Four-step phase shift sine fringe field projection module based on liquid crystal negative film
A four-step phase shift, sinusoidal fringe technology, applied in the field of 3D measurement, can solve the problems of inconspicuous advantages of DFP projection, inconvenience in miniaturization of projection, and reduce equipment cost, and achieve the effect of mature and reliable production process, convenient control and low cost.
Active Publication Date: 2021-05-07
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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Problems solved by technology
Miniaturized 3D measurement based on phase-shifted sinusoidal fringes requires miniaturized sinusoidal fringe projection. The current widely used DFP projection technology uses high device costs and relatively complicated control, which is not conducive to reducing equipment costs. Equipment with a small overall size is not suitable, and in actual applications, the application scenarios are relatively fixed in many cases, and complex projection is not required, and the advantages of DFP projection are not obvious
In addition, the liquid crystal Ronchi grating method requires out-of-focus projection, and the method of mechanically moving the grating, the laser interference fringe method, and the existing various channel selection methods are not convenient for projection miniaturization
Method used
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[0017] The present invention will be further described below in conjunction with the examples.
[0018] This embodiment provides a four-step phase-shifted sinusoidal fringe projection module based on liquid crystal film, its structure is as follows figure 1 As shown, it includes: a backlight source 1, a liquid crystal negative film 2, a projection imaging lens 3, an expansion lens 4 and an electrode control circuit 5; wherein, the liquid crystal negative film includes an upper substrate and a lower substrate, and the upper substrate includes two COM electrodes: COM1 and COM2, the lower substrate includes two SEG electrodes: SEG1 and SEG2, and applying a driving voltage to these four electrodes can respectively display four sinusoidal binary filling patterns;
[0019] The ITO patterns of the upper substrate and the lower substrate adopt the same four-type division design, and the four-type division principles are as follows: figure 2As shown, it is divided by two sinusoidal w...
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The invention belongs to the technical field of 3D measurement, and provides a four-step phase shift sine fringe projection module based on a liquid crystal negative film, and the module is particularly suitable for being used in miniaturized 3D measurement equipment. The liquid crystal negative film is adopted and only comprises two COM electrodes and two SEG electrodes, driving voltage is applied to the electrodes to display sine-like binary filling patterns, and sine stripes are projected through a projection imaging lens and an extension lens; different power-up combination modes are selected, and the liquid crystal negative film can display four sine-like binary filling patterns meeting the four-step phase shift relation, therefore four sine fringe fields meeting the four-step phase shift are projected through time-sharing control. The projection module is simple in structure control and small in size, and is especially suitable for 3D measurement equipment requiring miniaturization of the overall size; meanwhile, based on simple structure and control and low-cost components, the projection module is easy to realize low cost.
Description
technical field [0001] The invention belongs to the technical field of 3D measurement, and mainly relates to a structured light 3D measurement technology using sinusoidal fringes, in particular to a four-step phase-shifting sinusoidal fringe field projection module based on a liquid crystal film. Background technique [0002] Structured light 3D measurement is a non-contact measurement. By projecting a specific structured light to the target to be measured, shooting the target with a camera, and then processing the captured picture, 3D measurement is realized; there are many types of projected structured light, among which the sinusoidal fringe light field It is one of the most commonly used structured light. The most important techniques for 3D measurement using sinusoidal fringe field include Fourier transform profilometry (FTP) and phase measurement profilometry (PMP), where FTP only needs one fringe to give As a result, when the target reflection pattern is complex and t...
Claims
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Login to View More IPC IPC(8): G02F1/1343G02F1/133G01B11/25
CPCG02F1/134309G02F1/13306G01B11/254G01B11/25
Inventor 彭仁军岳慧敏陈晓西刘旋田明睿杨立峰张靖
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA