Grating projection rapid non-contact measurement method and device for high-reflectance free-form curved-surface parts

Abstract

The invention relates to high-precision detection of complex optical curved-surface parts with large-curvature surface shapes, and aims to provide a high-precision detection method for the complex curved-surface parts with large curvature surface shapes, such as optical curved-surface parts, which has the advantages of rapidity, non-contact and no damage to part surfaces and surface layers. The technical scheme adopted by the invention is that the invention provides a grating projection rapid non-contact measurement method and device for high-reflectance free-form curved-surface parts, and the method comprises the following steps that: three degree-of-freedom motion of a measured object is realized with the help of a precision motion control system; coded grating fringes are projected onto the surface of the measured object by using a grating projection device; phase distribution information of the surface of the measured object is obtained from a deformed fringe pattern by using a digital phase shifting technology and a phase unwrapping algorithm; reference phase distribution information is obtained by using a virtual reference surface technology; and three-dimensional morphological information of a measuring area of the surface of the measured object is recovered according to a corresponding relation between phase deviation information and the gradient of the surface of the measured object. The grating projection rapid non-contact measurement method and device are mainly applied to the measurement of the optical curved-surface parts.

Description

technical field [0001] The invention relates to fast non-contact detection of high-reflection surfaces, in particular to a fast non-contact measurement method and device for grating projection on high-reflection free-form surfaces. Background technique [0002] Free-form surfaces refer to asymmetric, irregular, and unsuitable surfaces described by unified mathematical equations. Among them, free-form surfaces with high reflection characteristics, such as ultra-precision machining technology for optical free-form surfaces, are widely used in aerospace, national defense, biomedicine, and communications. , Microelectronics and other high-tech fields are more and more widely used, and have become key components in the optoelectronic and communication industries. A variety of application requirements also put forward higher requirements for the surface shape accuracy of highly reflective free-form surface parts. Accurate measurement and evaluation of the surface topography of hi...

AI Technical Summary

Problems solved by technology

However, in the current measurement methods, the corresponding relationship between the phase offset and the surface topography of the measured object is obtained based on the telecentric optical path model or through a complex measurement mechanism, and the acquisition of the phase offset information needs to be carried out on the measured object. Before measurement, first measure an actual reference plane to obtain the reference phase, and obtain the phase offset by subtracting it from the phase value of the corresponding point on the surface of the measured object, which increases the measurement complexity and reduces the measurement efficiency

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