scholarly journals Three-Dimensional Mirror Surface Measurement Based on Local Blur Analysis of Phase Measuring Deflectometry System

2020 ◽  
Vol 37 (5) ◽  
pp. 763-771
Author(s):  
Hongyu Sun ◽  
Le Wang ◽  
Zhan Song ◽  
Geng Chen
Keyword(s):  
Measurement Techniques ◽  
Three Dimensional ◽  
Block Matching ◽  
Surface Measurement ◽  
Mirror Surface ◽  
Reconstruction Accuracy ◽  
Surface Reflection ◽  
Block Matching Algorithm ◽  
Reflective Mirror ◽  
Spatially Varying

Despite the marked progress in recent years, structured light-based three-dimensional (3D) measurement techniques still have difficulty in capturing mirror surface reflection. The accuracy of 3D reconstruction for mirror objects should be further improved to adapt to the high reflectivity and curvature of such objects. To improve the stripe definition and reconstruction accuracy of highly reflective mirror objects, this paper analyzes the local blur of defocus stripes in phase measuring deflectometry (PMD) system, and presents a method to analyze the spatially varying defocusing and de-blurring, with the aid of a 3D block matching algorithm, thereby focusing on defocus stripes. Experimental results show that the proposed method can achieve micron-level reconstruction accuracy of standard flat mirrors, and detect the defects on highly reflective mirror objects at a high precision.

The Three-Dimensional Surface Topographic Characterisation of Diamond Grinding Wheels

2010 ◽  
Vol 126-128 ◽  
pp. 690-695
Author(s):  
David Lee Butler
Keyword(s):  
Measurement Techniques ◽  
Three Dimensional ◽  
Surface Measurement ◽  
Grinding Wheel ◽  
Profile Measurement ◽  
Detailed Knowledge ◽  
Grinding Wheels ◽  
Diamond Grinding ◽  
Insight Into ◽  
Dimensional Surface

Surface measurement using three-dimensional stylus instruments is a relatively new technique that offers numerous advantages over more traditional profilometry methods. The information generated is, unlike profile measurement, less subjective and more statistical providing additional insight into the surface structure. One application of surface measurement that has encountered problems when using the profilometry method is that of grinding wheel characterisation. The wheel surface texture (topography) and the conditions under which it is generated have a profound effect upon the grinding performance as characterised by the grinding forces, power consumption, temperature, and surface integrity of components. A detailed knowledge of the nature of the topography of the grinding wheel would provide further insight into surface interactions between the wheel and workpiece as well as enabling improved control of the grinding process in general. In this paper four diamond grinding wheels of 91 and 181 micron grit size were subjected to differing dressing conditions to produce varying final wheel topographies. Three-dimensional surface measurement techniques were employed to quantitatively characterise the topographic change and provide an aerial estimation of the number of cutting grains. The results demonstrate that the techniques can distinguish between a worn and dressed wheel. In addition, the parametric values generated from the various surfaces can aid the user in determining when re-dressing is required.

scholarly journals A Framework for Identification of Healthy Potted Seedlings in Automatic Transplanting System Using Computer Vision

2021 ◽  
Vol 12 ◽  
Author(s):  
Xin Jin ◽  
Chenglin Wang ◽  
Kaikang Chen ◽  
Jiangtao Ji ◽  
Suchwen Liu ◽  
...  
Keyword(s):  
Computer Vision ◽  
Three Dimensional ◽  
Comparison Method ◽  
Block Matching ◽  
Identification Accuracy ◽  
Position Information ◽  
Block Matching Algorithm ◽  
Fundamental Process ◽  
Vegetable Seedlings ◽  
Vegetable Cultivation

Automatic transplanting of seedlings is of great significance to vegetable cultivation factories. Accurate and efficient identification of healthy seedlings is the fundamental process of automatic transplanting. This study proposed a computer vision-based identification framework of healthy seedlings. Vegetable seedlings were planted in trays in the form of potted seedlings. Two-color index operators were proposed for image preprocessing of potted seedlings. An optimal thresholding method based on the genetic algorithm and the three-dimensional block-matching algorithm (BM3D) was developed to denoise and segment the image of potted seedlings. The leaf area of the potted seedling was measured by machine vision technology to detect the growing status and position information of the potted seedling. Therefore, a smart identification framework of healthy vegetable seedlings (SIHVS) was constructed to identify healthy potted seedlings. By comparing the identification accuracy of 273 potted seedlings images, the identification accuracy of the proposed method is 94.33%, which is higher than 89.37% obtained by the comparison method.

Surface Measurement Techniques in Machine Vision

2019 ◽  
pp. 79-104 ◽  
Author(s):  
Oscar Real Real ◽  
Moises J. Castro-Toscano ◽  
Julio Cesar Rodríguez-Quiñonez ◽  
Oleg Serginyenko ◽  
Daniel Hernández-Balbuena ◽  
...  
Keyword(s):  
Contact Surface ◽  
Computational Models ◽  
Vision System ◽  
Operation Mode ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Surface Measurement ◽  
Operating Modes ◽  
Surface Measurements ◽  
Basic Equations

Surface measurement systems (SMS) allow accurate measurements of surface geometry for three-dimensional computational models creation. There are cases where contact avoidance is needed; these techniques are known as non-contact surface measurement techniques. To perform non-contact surface measurements there are different operating modes and technologies, such as lasers, digital cameras, and integration of both. Each SMS is classified by its operation mode to get the data, so it can be divided into three basic groups: point-based techniques, line-based techniques, and area-based techniques. This chapter provides useful information about the different types of non-contact surface measurement techniques, theory, basic equations, system implementation, actual research topics, engineering applications, and future trends. This chapter is particularly valuable for students, teachers, and researchers that want to implement a vision system and need an introduction to all available options in order to use the most convenient for their purpose.

scholarly journals Three-dimensional Spatial Localization Based on Binocular Vsion

2021 ◽  
Author(s):  
Lan Zang ◽  
Kun Zhang ◽  
Chuan Tian ◽  
Chong Shen ◽  
Bhatti Uzair Aslam ◽  
...  
Keyword(s):  
Spatial Data ◽  
Recognition Rate ◽  
Three Dimensional ◽  
Target Object ◽  
Block Matching ◽  
Calibration Error ◽  
Search Range ◽  
Block Matching Algorithm ◽  
Binocular Stereo Vision ◽  
Binocular Stereo

Abstract In order to solve the problems of low accuracy and unstable system performance existing in binocular vision alone, this paper proposes a threedimensional space recognition and positioning algorithm based on binocular stereo vision and deep learning algorithms. First, a binocular camera for Zhang Zhengyou calibrated by several adjustments, calibration error will eventually set at 0.10pixels best, select and SAD in block matching algorithm in the algorithm, the matching point of the search range reduction, mitigation data for subsequent experiments burden. Then input the three-dimensional spatial data calculated by using the binocular ”parallax” principle into the Faster R-CNN model for data training, extract and classify the target features, and finally realize real-time detection of the target object and its position coordinate information. The analysis of experimental data shows that when the best calibration error is selected and the number of data training is sufficient, the algorithm in this paper can effectively improve the quality of target detection. The positioning accuracy and target recognition rate are increased by about 3%-5%, and it can achieve faster fps.

Disparity Estimation of 3-D Mesh for Stereo Video Coding

2014 ◽  
Vol 571-572 ◽  
pp. 835-839
Author(s):  
Jia Li Zheng ◽  
Tuan Fa Qin ◽  
Dong Xue Wei ◽  
Qin Huan Huang ◽  
Lin Deng
Keyword(s):  
Video Coding ◽  
Three Dimensional ◽  
Estimation Method ◽  
Block Matching ◽  
Disparity Estimation ◽  
Stereo Image ◽  
Matching Algorithm ◽  
Block Matching Algorithm ◽  
Mesh Model ◽  
Stereo Video

This paper proposed a disparity estimation method based on the three-dimensional (3-D) mesh model. The disparity estimation is a key step in stereo video coding. By employing intermediate view synthesis, the proposed technique simulate the nodals in the 3-D sureface of stereo image efficiently. Simulated results show that the proposed technique yields a visually more accurate prediciton than the block-matching algorithm.

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