclib api (Do this with V4 release!) * Document cgatslib api * Add "advanced scenarios" section to Argyll, to explain custom lighting, FWA, proofing fine tuning, etc. 4) Charts: * Create a test chart specifically for establishing an ink limit ? * Should create a .ti2 template file for some standard charts, such as an IT8.7/3, ECI2002 random and non-random etc. Scanner recognition files too ?? * Add an option to targen, that allows generation of test points down the neutral axis (how does this work for CMYK, since there are many possible values ?? - use ppoint with 1D target and 2D device ??) - try enhancing current CIE94 effect ?? + other memory colors like skin tones etc. * Started work on tiffsamp.c, but not complete. Utility for creating representativ test points from sample device images. * Add raster output option for print chart generation, as well as PS (Need a simple but general raster rendering module. How to render text ?? see argyll/render) * Create tool workflow to allow creating a "worst case" verification chart based on the veronoi locations of a chart used to create the profile needing verifying. 5) Readings & Instruments: * Would be nice to sort out issues with disabling screensavers and monitor powersave for dispcal and dispread (mostly done). Windows screensaver disable seems to work, but need to check if a separate call is needed to disable powersave. X11 seems to be a mess, because XGetScreenSaver appears to be buggy on most Linux systems (?) There were no obvious pointers to how to do this for OSX on the Apple devloper site. * Add support for the Gretag EyeOne (How without using their library, and without an instrument ?) * In chartread, add RGB and Monochrome "generic" profiles, so that bad reading scan be recognised (??) * Create utility that translates between an XYZ only .ti3 and an estimated spectral .ti3, based on a spectral .mpp, to allow applying WFA compensation using non-spectral instruments. 6) Profiles: * Determine typical statistical distribution of errors in relation to Lab space, and use per sample point weightings to apply more uncertaintly specific smoothing factors. * Add option to use XYZ as PCS, and matrix in B2A table to improve efficiency of B2A conversion (hence acuracy). * Investigate why using a black ink limit slows inversion down so much, and see if the performance can be improved. Shift black ink limit to be a calibration function ?? * Add support in ICC profile for embedding the .ti3 CGATS data within the profile. Add support for extracting it again in profile. * Add a custom tag that can encode a spectral A2B profile, to support illunimant specification at link time ? * Add xicc support for creating monochrome profiles from raw data. * Add support for regenerating perceptual and saturation B2A tables in revfix. Rename utility ? * Can FWA compensation be improved in accuracy ? It seems to over estimate FWA effect at high density of inks. Is this due to scattering effects, asymetry in the filtering effects of the colorant, or due to errors in estimating the colorants filtering effects into the UV region ? * Modify rspl thin plate spines to have a "simplex" data interpolation mode, rather than its "n-linear" one, for better correspondence with how data is interpolated within the grid ? (Is this really worth it ?) * Add smoothing for K locus generation for transtion to ink limiting. Need to detect region near ink limit, and then generate non-limited and limited values, and then regenerate reverse value with blended K locus target. Probably not important since ink limiting region is often very dark, and optimised separations could be used as an alternative mechanism. * Add an option for input (and display ??) profiles to include both matrix and Lut tables by default. (What PCS should it use, XYZ for the matrix, or Lab for the best quality Lut ?? What other CMS need such things ?) * Modify the rspl simplex code (and possibly imdi code) to orient the simplexes in each cell to minimse the expected curvature error at the center of each cell. 6a) Icclib: * Re-architect icclib to allow for unknown datatypes, dynamic custom tags, and full ICC V4 support. * Add full spot color library support * Change iccdump of Luts to dump PCS values as well as normalised integer values (table entries and indexes ?) 7) Linking, gamut mapping: * Would be nice to be able to weigh L errors more in gamut clipping. Would have to introduce scaling factors in rspl values to fake this without changing the insides of RSPL. * Fix xicc library to handle matrix/shaper profile inversion correctly, when the target is out of gamut. Don't clip in device space, clip to nearest in CAM space ! (Fix after iccV4 changes ?) * Fix xicc library to do better clipping for inputs that are out of range of the core ICC lookup mechanisms. * Want to add a mode similar to Absolute Jab to absolute Jab, that scales the luminance white end only, so that the source white just fits within the destination gamut. This is for D50 ish source to a D65 type monitor, to avoid having the source white point being clipped. Current grey mapping won't work because it just mapps the Lmax/Lmins, rather than the Lmax just in gamut. Add glum flag to create this behaviour ? Would this also work to "trick" monitor displays into having a bigger gamut ? * Add flag to work with "preserve black" that forces K only input to map to pure K only output, to suite use on press re-targeting. How about creating a gamut mapping to do this for arbatrary colorants ? - Can use "weak default mapping" to help curve shape ? How to handle resulting gamut shape change ?? * Add proper support for a "filtering" mode of black generation, that smooths the black colorant target to take into account gamut boundary issues. ie. revisit auxsmth.c ? Use optimised separations mechansim instead ?? * Add support in icclink for linking with monochrome in and out profiles. Gamut mapping needs to have monochrome bypass of 3D mapping. 7a) Profile/Link speedups * Add adaptive sampling reverse interpolation mode, to speedup high res inverse tables. Look at approach Done Bone used in adaptively measuring samples. * Add option to increase reverse cache lookup size (could this be automated ? Will it really help ?) * Add support in icclink and profile, for multi-threading the reverse interpolation calculations. This will allow great speedups when more than one processor is available. Simplest approach is to have multiple instances of rspl, and partition the problem into separate spaces (not interleaved). Cache contents shouldn't duplicate then. Multi-threading within rspl/rev would be complicated, and may be slow due to contentions. 8) Raster conversion: * Add support in IMDI for an auxiliary "calibration" or "linearisation" table as a parameter to the setup. [Calibration creation should allow for arbitrary curve manipulation, such as limiting maximums (to replace max K function), and other arbitrary curves.] 9) Scanin * Add support for 3 or 4 fiducials to be defined in .cht, and option of supplying them as options, as a workaround to failure of automatic recognition. * Add check in scanin that prints warning message if patch variance is too high (probable faulty read). * Add spectral fix options to scanin code to allow compensation for scanner and media errors when using a scanner as a colorimeter. This means figuring out how it will work, as well as creating to tools to create the spectral fix data (or just add general tweak/abstract profile support ?). * Modify scanin reference .cht format to be more robust (ie. CGATS) 10) Bugs * filmtarg doesn't work any more with latest .ti1 data format. Need to fix it.
