Digital holography three-directional shape detection device based on multi-wavelengths and multi-polarization states

Abstract

The invention discloses a digital holography three-directional shape detection device based on multi-wavelengths and multi-polarization states. The detection device comprises a laser light source, a light dividing and changing polarization state unit, a first light beam aligning unit, a to-be-detected object, a second light beam aligning unit, an optical length compensation and light beam deflecting unit and a CMOS camera. By combining the digital holography method and the multi-wavelength measuring technology, the detection device can be used for three-dimensional shape detection of an object whichis highly roughwith a non-optically smooth surface and an incontinuous and highly uneven surface structure. Based on effects on speckle distribution imposed by light wave polarization states, the detection device is capable of integrating information for multiple holograms in different polarization states, so effects on reconstructed images by speckles can be effectively restrained and signal to noise ratio can be increased.

Description

technical field [0001] The present invention relates to a three-dimensional shape detection system, more particularly, to a digital holographic three-dimensional shape detection system based on multi-wavelength and multi-polarization states. Background technique [0002] Digital holography technology uses CCD, CMOS and other photoelectric imaging detection devices as recording media, and records holograms in digital form, uses computer to digitally reproduce the optical diffraction process, reconstructs the three-dimensional light field, and obtains the amplitude and phase information of the light field at the same time . Its advantages include: (1) It is detected in a non-contact manner, which has little influence on the measured object; (2) The recording and reproduction process is completed in digital form, and the three-dimensional information of the object can be quantitatively analyzed; During the construction process, digital image processing technology can be conven...

AI Technical Summary

Problems solved by technology

[0003] In order to apply digital holography technology to the detection of three-dimensional shape of objects with high roughness or surface discontinuity, and obtain high-quality measurement results, some technical problems need to be solved: (1) The measurement range of digital holographic three-dimensional shape detection is only in the wavelength magnitude, and there is often a phenomenon of phase wrapping. For the discontinuous area on the surface of the object, the correct phase distribution cannot be obtained through the unwrapping operation, which limits the application range of this technology; (2) In the process of digital holographic detection, the recorded data It will contain speckle noise, which seriously affects the accuracy of the detection results, and will cause distortion of the reconstructed image and loss of details. Therefore, reducing speckle is of great significance to achieve high-precision 3D shape detection; (3) It is necessary to design the optical path reasonably , making the structure compact, high stability and easy to operate

Images