Triangulation-based optical profilometry system

A triangulation-based optical profilometry system for scanning a three-dimensional sample surface located at a sample plane of the system, the system comprising:

• a projection system for projecting a luminous line across the sample surface, the luminous line extending laterally across the sample plane;
• an image sensor for converting images of the luminous line, as projected on the sample plane, into electrical signals, the image sensor being a two-dimensional array of pixels;
• a processing unit communicatively connected to the image sensor for processing the electrical signals;
• an objective lens assembly for imaging the luminous line, as projected on the sample plane, onto the image sensor, the objective lens assembly defining an optical axis extending between the sample plane and the image sensor,
• a lateral direction orthogonal to the optical axis and being defined parallel to an extent of the luminous line as projected, a vertical direction being defined perpendicular to the lateral direction, the lateral and vertical directions defining a plane orthogonal to the optical axis;
• and
• a diaphragm disposed along the optical axis between the sample plane and the image sensor, the diaphragm defining a non-circular aperture therein, the aperture being defined by a first dimension and a second dimension perpendicular to the first dimension, the second dimension being greater than the first dimension,
• the diaphragm being rotationally oriented relative to the image sensor such that the first dimension is aligned with the lateral direction and the second dimension is aligned with the vertical direction,
• the objective lens assembly being arranged to form an out-of-focus image of the sample plane on the image sensor,
• the diaphragm, the objective lens assembly, and the image sensor being arranged such that an image of a given point along the luminous line, as projected onto the sample surface and collected by the image sensor during operation of the system, exhibits greater vertical defocus than lateral defocus,
• during operation of the system, the image of the given point of the luminous line extending over a greater number of pixels of the image sensor in the vertical direction than in the lateral direction.