RESUMEN
We study the accuracy of combined multiparameter measuring systems (CMPMSs) that determine several unknown quantities from measurements of a single variable at different preprogrammed conditions determined by control parameters. To reduce inaccuracies of determined quantities, we propose a mathematical method for selection of control parameters that are optimal for all possible values of determined quantities. Using the submultiplicativity of the spectral and Frobenius matrix norms, we construct the upper bound of the error function and determine the set of control parameters by minimizing this bound. To demonstrate the capability of our method for CMPMSs, we apply it to the polarized light microscopy technique called LC-PolScope, which is used for determining inhomogeneous two-dimensional fields of optical retardation and orientation of the slow optic axis in thin organic and inorganic samples. We compare the computed set of control parameters with other sets, including the one used in the PolScope, and demonstrate that our choice of control parameters works very well even though it does not take into account any specific features of the PolScope. We expect that our method will be successful in various CMPMSs, as it is applicable to any error distribution of the control parameters and measured values.