Image-spherizing-based planeness detecting method for a micro-channel plate

et al. 2022

Photonics

Self Cite

The detection of three-dimensional displacement, caused by micro-nano scale deformation, is of great significance for the industrial production of glass or quartz optical fiber products. Considering the detection cost and practicability, an image spherizing-based three-dimensional displacement measurement method for a monocular microscopic imaging system (a microscope with a normal industrial camera) is proposed. Differential theory tells us that an arbitrary large-scale deformation can be approximatively considered as the sum of slope-shaped deformations. In this paper, an ordinary slope model is presented by the idea of image spherizing and differential theory, which reveals the mathematical relation between in-plane displacement and out-of-plane displacement in the deformed images captured by an optical microscope. After obtaining the in-plane displacement field, the out-of-plane displacement field can be extracted from the in-plane displacement field by the ordinary slope model, which indicates that the out-of-plane displacement information carried by the in-plane displacement is fully utilized. Simulation and application experiments are performed to demonstrate the effectiveness and all the absolute errors of the measurement by optical microscope with a magnification of 50× are less than 0.2 μm. Unlike conventional methods, the new method does not need a phase unwrapping process during detection and has many attractive characteristics such as low-cost, simple arrangements and good applicability. Because the measurement precision of this technique can meet the detection requirement, it has been applied to the industrial detection of glass or quartz optical fiber products.

Section: Image Spherizing Algorithm and Differential Theorymentioning

confidence: 99%

Section: Image Spherizing Algorithm and Differential Theorymentioning

confidence: 99%

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Image Spherizing-Based Three-Dimensional Displacement Measurement Technique for Microscope with Single Camera

Zhao

Li²,

et al. 2022

Photonics

Self Cite

“…Although it is micro-scale deformation, the properties and performance of OFM will be seriously affected. For instance, in a night vision photomultiplier tube, once the coupling gap between MCP and FOP increases by 0.1 mm, the resolution of the photomultiplier tube will decrease by more than 20% [4]. Therefore, it is necessary to detect and monitor the deformation of OFM in practice in order to ensure the performance of the device works well.…”

Section: Introductionmentioning

confidence: 99%

Correlation-Based Out-of-Plane Displacement Measurement for Optical Fiber Material

Zhao

et al. 2021

Photonics

Self Cite

Due to the monitoring requirement of optical fiber industrial production, an out-of-plane displacement measurement method is proposed. Firstly, the in-plane displacements between two consecutive images, captured through a microscope with a CCD camera, are estimated by the Digital Speckle Correlation Method (DSCM). Subsequently, the out-of-plane displacement of optical fiber material can be obtained by the wedge model. Finally, the effectiveness of the method is verified experimentally by comparing the measurement data of routine practice with its theoretical values. Simulation and experimental results indicate that the absolute errors and the relative errors of the measurement by the optical microscope with a magnification of 50× are less than ±0.2 μm and 5%, respectively. The new method only needs two images obtained by the microscopic imaging system with a single camera to accomplish the measurement, which can significantly reduce the measurement time and complexity of the arrangement. Further, the method needs neither frequency domain conversion nor phase unwrapping operation, therefore, it is especially suitable for dynamic out-of-plane displacement measurement. The proposed method has been applied to the industrial uniformity and micro–nano-scale deformation monitoring of optical fiber image transmission materials.

“…is phase map can be used to determine the correspondence between the projector image and the camera image of a single-camera or multicamera projector system [10]. To extract the phase information from these fringes, algorithms based on phase shifting, Fourier transform, windowed Fourier transform, and wavelet transform have been developed [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Measurement of In-Plane and Out-of-Plane Displacements Using Talbot Fringe Projection

International Journal of Optics

2020

The fringe projection technique has been widely used in optical measurements. In this paper, we demonstrate a scheme to measure the 3D displacement of a deformed sample using Talbot fringe projection. In this process, we designed a two-dimensional square Talbot hologram. In this approach, we used the basic principle of triangulation, and a computer-controlled liquid crystal spatial light modulator (LC-SLM) was placed in the optical path. The Talbot array hologram was displayed on the LC-SLM screen and projected onto the surface of a sample. Two patterns were recorded: one before and one after deformation. We simultaneously acquired the in-plane and out-of-plane displacements using the digital image correlation (DIC) method. This scheme is simple and easily implemented. Theoretical and experimental results are presented.