Patent ID: 7782489
Filing Date: 2010-08-24
Classification: H04N

Abstract:
1. A method for producing an optimal set of K number of samples useful in generating a transform for predicting a reflectance value producible by a printer, the printer having a predetermined number of colorants available to it, one of the colorants being a black colorant, each of the colorants being able to be characterized as a point CIE L*a*b* color space, the method including the steps of: a) operating a printer under a first target set of operating conditions to produce a collection of M number of samples, the collection including: b) operating a printer under a reference set of operating conditions to produce a collection of M number of samples, the collection including: c) measuring actual spectral reflectances for each sample in the provisional target subset, the remainder target subset, the first reference subset and the second reference subset; d) using the actual spectral reflectances measured for the samples in the provisional target subset and the first reference subset, creating a cross-validated, partial-least-squares transform that maps a reflectance from a sample produced under the reference set of operating conditions to a reflectance from a sample produced under the first target set of operating conditions; e) using the cross-validated, partial-least-squares transform and the actual reflectances measured from the amples contained in the second reference subset, generating a set of predicted reflectances for at least the samples in the remainder target subset; f) determining a difference ΔE in color space between pair-wise combinations of the predicted reflectances for samples in the remainder target subset and the measured reflectances for the samples in the remainder target subset, g) determining a criteria of acceptance A based upon predetermined descriptive statistics of the ΔE differences; h) based upon a comparison of the descriptive statistics of the ΔE differences and the criteria of acceptance A, iteratively creating an updated provisional target subset containing one or more of the samples from the remainder target subset together with the samples in the first provisional target subset, i) thereafter, performing steps c) through h) using the updated provisional target subset until descriptive statistics of the ΔE differences meet the criteria of acceptance A, provided that measurements in step c) are made for at least samples not previously measured; and j) operating a printer under a second target set of operating conditions to produce a collection of K number of samples, the collection being produced from the respective colorants or colorant combinations corresponding to the samples in the updated provisional target subset.