The　coplanarity　of　BGA　(Ball　Grid　Array)　solder　balls　is　critical　for　reliable　connectivity　in　semi-conductor　units.　However,　existing　ball　height　inspection　techniques　require　high-cost　equipment　and　skilled　operators,　which　are　not　feasible　for　using　in　real-time　manufacturing　process.　In　this　paper,　a　fast　measurement　method　of　copla-narity　inspection　of　solder　balls　is　developed　based　on　structured　light　technique.　The　hardware　of　the　system　includes　a　camera　and　a　projector.　The　digital-light-processing　(DLP)　projector　emits　programmed　image　pat-terns　and　the　digital　complementary-metal-oxide-semiconductor　(CMOS)　camera　captures　distorted　image　pat-terns　on　solder　balls.　The　image　processing　software　is　developed　to　compare　the　original　and　distorted　image　patterns　to　reconstruct　the　three-dimensional　(3D)　solder　balls.　The　method　has　been　calibrated　extensively　and　exhibits　accuracy　within　5　mu　m　mean　squared　error　compared　to　ground　truth　values　determined　by　X-ray　computed　tomography.　The　proposed　method　achieves　reliable,　in-line　ball　height　measurement　and　could　be　potentially　used　for　real-time　in-line　coplanarity　inspection　of　BGA　chip　during　manufacturing.