A new optical flat surface measurement method based on machine vision and deflectometry

2016 ◽  
Author(s):  
Kewei E. ◽  
Dahai Li ◽  
Lijie Yang ◽  
Guangrao Guo ◽  
Mengyang Li ◽  
...  
Keyword(s):  
Machine Vision ◽  
Measurement Method ◽  
Flat Surface ◽  
Surface Measurement

Block Thickness Measurement of Using the Structured Light Vision

2018 ◽  
Vol 33 (01) ◽  
pp. 1955001 ◽  
Author(s):  
Fenghui Lian ◽  
Qingchang Tan ◽  
Siyuan Liu
Keyword(s):  
Machine Vision ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Thickness Measurement ◽  
Base Plane ◽  
Vision Measurement ◽  
Measurement Results ◽  
Measurement Equations ◽  
Structured Light Vision ◽  
Measuring Base

A method for measuring block thicknesses is proposed by the machine vision measurement. Equations of the measuring base plane and the light plane are formed by calibration. Then, the equation of the light strip image, that is, the image of the intersection between the base plane and light one, is established by the projection relation. Equation of the image of the light strip on the measured plane can be determined by the fitting. Since the light strip on the measuring base plane is parallel to one on the measured plane, the thickness of the measuring block is measured by using the two equations. The experiment evaluates the measurement accuracy of the measurement method and analyzes the influence of some factors on the measurement results.

Study on the Measuring and Positioning of the Rim Valve Hole Based on Machine Vision

2014 ◽  
Vol 711 ◽  
pp. 333-337 ◽  
Author(s):  
Fang Wang ◽  
Chao Kun Ma ◽  
Shan Qiang Dai ◽  
Chang Chun Li
Keyword(s):  
Image Processing ◽  
Machine Vision ◽  
Measurement Method ◽  
Ccd Camera ◽  
Servo Motor ◽  
Processing Characteristic ◽  
Linear Ccd ◽  
Hole Position ◽  
And Control

The author has designed a visual workbench to realize that the rim can rotate with the workbench. Meanwhile, the linear CCD camera records the rim’s circumference. The paper has explored the measurement method of getting the rim valve hole position using machine vision. The system can calculate the position of rim-hole and control the servo motor by image processing, characteristic recognizing and measuring to locate the position of wheel-hole automatically. And the paper has verified the accuracy of the method by experiments.

Accurate measurement method for tube’s endpoints based on machine vision

2016 ◽  
Vol 30 (1) ◽  
pp. 152-163 ◽  
Author(s):  
Shaoli Liu ◽  
Peng Jin ◽  
Jianhua Liu ◽  
Xiao Wang ◽  
Peng Sun
Keyword(s):  
Machine Vision ◽  
Measurement Method

Cooperative measurement method of multi-FOV for machine vision

2012 ◽  
Vol 20 (12) ◽  
pp. 2821-2829 ◽  
Author(s):  
何博侠 HE Bo-xia ◽  
何勇 HE Yong ◽  
卜雄洙 BU Xiong-zhu ◽  
商飞 SHANG Fei
Keyword(s):  
Machine Vision ◽  
Measurement Method

Research on the on-line dimensional accuracy measurement method of conical spun workpieces based on machine vision technology

Measurement ◽  
2019 ◽  
Vol 148 ◽  
pp. 106881 ◽  
Author(s):  
Gangfeng Xiao ◽  
Yongting Li ◽  
Qinxiang Xia ◽  
Xiuquan Cheng ◽  
Weiping Chen
Keyword(s):  
Machine Vision ◽  
Measurement Method ◽  
Dimensional Accuracy ◽  
Accuracy Measurement ◽  
On Line

A Direct Measurement Method of Yarn Evenness Based on Machine Vision

2015 ◽  
Vol 10 (4) ◽  
pp. 155892501501000 ◽  
Author(s):  
Junjuan Li ◽  
Baoqi Zuo ◽  
Chen Wang ◽  
Wenxiao Tu
Keyword(s):  
Machine Vision ◽  
Direct Measurement ◽  
Coefficient Of Variation ◽  
Measurement Method ◽  
Main Body ◽  
Quality Grade ◽  
Yarn Count ◽  
Image Acquisition System ◽  
Direct Measurement Method ◽  
Morphological Opening

In this paper, a new yarn evenness measurement method based on machine vision is introduced, which is a direct measurement process, as opposed to other methods. Two types of yarns (i.e., same yarn count but different quality grade and same quality grade but different yarn count) are measured to determine the coefficient of variation unevenness, which can be compared with the results of USTER ME100. The yarn images are continuously captured via an image acquisition system. To determine the main body of the yarn accurately, the yarn images are processed sequentially by a threshold segmentation and morphological opening operation. Next, the coefficient of variation (CV value) of the diameter is calculated to characterize the yarn evenness. Different image processing methods are used and compared to obtain a suitable method for use in the experiment. A more accurate, more efficient, and faster measurement system will meet requirements of the manufacturing of yarn; the suitable performance of the proposed method is illustrated using experimental results.

scholarly journals Multiposition Rotation Interference Absolute Measurement Method for High-Precision Optical Component Surfaces

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xueliang Zhu ◽  
Fengming Nie ◽  
Bingcai Liu ◽  
Ruikun Liu ◽  
Ailing Tian
Keyword(s):  
High Precision ◽  
Measurement Method ◽  
Absolute Measurement ◽  
Optical Component ◽  
Computational Method ◽  
Surface Measurement ◽  
Measurement Technology ◽  
Reference Mirror ◽  
Large Aperture ◽  
Absolute Measurements

Modern optical engineering requires increasingly sophisticated interferometry methods capable of conducting subnanometer scale measurements of the large aperture, high-precision optical component surfaces. However, the accuracy of interferometry measurement is limited to the accuracy with which the surface of the reference mirror employed in the interferometer system is known, and the influence of gravity-induced deformation cannot be ignored. This is addressed in the present work by proposing a three-flat testing method based on multiposition rotation interference absolute surface measurement technology that combines the basic theory of N-position rotation with the separability of surface wavefront functions into sums of even and odd functions. These functions provide the rotational symmetric components of the wavefront, which then enables the absolute surface to be reconstructed based on the N-position rotation measurements. In addition, we propose a mechanical clamping combined with computational method to compensate for the gravity-induced deformations of the flats in the multiposition rotation absolute measurements. The high precision of the proposed absolute surface measurement method is demonstrated via simulations. The results of laboratory experiments indicate that the combination compensation method provides the high-precision surface reconstruction outcomes. The present work provides an important contribution for supporting the interferometry measurement of large aperture, high-precision optical component surfaces.

Rapid Glass Refractive Index Measurement Method Based on Machine Vision

2017 ◽  
Vol 46 (11) ◽  
pp. 1112006
Author(s):  
李延风 LI Yan-feng ◽  
李修宇 LI Xiu-yu ◽  
杨柳 YANG liu
Keyword(s):  
Refractive Index ◽  
Machine Vision ◽  
Measurement Method ◽  
Refractive Index Measurement ◽  
Index Measurement

Dot Area Coverage Percentage Measurement Method for Plate Microscopic Image Based on Color Segmentation

2014 ◽  
Vol 536-537 ◽  
pp. 100-104
Author(s):  
Ju Hua Liu ◽  
Yao Hua Yi ◽  
Cong Li
Keyword(s):  
Machine Vision ◽  
Measurement Method ◽  
Detection Method ◽  
Measurement Precision ◽  
Area Coverage ◽  
Color Segmentation ◽  
Microscopic Image ◽  
Quality Detection ◽  
High Measurement ◽  
Plate Quality

On the basis of analysis the plate quality detection method in accordance with machine vision, Innovative dot area coverage percentage measurement method for plate microscopic image based on color segmentation was proposed in this paper. Plate microscopic image was transformed from RGB to HSI model. Then the plate microscopic image was segmented according to the saturation and the hue information. It was proved by experiments that the dot area coverage percentage measurement method based on color segmentation was provided with high measurement precision and good plate applicability.

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