3D information detection with novel five composite fringe patterns

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740088 ◽  
Author(s):  
Huaxia Deng ◽  
Ji Deng ◽  
Mengchao Ma ◽  
Jin Zhang ◽  
Liandong Yu ◽  
...  
Keyword(s):  
Relative Phase ◽  
Three Dimensional ◽  
Phase Shifting ◽  
Full Field ◽  
Full Field Measurement ◽  
Phase Map ◽  
Phase Shifting Method ◽  
Information Detection ◽  
Fringe Patterns ◽  
3D Information

A novel phase unwrapping method with five composite fringe patterns and phase-shifting method was proposed for three-dimensional information detection. The composite fringe patterns were composed of phase-shifted sinusoidal and stair phase-coding fringe patterns. The fringe patterns are five step phase-shifted. The relative phase and the stair code-words can be obtained simultaneously based on the five step phase-shifting algorithm. The monochrome composite structure has the improvement on the measurement speed and has the potential of solving the problem of color coupling and color imbalance. Combined with the modified minimum phase map theory, this method can provide more code-words for the full field measurement. Simulation and experimental results were presented in the final part to verify the flexibility and feasibility of the proposed method.

scholarly journals A Fringe Phase Extraction Method Based on Neural Network

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1664
Author(s):  
Wenxin Hu ◽  
Hong Miao ◽  
Keyu Yan ◽  
Yu Fu
Keyword(s):  
Neural Network ◽  
Fringe Pattern ◽  
Phase Shifting ◽  
Optical Metrology ◽  
Phase Extraction ◽  
Transform Method ◽  
The Neural Network ◽  
Phase Map ◽  
Phase Shifting Method ◽  
Fringe Patterns

In optical metrology, the output is usually in the form of a fringe pattern, from which a phase map can be generated and phase information can be converted into the desired parameters. This paper proposes an end-to-end method of fringe phase extraction based on the neural network. This method uses the U-net neural network to directly learn the correspondence between the gray level of a fringe pattern and the wrapped phase map, which is simpler than the exist deep learning methods. The results of simulation and experimental fringe patterns verify the accuracy and the robustness of this method. While it yields the same accuracy, the proposed method features easier operation and a simpler principle than the traditional phase-shifting method and has a faster speed than wavelet transform method.

3D Profile Variety Measurement of Pectoral Fin in Fish Fast Start

2011 ◽  
Vol 83 ◽  
pp. 280-284
Author(s):  
Ming Jiang ◽  
Shu Zhang ◽  
Xiao Yuan He
Keyword(s):  
Fourier Transform ◽  
High Speed ◽  
Kinetic Characteristic ◽  
Three Dimensional ◽  
Pectoral Fin ◽  
Fourier Transform Profilometry ◽  
Fast Start ◽  
Fringe Patterns ◽  
3D Information ◽  
3D Profile

Fast-starts are brief, sudden accelerations used by fish during predator-prey encounters. In this paper, a three-dimensional (3D) test and analysis method is critical to understand the function of the pectoral fin during maneuvers. An experiment method based on Fourier Transform Profilometry for 3D pectoral fin profile variety during fish maneuvers is proposed. This method was used in a carp fast-start during prey. Projecting the moiré fringes onto a carp pectoral fin it will produce the deformed fringe patterns contain 3D information. A high speed camera captures these time-sequence images. By Fourier transform, filter, inverse Fourier transform and unwrap these phase maps in 3D phase space, the complex pectoral fin profile variety were really reconstructed. The present study provides a new method to quantify the analysis of kinetic characteristic of the pectoral fin during maneuvers.

A New Three-Dimensional Profilometer for Surface Profile Measurement Using Digital Fringe Projection and Phase Shifting

2005 ◽  
Vol 295-296 ◽  
pp. 471-476
Author(s):  
Liang Chia Chen ◽  
S.H. Tsai ◽  
Kuang Chao Fan
Keyword(s):  
High Speed ◽  
Structured Light ◽  
Three Dimensional ◽  
Surface Profile ◽  
Phase Shifting ◽  
Fringe Projection ◽  
Surface Measurement ◽  
Profile Measurement ◽  
Digital Fringe Projection ◽  
Fringe Patterns

The development of a three-dimensional surface profilometer using digital fringe projection technology and phase-shifting principle is presented. Accurate and high-speed three-dimensional profile measurement plays a key role in determining the success of process automation and productivity. By integrating a digital micromirror device (DMD) with the developed system, exclusive advantages in projecting flexible and accurate structured-light patterns onto the object surface to be measured can be obtained. Furthermore, the developed system consists of a specially designed micro-projecting optical unit for generating flexibly optimal structured-light to accommodate requirements in terms of measurement range and resolution. Its wide angle image detection design also improves measurement resolution for detecting deformed fringe patterns. This resolves the problem in capturing effective deformed fringe patterns for phase shifting, especially when a coaxial optical layout of a stereomicroscope is employed. Experimental results verified that the maximum error was within a reasonable range of the measured depth. The developed system and the method can provide a useful and effective tool for 3D full field surface measurement ranging from µm up to cm scale.

scholarly journals A Calibration Method for System Parameters in Direct Phase Measuring Deflectometry

2019 ◽  
Vol 9 (7) ◽  
pp. 1444
Author(s):  
Xiaoting Deng ◽  
Nan Gao ◽  
Zonghua Zhang
Keyword(s):  
Liquid Crystal Display ◽  
Three Dimensional ◽  
Calibration Method ◽  
Concave Mirror ◽  
System Parameters ◽  
Dimensional Shape ◽  
Phase Map ◽  
Specular Objects ◽  
Fringe Patterns ◽  
Three Dimensional Shape

Phase measuring deflectometry has been widely studied as a way of obtaining the three-dimensional shape of specular objects. Recently, a new direct phase measuring deflectometry technique has been developed to measure the three-dimensional shape of specular objects that have discontinuous and/or isolated surfaces. However, accurate calibration of the system parameters is an important step in direct phase measuring deflectometry. This paper proposes a new calibration method that uses phase information to obtain the system parameters. Phase data are used to accurately calibrate the relative orientation of two liquid crystal display screens in a camera coordinate system, by generating and displaying horizontal and vertical sinusoidal fringe patterns on the two screens. The results of the experiments with an artificial specular step and a concave mirror showed that the proposed calibration method can build a highly accurate relationship between the absolute phase map and the depth data.

Fast two-step phase-shifting method for measuring the three-dimensional contour of objects

2021 ◽  
Vol 60 (09) ◽  
Author(s):  
Yang Chen ◽  
Baoan Song ◽  
Renji He ◽  
Hailing Hu ◽  
Simao Chen
Keyword(s):  
Three Dimensional ◽  
Phase Shifting ◽  
Phase Shifting Method

Post-processing deflectometry grid images using particle image velocimetry analysis

2021 ◽  
pp. 1-13
Author(s):  
Patrick O'Donoughue ◽  
Olivier Robin ◽  
Alain Berry ◽  
Alain Le Bot ◽  
Kevin Rouard
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Mechanical Vibration ◽  
Hybrid Approach ◽  
Phase Shifting ◽  
Integer Number ◽  
Analysis Tool ◽  
Full Field ◽  
Image Velocimetry ◽  
Phase Shifting Method

Abstract Deflectometry is a full-field optical technique for surface slope measurement based on recording the deformation of a grid image. A hybrid method is explored in which the grid images from a deflectometry measurement are processed using a particle image velocimetry analysis tool. The hybrid approach is compared to a common phase shifting algorithm for grid images based on a windowed discrete Fourier transform. The resulting slope maps compare well with those identified using the spatial phase shifting procedure. While the traditional phase shifting method has a tuning requirement that limits the optical setup to configurations that produce an integer number of pixels per grid period in the image, the use of particle image velocimetry analysis omits this calibration step. The applicability of an existing turnkey tool to perform full-field vibration imaging using deflectometry can benefit to research concerning mechanical vibration and related experimental methods.

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