Three-field of view digital holography detection device and method based on two-dimensional phase grating and point diffraction

Abstract

The invention provides a three-field of view digital holography detection device and a method based on a two-dimensional phase grating and point diffraction. The device comprises a light source (1) with an emergent wavelength to be lambda, a first polarizer (2), a collimating beam expansion device (3), a measurement window (4), a to-be-detected object (5), a first lens (6), the two-dimensional phase grating (7), a hole array (8), a second polarizer (9), a third polarizer (10), a fourth polarizer (11), a second lens (12), a diaphragm (13), an image sensor (14) and a computer (15). Field of view translation and frequency domain separation are realized through two-dimensional phase grating splitting and carrier introduction, interference of three object light beams can be avoided through the polarizer group, and reduction of crosstalk between spectra is realized. The method is simple and easy to operate, the adjustment is convenient, and the field of view use rate of the image sensor is high; a hologram carrier frequency mapping relation is simple, accurate control can be realized through grating defocus, the system carrier frequency determination complexity is low, and the phase recovery algorithm efficiency is high.

Description

technical field [0001] The invention belongs to the field of digital holographic detection, in particular to a three-field digital holographic detection device and method based on two-dimensional phase grating and point diffraction. Background technique [0002] On the basis of holography, digital holography uses CCD or CMOS as an image collector to replace holographic recording materials (holographic dry plate, etc.) The process realizes the reconstructed imaging of digital hologram. As a new type of three-dimensional digital imaging technology, digital holography involves digitization in its recording and reconstructing imaging processes. Among them, off-axis holography uses object light and reference light with a certain angle to interfere, and the phase information of the object to be measured can be obtained from the formed single carrier frequency interferogram, which is suitable for real-time measurement of moving objects or dynamic processes. [0003] In 2013, Shan...

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Problems solved by technology

But its structural alignment is more difficult

[0006] It can be found that the current multi-field digital holographic detection technology generally has shortcomings such as difficult collimation and low utilization of CCD field of view.

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