Surface　defect　detection　is　a　common　engineering　task,　and　traditional　human　visual　inspection　suffers　from　low　efficiency,　poor　resolution,　and　a　lack　of　traceable　data.　We　propose　a　surface-topography　detection　system　based　on　multicolor　latitudinal　and　longitudinal　light　sources.　By　activating　multicolor　latitudinal　and　multicolor　longitudinal　light　sources　at　the　same　position　but　at　different　times,　decoupling　and　highlighting　of　the　surface　gradient　magnitude　and　direction　in　the　hue　domain　of　the　target　surface　can　be　achieved.　We　used　a　hot-rolled　aluminum　sheet　as　a　target　and　calibrated　the　vision　system,　achieving　recovery　of　the　gradient　magnitude　and　direction,　which　provided　the　necessary　conditions　for　defect　data　analysis.　We　also　used　a　hot-rolled　aluminum　sheet　as　the　target　for　collecting　co-located　latitudinal　and　longitudinal　images.　In　these　images,　various　surface　defects　were　highlighted　relative　to　the　background,　with　good　differentiation　between　the　different　defects.　©　2024　Elsevier　Ltd