The invention relates to a method of authenticating a physical object using a helper data and a control value associated with a reference object, the method comprising: acquiring a metric data of the physical object, generating a first property set using a noise compensating mapping on input data derived from information comprising said helper data and metric data, establishing a sufficient match between said physical and reference object using said property set and control value. The method further comprising a step to generate a noise measure, the step comprising the following sub-steps: reconstructing the output of a noise robust mapping generated during the enrolment of the reference object using the noise compensating mapping, and generating the noise measure by calculating the difference between the input to the noise compensating mapping and the output of the noise robust mapping. Also provided are an apparatus and system configured to carry out the method.