Method and intraoral scanner for detecting the topography of the surface of a translucent object, in particular a dental object

A method for recording the topography of the surface (1) of a translucent, in particular dental, object (O) comprising the steps of:

• recording a first partial topography of a first partial area (B.I) of the surface (1) and a second partial topography of the second partial area (B.II) of the surface (1) overlapping at least partially the first partial area (B.I), wherein the recording of the partial areas (B.I, B.II) of the surface (1) is performed, respectively, by
• by projecting an overall measuring pattern of the respective partial area (B.I, B.II) of the surface (1) of the translucent object (O) by means of a projection system (11), wherein
• the projection system (11) includes at least one light source (30) and at least two diffractive optical elements (31),
• the overall measuring pattern comprises at least two different measuring patterns,
• the measuring patterns (6) are projectable onto the surface (1) and respectively comprise a plurality of measuring lines (9) parallel to each other,
• the measuring patterns (6) each have one of the diffractive optical elements (31) assigned to them, by means of which the measuring lines (9) can be generated through light diffraction,
• the at least one light source (30) illuminates the diffractive optical elements (31) with light linearly polarised in a polarisation direction (71), and a polarisation filter (70) is arranged between the surface (1) and the recording system (12), the direction of passage (72) of which coincides with the polarisation direction (71), and
• providing a first image and a second image of the respective partial area ((B.I, B.II)) of the surface (1) by means of a recording system (12), wherein in the first image a first of the at least two measuring patterns (6) is projected onto the respective partial area (B.I, B.II) of the surface (1) and in the second image a second of the at least two measuring patterns (6) is projected onto the respective partial area (B.I, B.II) of the surface (1), and
• recording the respective topography of the respective partial area (B.I, B.II) of the surface (1) respectively by means of triangulation using the respective first image and/or the respective second image,
• recording the topography of the surface (1) by at least partially superimposing the first partial topography and the second partial topography of the surface (1).