This　article　outlines　a　non-invasive　diagnostic　test　procedure,　whose　advantage　is　no　damage　to　the　artwork,　that　is　based　on　the　frequency　response　analysis　of　the　acoustic　excitation　of　the　wall　vibration.　The　detail　of　the　test　procedure　for　wall　vibration　and　the　system　of　the　measurement　instrument　is　described.　Experiments　were　performed　on　a　real　artificial　fresco　in　a　historic　vault.　A　two-dimensional　map　of　surface　vibration　amplitudes　is　generated　by　scanning　measurement　points　on　the　surface.　This　false-color　image　is　then　processed　through　image　analysis　techniques　to　determine　the　location　and　shape　of　the　damaged　area.　©　2021　ACM.