Recent　advances　in　Lamb　wave-based　nondestructive　testing　technology　have　demonstrated　the　feasibility　of　detecting　and　locating　damages　in　structural　components.　However,　there　remains　many　challenges　to　realize　defect　detection　quantitatively　due　to　the　uncertainty　of　the　relationship　between　the　features　of　Lamb　waves　and　defect　size.　Therefore,　it　is　important　to　discover　an　intrinsical　parameter　of　Lamb　waves　that　can　be　used　as　a　damage　sensitive　feature.　Local　wall-thinning　is　a　common　defect　in　aluminium　plate-like　components　that　are　in　widespread　use　in　aerospace,　and　other　industries.　The　aim　of　this　paper　is　to　present　a　quantitative　defect　detection　method　for　achieving　damage　visualization　in　plate-like　structures　based　on　wave　propagation　phenomenon.　Full　wavefield　data　of　propagating　Lamb　waves　in　plates　contains　a　wealth　of　information　about　the　wave　interaction　with　damage　such　as　the　change　of　wavenumber　components.　The　wavenumber　of　excited　Lamb　wave　mode　is　a　fixed　value　for　a　given　frequency,　the　thickness　and　material　properties　of　the　plate.　When　Lamb　waves　propagate　to　the　structural　discontinuity,　new　wavenumber　components　are　created　by　abrupt　wave　changes.　To　estimate　spatially　dependent　wavenumber　values,　a　short　space　three-dimensional　Fourier　transform　(FT)　method　is　used　for　processing　wavefield　data.　The　method　utilizes　extracting　and　processing　of　full　wavefield　transceived　by　PZT-laser　detection　system　consisted　by　PZT　element　and　two-wave　mixing　interferometer.　A　local　wavenumber　analysis　method　is　presented　for　further　processing　full　wavefield　data　at　a　certain　frequency　to　estimate　spatially　dependent　wavenumber　values,　which　can　be　used　to　determine　thin-walled　thickness　and　shape.　Simulation　wavefield　data　are　obtained　by　ABAQUS　simulation.　Experimental　wavefield　data　are　obtained　by　PZT-laser　for　confirming　the　effectiveness　of　the　method.　Tests　performed　on　an　aluminium　plate　with　artificially　introduced　notch　to　confirm　the　effectiveness　of　the　method　and　its　potential　for　application　for　the　inspection　of　a　variety　of　structural　components.　©　2018　NDT.net.　All　rights　reserved.