In　order　to　solve　the　problems　of　weak　edges,　uneven　illumination,　and　non-uniform　bubble　distribution　in　floatation　surface　bubble　image,　we　propose　a　floatation　bubble　delineation　method　by　combining　nonsubsampled　Shearlet　transform　(NSST)　and　multiscale　boundary　detection　and　fusion.　First,　we　use　NSST　to　decompose　a　bubble　image　into　a　low-frequency　and　multiscale　multi-directional　high-frequency　subband　images.　Then,　we　use　adaptive　fractional　order　differential　valley　detection　templates　to　extract　valley　boundary　of　the　low-frequency　subband,　detect　the　edge　information　of　high-frequency　subband　images　based　on　scale　correlation　coefficient　and　direction　modulus　maximum,　and　extract　boundary　detail　from　the　edge　information　by　ridge　characteristics　determination.　Finally,　we　implement　bubble　delineation　through　multiscale　boundary　fusion　and　morphological　processing.　Experimental　results　show　that,　the　proposed　method　is　affected　little　by　noise　and　illumination,　and　can　effectively　delineate　bubbles　with　different　distribution　types.　The　average　detection　efficiency　and　accuracy　are　much　better　than　those　of　existing　methods.　This　method　meets　the　dynamic　changes　of　flotation　working　condition　well.　©　2018,　Chinese　Lasers　Press.　All　right　reserved.