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A fast and precise three-dimensional measurement system based on multiple parallel line lasers

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Chinese Physics B 2021年第2期30卷 276-284页

作者： Yao Wang Bin Lin State Key Laboratory of Modern optical Instrumentation CNERC for Optical InstrumentsZhejiang UniversityHangzhou 310027China

This paper conducts a trade-off between efficiency and accuracy of three-dimensional(3 D)shape measurement based on the triangulation principle,and introduces a flying and precise 3 D shape measurement method based on multiple parallel line ***,we establish the measurement model of the multiple parallel line lasers system,and introduce the concept that multiple base planes can help to deduce the unified formula of the measurement system and are used in simplifying the process of the ***,the constraint of the line spatial frequency,which maximizes the measurement efficiency while ensuring accuracy,is determined according to the height distribution of the ***,the simulation analyzing the variation of the systemic resolution quantitatively under the circumstance of a set of specific parameters is performed,which provides a fundamental thesis for option of the four system ***,for the application of the precision measurement in the industrial field,additional profiles are acquired to improve the lateral resolution by applying a motor to scan the 3 D ***,compared with the line laser,the experimental study shows that the present method of obtaining 41220 points per frame improves the measurement ***,the accuracy and the process of the calibration are advanced in comparison with the existing multiple-line laser and the structured light makes an accuracy better than 0.22 mm at a distance of 956.02 mm.

关键词： three-dimensional shape measurement multiple parallel line lasers fast and precise measurement parameter calibration

Optimized dithering technique in frequency domain for high-quality three-dimensional depth data acquisition

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Chinese Physics B 2019年第8期28卷 124-131页

作者： Ning Cai Zhe-Bo Chen Xiang-Qun Cao Bin Lin State Key Laboratory of Modern optical Instrumentation CNERC for Optical InstrumentsZhejiang UniversityHangzhou 310027China Research Institute of Zhejiang University-Taizhou Taizhou 318000China

On the basis of the objective functions,dithering optimization techniques can be divided into the intensity-based optimization technique and the phase-based optimization ***,both types of techniques are spatial-domain optimization techniques,while their measurement performances are essentially determined by the harmonic components in the frequency *** this paper,a novel genetic optimization technique in the frequency domain is proposed for highquality fringe *** addition,to handle the time-consuming difficulty of genetic algorithm(GA),we first optimize a binary patch,then join the optimal binary patches together according to periodicity and symmetry so as to generate a full-size *** is verified that the proposed technique can significantly enhance the measured performance and ensure the robustness to various amounts of defocusing.

关键词： fringe generation genetic algorithm frequency domain 3D shape measurement

A digital moiré fringe method for displacement sensors

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Frontiers of Information Technology & Electronic Engineering 2016年第9期17卷 946-953页

作者： Jian WU Ting-ting ZHOU Bo YUAN Li-qiang WANG State Key Laboratory of Modern optical Instrumentation CNERC for Optical Instrument Zhejiang University

In this study, a displacement measurement method based on digital moiré fringe is described and experimentally demonstrated. The method is formed by only one grating with a constant pitch. First, the magnified grating image is received by an imaging array and is sent to a computer. Then, the digital moiré fringes are generated by overlaying the grating image with its mirrored one. Finally, a specifically designed algorithm is used to obtain the fringes' phase difference before and after movement and calculate the displacement. This method has the effects of amplifying displacement and averaging the grating lines error, the same as the traditional moiré technique using two pieces of gratings. At the same time, the proposed system is much easier to assemble and the measurement resolution can be set more flexibly. One displacement measuring system based on this method was built up. Experiment results show that its measurement errors are less than 0.3 μm and less than 0.12 μm at the resolutions of 0.1 μm and 0.03 μm, respectively.

关键词： Digital moiré fringe Displacement measurement Grating

Multi-objective strategy to optimize dithering technique for high-quality three-dimensional shape measurement

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Chinese Physics B 2019年第10期28卷 381-386页

Dithering optimization techniques can be divided into the phase-optimized technique and the intensity-optimized technique. The problem with the former is the poor sensitivity to various defocusing amounts, and the problem with the latter is that it cannot enhance phase quality directly nor efficiently. In this paper, we present a multi-objective optimization framework for three-dimensional(3D) measurement by utilizing binary defocusing technique. Moreover, a binary patch optimization technique is used to solve the time-consuming issue of genetic algorithm. It is demonstrated that the presented technique consistently obtains significant phase performance improvement under various defocusing amounts.

关键词： three-dimensional(3D) shape measurement multi-objective dithering genetic algorithm

A new subdivision technique for grating based on CMOS microscopic imaging

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Chinese Optics Letters 2007年第5期5卷 278-280页

作者：袁波严惠民曹向群林斌 State Key Laboratory of Modern optical Instrumentation CNERC for Optical InstrumentZhejiang University

We propose a new subdivision technique directly subdividing the grating stripe by using complementary metal-oxide semiconductor （CMOS） microscopic imaging system combined with image processing. The corresponding optical system, subdivision principle, and image processing methods are illuminated. The relations of systemic resolution to subdivision number, grating period, magnifying power and tilt angle are theoretically discussed and experimentally checked on the Abbe comparator. The measurement precision for displacement of the proposed subdivision system is tested in the range of 5 mm and the maximum displacement error is less than.0.4μm. The factors contributing to the systemic error are also discussed.

关键词： Diffraction gratings Image processing optical systems

A new interpolating method based on the variation of spectra energy using CMOS array

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Chinese Optics Letters 2005年第2期3卷 80-82页

作者：汤天瑾曹向群陈洪璆林斌 cnerc for optical Instrument Zhejiang University Hangzhou 310027

A new interpolating method to enhance the resolution of gratings using complementary metal-oxide semiconductor （CMOS） according to the variation of soIne specified spectral light intensities during the motion of scale grating in a periodic separation is proposed. CMOS image sensor （pixel array 648 × 488） was also introduced as receiving device and its stability was verified experimentally. Many factors m the experiment were analyzed theoretically and contrasted with experiment. The advantages of this novel method were featured by CMOS and the specified spectral variation of the energy distribution was discussed.

关键词： CMOS A new interpolating method based on the variation of spectra energy using CMOS array

Filament diameter measurement system based on dual diffraction

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Chinese Optics Letters 2015年第12期13卷 8-11页

作者：杨松涛陈波林斌曹向群 cnerc for optical instruments Zhejiang University State Key Laboratory of Modern optical Instrumentation Zhejiang University Public Security Department of Zhejiang Province

This Letter proposes a brand-new filament diameter measurement method based on what is called ＂dual diffraction,＂ in that a grating is added behind the filament to make full use of its subdivision and amplification characteristics. Higher measurement accuracy is achieved by this method compared with the traditional diffraction method. To verify its accuracy, three standard filaments with nominal values of 100.2, 120.1, and 140.8 μm are measured by the dual diffraction method and traditional diffraction method under the same experimental conditions. The relative measurement errors of the new method are less than 0.75%, and its average relative error is reduced by 56% compared with the traditional diffraction method.

关键词： Volume measurement

A novel atomic force microscope operating in liquid with open probe unit and optimized laser tracking system

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Chinese Optics Letters 2009年第10期7卷 891-893页

作者：伏霞张冬仙章海军 State Key Laboratory of Modern optical instruments Zhejiang University

A novel atomic force microscope （AFM） for large samples to be measured in liquid is developed. An innovative laser beam tracking system is proposed to eliminate the tracking and feedback errors. The open probe design of the AFM makes the operation in liquid convenient and easy. A standard 1200-lines/mm grating and a sheet of filter paper axe imaged respectively in air and liquid to confirm its performance. The corrosion behavior of aluminum surface in 1-mol/L NaOH solution is further investigated by the AFM. Experimental results show that the system can realize wide range （20 × 20 （μm）） scanning for large samples both in air and liquid, while keeping nanometer order resolution in liquid by eliminating the tracking and feedback error.

关键词： Air filters Atomic force microscopy Navigation Paper sheeting Probes

Capillary method for measuring near-infrared spectra of microlitre volume liquids

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 171-175页

作者： YUAN Bo MURAYAMA Koichi Department of Information Science and Optoelectronic Engineering State Key Laboratory of Modern Optical Instrumentation CNERC for Optical Instrument Zhejiang University Hangzhou 310027 China Department of Biochemistry and Biophysics Gifu University School of Medicine Gifu 500-8705 Japan

The present study theoretically explored the feasibility of the capillary method for measuring near-infrared (NIR) spectra of liquid or solution samples with microlitre volume, which was proposed in our previous studies. Lambert-Beer absorb- ance rule was applied to establish a model for the integral absorbance of capillary, which was then implemented in numerical analyses of the effects of capillary on various spectral features and dynamic range of absorption measurement. The theoretical speculations indicated that the capillary method might be used in NIR spectroscopy, which was further supported by the empirical data collected from our experiments by comparison between capillary NIR spectra of several organic solvents and cuvette cell NIR spectra.

关键词： Near-infrared (NIR) spectroscopy Capillary Cuvette cell Numerical analysis