In　actual　manufacturing　of　fine-pitch　spur　gears,multiple　equipment　on　a　single　production　line　usually　produce　multiple　gears　with　different　parameters　at　the　same　time.　So　far,it　is　not　possible　to　use　a　single　gear　measuring　instrument　to　simultaneously　and　fully　inspect　these　gears　with　different　parameters　on　the　production　line　in　real　time.　We　have　developed　a　gear　subpixel　edge　positioning　algorithm　based　on　Facet,a　gear　center　positioning　method　based　on　iterative　reweighted　least　squares,a　fast　positioning　method　for　the　intersection　of　circles　and　profiles,a　sine　function　fitting　tooth　number　method,and　a　profile　approximate　pressure　angle　measurement　method.　If　combined　with　appropriate　feeding　and　positioning　mechanisms,this　method　can　achieve　mixed　measurement　of　multiple　different　types　of　gears　without　the　need　for　clamping,and　has　high　measurement　efficiency　when　unknown　parameters　are　present.　It　can　measure　the　number　of　teeth,modulus,pressure　angle,tip　diameter,root　diameter,whole　depth　of　tooth,tooth　width,base　tangent　length,modification　coefficient,profile　deviation,and　geometric　error.　The　experiment　result　shows　that　the　repeatability　accuracy　of　this　method　for　measuring　spur　gears　with　modules　ranging　from　0.　5　to　1.　0　mm　is　4　μm.　This　method　has　important　application　prospects　in　the　flexible　production　line　of　fine-pitch　spur　gears.　©　2024　Chinese　Academy　of　Sciences.　All　rights　reserved.