Achieving digital intraoral impressions is a key step in orthodontic, implant, and repair. Compared with the complex and time-consuming traditional plaster impression method, the intraoral 3D scanner can obtain digital impressions in real time. However, because of the saliva, enamel, metallic denture, etc., the quality of the captured 2D image, which is used for feature measurement and 3D reconstruction, is usually degraded.