Printer calibration adjusting NPac vector based on measurement data
地域：
TX
TX Spring
摘要
Certain examples described herein relate to printer calibration. In certain cases, measurement data is received, the measurement data indicative of an adjustment to be applied to a given colorant in a set of colorants printable by a printing system. In certain examples, a Neugebauer primary area coverage (NPac) vector comprising an area coverage of a first Neugebauer primary (NP) is obtained. Based on the received measurement data, the NPac vector is adjusted by decreasing the area coverage in the NPac vector of the first NP and increasing an area coverage in the NPac vector of a second NP. The first NP and the second NP correspond to colorant combinations that differ by a predetermined amount of the given colorant.
說明書
A printing system may include a plurality of different color printing fluids or colorants. By overprinting images for each of the printing fluids or colorants, an image with a range of different colors can be printed. An example printing pipeline may be calibrated so that printed colors are similar to or match desired colors, such as those defined in a digital format.
Various features of the present disclosure will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the present disclosure, and wherein:
權(quán)利要求
What is claimed is:1. A method of calibrating a printing system, the method comprising:receiving measurement data indicative of an adjustment to be applied to a given colorant in a set of colorants printable by the printing system; obtaining a Neugebauer Primary area coverage (NPac) vector comprising an area coverage of a first Neugebauer Primary (NP); and based on the received measurement data, adjusting the NPac vector by decreasing the area coverage in the NPac vector of the first NP and increasing an area coverage in the NPac vector of a second NP, wherein the first NP and the second NP correspond to colorant combinations that differ by a predetermined amount of the given colorant. 2. The method of claim 1 , wherein the colorant combinations corresponding to the first NP and the second NP each comprise a same amount of a further colorant in the set of colorants. 3. The method of claim 1 , wherein the predetermined amount comprises a minimum printable unit of the given colorant. 4. The method of claim 1 , wherein the colorant combination corresponding to the second NP comprises less of the given colorant than the colorant combination corresponding to the first NP. 5. The method of claim 1 , wherein the adjusting the NPac vector comprises decreasing the area coverage in the NPac vector of the first NP and increasing the area coverage in the NPac vector of the second NP by a same amount. 6. The method of claim 1 , comprising selecting the second NP from a matrix of NPs including the first NP and the second NP, the selecting being based on a position in the matrix of the first NP. 7. The method of claim 1 , comprising, in response to determining that an amount of the given colorant in the adjusted NPac vector has a predetermined relationship with the adjustment indicated by the received measurement data, further adjusting the adjusted NPac vector by decreasing the area coverage in the adjusted NPac vector of the second NP and increasing an area coverage in the adjusted NPac vector of a third NP,wherein the second NP and the third NP correspond to colorant combinations that differ by a further predetermined amount of the given colorant. 8. The method of claim 1 , wherein an initial area coverage in the NPac vector of the second NP is zero. 9. The method of claim 1 , wherein the adjusting the NPac vector comprises decreasing an area coverage in the NPac vector of a first further NP and increasing an area coverage in the NPac vector of a second further NP,wherein the first further NP and the second further NP correspond to colorant combinations that differ by a predetermined amount of the given colorant, and wherein the colorant combination corresponding to the first NP and the colorant combination corresponding to the first further NP each comprise a same amount of the given colorant. 10. The method of claim 9 , comprising decreasing the area coverage of the first NP using a first weighting and decreasing the area coverage of the first further NP using a second weighting, the first and the second weightings being based on an initial area coverage in the NPac vector of the first NP and the first further NP respectively. 11. The method of claim 1 , comprising using the adjusted NPac vector in a printing operation. 12. A printing system comprising:a printing device to print a calibration area onto a print substrate, the calibration area corresponding to a given colorant in a set of colorants printable by the printing system; a measurement interface to receive an indication of a measured optical property of the printed calibration area; a memory comprising a vector in an area coverage space, the vector defining a statistical distribution of colorant combinations including a first colorant combination over an area of a halftone; and a print controller to modify the vector on the basis of the measured optical property by decreasing a contribution to the vector of the first colorant combination and increasing a contribution to the vector of a second colorant combination, the second colorant combination differing from the first colorant combination by a predetermined amount of the given colorant. 13. The printing system of claim 12 , wherein the memory comprises a matrix of colorant combinations including the first colorant combination and the second colorant combination, the matrix being populated according to a predetermined format such that the second colorant combination may be identified on the basis of the position in the matrix of the first colorant combination. 14. The printing system of claim 13 , wherein different rows of the matrix comprise colorant combinations having different amounts of the given colorant. 15. A non-transitory computer-readable storage medium comprising a set of computer-readable instructions that, when executed by a processor of a printing system, cause the processor to:receive measured optical data indicating a measured optical property of a printed test area formed from a given printing fluid in a set of printing fluids useable by the printing system; and calibrate the printing system by modifying, based on the optical property of the printed test area, a Neugebauer Primary area coverage (NPac) vector, wherein the modifying the NPac vector comprises:decreasing an area coverage in the NPac vector of a first Neugebauer Primary (NP); and increasing an area coverage in the NPac vector of a second NP, wherein the first NP and the second NP each comprise a contribution of a printing fluid in the set of printing fluids, and wherein the first NP and the second NP comprise different contributions of the given printing fluid.
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