1. A method for monitoring the condition of an object, comprising: obtaining reference data that indicates the normal operational state of the object; obtaining input pattern arrays, each input pattern array having a plurality of time-ordered input vectors, each input vector having input values representing a plurality of parameters indicating the current condition of the object; generating, by at least one processor, estimate values based on a calculation that uses an input pattern array and the reference data to determine a similarity measure between the input values and reference data; and comparing the estimate values to the corresponding input values so that resulting values from the comparison can be used to determine the condition of the object.