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Scheimpflug-Mount Optics for 3D Measurement Applications
Opto Engineering S.r.l. Posted 03/29/2011
3D profiling and measurement of objects with complex structures or inclined planes is frequently requested in a variety of industrial applications. In common imaging applications the image plane and the object plane are parallel: this ensures that the entire field of view is sharply imaged. When imaging an object with a complex structure or when structured light is projected onto inclined surfaces, normal optics will maintain the focus only within a small area close to the centre of the field of view; the rest of the image will show relevant defocusing thus making a 3D measurement inaccurate.
For this reason, Opto Engineering has developed a unique family of lenses and structured light projectors, specifically designed to fit the most demanding 3D measurement and reconstruction applications.
The new product family (3D optics) feature 3D Bi-Telecentric lenses, 3D LED Pattern Projectors and 3D Macro Lenses, all of which integrate a high-precision tilting mechanism based on the well-known Scheimpflug criterion - a geometric rule describing how an object plane that is not parallel to the image plane can be imaged completely in focus.
3D Bi-telecentric lenses have been developed to meet extremely accurate 3D dimensional measurement systems, to achieve very good focus at wide tilt angles and yield incredibly low distortion images, thanks to their bi-telecentricity.
Tilting the light source pattern becomes therefore essential to ensure that patterned light is properly and homogeneously focused across the entire sample surface. A click-stop tilting mechanism following the Scheimpflug criterion is built-into the 3D LED Pattern Projectors to ensure that the focus doesn’t change at the projection center, when the pattern is tilted.
3D Macro lenses can be interfaced to any structured light source to build up extremely accurate 3D imaging systems offering a wide range of magnifications and view angles. Image sharpness is maintained even when the lens is tilted by a wide angle, since the Scheimpflug adjustment is pivoted around the detector plane.