Abstract: A system and method detect a local change to a region of an object using digital fingerprints of the object acquired at a reference time and at a test time. The two digital fingerprints may be used to authenticate the object, a match density is calculated from a comparison of corresponding portions of the digital fingerprints and the match density is compared to a threshold so that when the match density is below the threshold, a region where a component on the object has been added, subtracted, repositioned, substituted, or altered is identified.

Abstract: The present disclosure teaches a method of utilizing image “match points” to measure and detect changes in a physical object. In some cases “degradation” or “wear and tear” of the physical object is assessed, while in other applications this disclosure is applicable to measuring intentional changes, such as changes made by additive or subtractive manufacturing processes, which may, for example, involve adding a layer or removing a layer by machining. A system may include a scanner, and a digital fingerprinting process, coupled to an object change computer server. The server is coupled to a datastore that stores class digital fingerprints, selected object digital fingerprints collected over time, match measurements, and deterioration metrics.