System and method for determining which of a plurality of visually indistinguishable objects have been marked with a covert indicator

A method of determining which of a plurality of objects has been marked with a covert indicator, the method comprising the steps of:

• providing each of a plurality of objects with a metallized surface;
• recording a covert holographic indicator in a portion of the metallized surface on at least one of the plurality of objects, the covert holographic indicator being exposed to view but not being visible to the unaided human eye except when illuminated with a coherent reference light with a predetermined wavelength;
• scanning the portions of the metallized surfaces of the plurality of objects with a coherent reference light of the predetermined wavelength to reconstruct the recorded covert holographic indicator;
• and
• evaluating whether the scanned portions include the recorded covert holographic indicator.

A system for identifying a first type of objects from among a plurality of the first and a second type of objects which are generally visually indistinguishable, the system comprising:

• means for recording a covert holographic indicator in a portion of a surface of each of first type of objects, said covert holographic indicator being exposed to view but not being visible to the unaided human eye except when illuminated with a coherent reference light with a predetermined wavelength;
• means for scanning the surfaces of the first and second objects with a coherent reference light of said predetermined wavelength to reconstruct the recorded said covert holographic indicator;
• and
• means for evaluating whether the scanned surfaces include said covert holographic indicator, the presence of said covert holographic indicator indicating that a one of the objects on which said covert holographic indicator is detected is one of the first type of objects.