Digital holographic interferometry and frequency-variable projection fringe compound measurement system and method

Abstract

The invention discloses a digital holography interference and variable frequency projection stripe duplex measurement system and method and belongs to the technical field of photoelectric measurement. The system comprises a set of continuous variable angle digital holography interference measuring device or a variable wave length digital holography interference measuring device and a set of multi-step variable frequency projection stripe measuring device. A multi-step variable frequency projection stripe measuring method is firstly used for roughly measuring an object to be measured so as to obtain a rough height range, and then the continuous variable angle digital holography interference measuring device or the variable wave length digital holography interference measuring device is used for precisely measuring the object to be measured so as to obtain the height information of all points of the object. According to the digital holography interference and frequency-changing projection stripe duplex measurement system and method, all the points of the object to be measured are measured independently in the measuring process, the phase unwrapping step is not needed, the surface type parameters of objects which are complex in shape and discontinuous can be measured, and compared with the unique multi-step variable frequency projection stripe measurement and the continuous variable angle digital holography interference or the variable wave length digital holography interference, the digital holography interference and frequency-changing projection stripe duplex measurement system and method have the advantage of being capable of meeting the requirement for high-precision measurement and the requirement for a large variation range of measuring heights at the same time.

Description

technical field [0001] The invention belongs to the technical field of photoelectric measurement, and in particular relates to a comprehensive measurement device and method combining continuously variable angle digital holographic interference (or variable wavelength digital holographic interference) and multi-step variable frequency projection fringe measurement. Background technique [0002] Digital holographic interferometry is a technology that uses laser interferometry for measurement. It has the advantages of non-contact, full-field measurement, high precision, high sensitivity, and quick and easy measurement. It can be used for flatness, coplanarity, and thickness. The measurement of parameters has broad application prospects in precision machinery, aerospace and other fields. [0003] In the existing digital holographic interferometry, the digital holographic information demodulation method is divided into two types. The first is the phase shift demodulation method, ...

AI Technical Summary

Problems solved by technology

Therefore, good unwrapping results cannot be obtained when the parcel map contains shadows, broken stripes, and discontinuous objects (with mutations).

However, most of the current projected fringe surface measurement methods require a phase unwrapping process, which makes it difficult for these methods to be applied to the measurement of objects with isolated and discontinuous regions, which are the most common in engineering

And its measurement accuracy is lower than that of holographic interferometry, but the measurement range is large

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