FIELD: physics.
SUBSTANCE: based on acoustic permeability characteristics, which reflect passage of ultrasound through the valuable document (12) at its different points (O; O'), an indicator of the state of the valuable document is determined, which depends on variability of acoustic permeability characteristics from one of said different points to the other and characterising the state of the valuable document (12) from its dilapidation, and using the given criterion for the indicator of the state of the valuable document (12), its state is determined, where dilapidation is defined as the state of the valuable document in which, as a result of circulation, the document has less hardness and/or elasticity compared to the state it is in just after manufacture.
EFFECT: high reliability of evaluating the state of valuable documents.
34 cl, 7 dwg
