Large Aperture Interferometry System and Algorithm Based on 3D Stitching

Abstract

The invention discloses a large aperture interference measuring system and an algorithm based on three-dimension splicing, which adopts a Michelson interference system and is matched with an object lens and a camera possessing super-long working distance. The method comprising: utilizing a stepping motor to realize the automatic search of interference signals; realizing by piezoelectric ceramics the signal scanning; analyzing by a computer the acquired images and realizing measurement; after the completion of a single field-of-view measurement, controlling by a system the X-axis and the Y-axis working station to move; measuring the next field-of-view; and using the measurement results of the plurality of fields-of-view for three-dimension splicing algorithm to obtain the measurement result of a large aperture scope. In an original standard interference system, the switching mode between the monochromatic light and white light is used to realize the monochromatic light interference and the white light interference so that proper measurement scheme can be selected through the utilization of their advantages and disadvantages. At the same time, the adding of a two-dimension automatic moving platform at the detection sampling part realizes the free switching and real-time switching of tested areas.

Description

technical field [0001] The invention belongs to the field of high-precision three-dimensional shape measurement, and more specifically relates to an interference system suitable for large-scale surface shape measurement. Background technique [0002] Surface three-dimensional micro-topography measurement methods can be divided into two categories: contact and non-contact. The representative product of the contact measurement method is the stylus profiler. At present, the stylus type roughness measuring instrument widely used at home and abroad uses a stylus with a small tip radius to press on the surface to be tested for lateral scanning, and the stylus follows the shape of the surface microscopic contour for vertical displacement, which can be said to be The surface condition of the workpiece is reproduced to the greatest possible extent. However, this measurement method has great defects, such as low measurement accuracy, easy to scratch the measured surface, slow measur...

AI Technical Summary

Problems solved by technology

For all optical methods, the vertical resolution is high, but due to the limitation of diffraction limitation and the system's lateral resolution determined by the aperture of the objective lens, the lateral resolution can only reach the micron level, and the surface parameters evaluated by it are often the same as There are certain differences in the measurement results of other types of instruments

Secondly, the existing interference microscopy instruments are limited by the field of view of the optical system and the camera target surface when measuring surface topography, and the horizontal measurement range is very small, which cannot meet the measurement of large-diameter surface topography.

In addition, the operation of the high-precision 3D shape measurement system is relatively complicated, and the degree of automation is not high, requiring operators to have good professional skills

Images