Abstract: A method of learning a user query concept is provided which includes a sample selection stage and a feature reduction stage; during the sample selection stage, sample objects are selected from a query concept sample space bounded by a k-CNF and a k-DNF; the selected sample objects include feature sets that are no more than a prescribed amount different from a corresponding feature set defined by the k-CNF; during the feature reduction stage, individual features are removed from the k-CNF that are identified as differing from corresponding individual features of sample objects indicated by the user to be close to the user's query concept; also during the feature reduction stage, individual features are removed from the k-DNF that are identified as not differing from corresponding individual features of sample objects indicated by the user to be not close to the user's query concept.

Abstract: A method of measuring similarity of a first object represented by first set of feature values to a second object represented by a second set of feature values, comprising determining respective feature distance values between substantially all corresponding feature values of the first and second sets of feature values, selecting a subset of the determined feature distance values in which substantially all feature distance values that are selected to be within the subset are smaller in value than feature distance values that are not selected to be within the subset, and summing the feature distance values in the subset to produce a partial feature distance measure between the first and second objects.

Abstract: A method of learning user query concept for searching visual images encoded in computer readable storage media comprising: providing a multiplicity of sample images encoded in a computer readable medium; providing a multiplicity of sample expressions that correspond to sample images and in which terms of the sample expressions represent features of corresponding sample images; defining a user query concept sample space bounded by a boundary k-CNF expression and by a boundary k-DNF expression refining the user query concept sample space by, soliciting user feedback as to which of the multiple presented sample images are close to the user's query concept; removing from the boundary k-CNF expression disjunctive terms based upon the solicited user feedback; and removing from the boundary k-DNF expression respective conjunctive terms based upon the solicited user feedback.