System and method for characterizing a printing device
A method is provided for constructing a look up table for characterizing a printing device, and a system therefore, wherein the look up table is an inverse look up table for obtaining for the printing device colorant values in a colorant space as a function of given color values in a color space. The method includes: (a) selecting an axis in the color space; (b) selecting a path in the color space; (c) determining color separation values in the colorant space for a plurality of points on the path; (d) analyzing the color separation values for a specific colorant; (e) determining a particular point on the path based on the analysis; (f) projecting the particular point on the axis, thus obtaining a projected point; and (f) adding the projected point to the look up table as a sampling point.
1 . A method for constructing a look up table for characterizing a printing device, wherein said look up table is an inverse look up table for obtaining for said printing device colorant values in a colorant space as a function of given color values in a color space, the method comprising the steps of:
selecting an axis in said color space;
selecting a path in said color space;
determining color separation values in said colorant space for a plurality of points on said path;
analyzing said color separation values for a specific colorant;
determining a particular point on said path based on said analysis;
projecting said particular point on said axis, thus obtaining a projected point; and
adding said projected point to said look up table as a sampling point.
2 . The method according to claim 1 further comprising the step of:
determining by said analysis of said color separation values a local extremum of said color separation values for said specific colorant.
3 . The method according to claim 1 further comprising the step of:
determining by said analysis of said color separation values a slope discontinuity of said color separation values for said specific colorant.
4 . The method according to claim 3 wherein said slope discontinuity is an ink changing point of said printing device.
5 . The method according to claim 3 wherein said slope discontinuity is a printer model boundary point of said printing device.
6 . The method according to any claim 1 wherein said path corresponds to a neutral color in said color space.
7 . The method according to claim 1 wherein said color space is CIELAB and said axis is CIE L*.
8 . The method according to claim 1 wherein said path coincides with said axis.
9 . The method according to claim 1 further comprising the steps of:
projecting said particular point on a second axis, thus obtaining a second projected point; and
adding said second projected point to said look up table as a another sampling point.
10 . The method according to claim 9 wherein said second axis is selected from the group consisting of CIE a* and CIE b*.
11 . The method according to any one of the claim 1 further comprising the step of:
adding all ink changing points of said printing device to said look up table as sampling points.
12 . The method according to claim 1 wherein said printing device is an ink jet printer.
13 . A system for constructing a look up table for characterizing a printing device, wherein said look up table is an inverse look up table for obtaining for said printing device colorant values in a colorant space as a function of given color values in a color space, the system comprising:
means for selecting an axis in said color space;
means for selecting a path in said color space;
means for determining color separation values in said colorant space for a plurality of points on said path;
means for analyzing said color separation values for a specific colorant;
means for determining a particular point on said path based on said analysis;
means for projecting said particular point on said axis, thus obtaining a projected point; and
means for adding said projected point to said look up table as a sampling point.
14 . The system according to claim 13 further comprising said printing device.
15 . A computer program for constructing a look up table for characterizing a printing device, wherein said look up table is an inverse look up table for obtaining for said printing device colorant values in a colorant space as a function of given color values in a color space, the computer program comprising code for performing the method of:
selecting an axis in said color space;
selecting a path in said color space;
determining color separation values in said colorant space for a plurality of points on said path;
analyzing said color separation values for a specific colorant;
determining a particular point on said path based on said analysis;
projecting said particular point on said axis, thus obtaining a projected point; and
adding said projected point to said look up table as a sampling point.
16 . A computer readable medium comprising program code adapted to carry out the method of:
selecting an axis in said color space;
selecting a path in said color space;
determining color separation values in said colorant space for a plurality of points on said path;
analyzing said color separation values for a specific colorant;
determining a particular point on said path based on said analysis;
projecting said particular point on said axis, thus obtaining a projected point; and
adding said projected point to said look up table as a sampling point.
17 . (canceled)