1. A computer implemented method for constructing a strong classifier, comprising a computer processor for performing steps of the method, comprising the steps of: selecting a plurality of weak classifiers; representing an output of each weak classifier by a posterior probability; associating each weak classifier with a confidence matrix; combining the weak classifiers to form a set of combinations of the weak classifiers, in which the combining is an approximate Bayesian combination, and in which an output λ of each weak classifier is a random variable {tilde over (ω)} taking integer values from 1 to K, the number of classes, and a probability distribution over values of a true class label ω is P λ (ω|{tilde over (ω)}), and the approximate Bayesian combination is P a ⁡ ( ω i | x ) = ∑ k = 1 K ⁢ w k ⁢ ∑ j = 1 J ⁢ P k ⁡ ( ω i | ω ~ j ) ⁢ P k ⁡ ( ω ~ j | x ) ︸ P k ⁡ ( ω i | x ) , ⁢ where P k ({tilde over (ω)}|x) is a prediction probability of the weak classifier, and w k is a weight of the classifier; boosting each combination of the weak classifiers to determine a weighted score for each combination of the weak classifiers; and selecting combinations of the weak classifiers having a weighted score greater than a predetermined threshold to form the strong classifier.