A study on length measurement method of hot large forgings based on binocular vision system

Wang, Bangguo

doi:10.1016/j.measurement.2022.111586

Cited by 12 publications

(9 citation statements)

References 16 publications

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“…With the rapid development of digital imaging technology and computer vision, binocular vision measurement technology, as a vision-based measuring technology, has become one of the most critical technologies because of its high precision and stability [14]. Tis vision technology can sense spatial displacement and has the potential to solve the limitations of the aforementioned commonly used displacement sensors [15]. Visual metrology usually comprises several artifcial targets and two cameras.…”

Section: Introductionmentioning

confidence: 99%

Wireless Binocular Stereovision Measurement System Based on Improved Coarse-to-Fine Matching Algorithm

Wang

Xiao

Gong

et al. 2023

Structural Control and Health Monitoring

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To cope with the challenges some commonly used displacement sensors may face in structural health monitoring, we proposed a wireless binocular stereovision measurement system based on the improved coarse-to-fine matching algorithm. The vision measurement system can perceive multipoint three-dimensional displacement and consists of two cameras, one remote control unit, and a solar panel. The improved coarse-to-fine matching algorithm only requires a flat surface with some painted textures instead of designed markers with refined patterns (circle, square, and chessboard). Omitting the textures keeps a balance between measurement accuracy and the burden of the target installation in the actual field of structural health monitoring. The proposed coarse-to-fine matching algorithm utilizes scale-invariant feature transform (SIFT) points to generate a robust initial guess and combines improved least squares matching (LSM) algorithm for advanced corresponding point matching. A precalculated look-up table for interpolation and parallel computation is used for higher matching precision and computational efficiency. Several experiments were conducted to present the accuracy and feasibility of the proposed metering system. A simulation test, an indoor shaking table test with several commonly used displacement sensors, and an outdoor experiment consider the natural condition. Experimental results verified that the proposed matching methodology could achieve 0.2-pixel matching accuracy, 0.1 mm measuring precision in a laboratory, and millimeter-level precision in real conditions.

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Section: Introductionmentioning

confidence: 99%

Wireless Binocular Stereovision Measurement System Based on Improved Coarse-to-Fine Matching Algorithm

Wang

Xiao

Gong

et al. 2023

Structural Control and Health Monitoring

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“…Another technology for forging measurement is active close-range photogrammetry. This includes fringe projection systems 7,17,18 , active stereovision 6,[19][20][21][22][23][24][25][26][27] (using a projector or laser array to project feature points on the object), and laser profilers 10,[28][29][30] . However, a hot blank at forging temperatures of 800-1200 ° C emits light and thermal radiation that has characteristics similar to the radiation of a theoretical blackbody given by Planck's law, which could be a problem from the signal-to-noise ratio point of view.…”

Section: Introductionmentioning

confidence: 99%

Forging measurement using passive stereo vision

Vítek,

Hurník,

Vaverka

et al. 2023

Optical Measurement Systems for Industrial Inspection XIII

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Dimensional inspection during manufacturing of high-temperature forging workpieces is still an unsolved research topic. In this work, an approach to reconstruct the hot forging surface using passive stereovision was proposed. The challenges are the irregular thermal radiation of the forging in the visible spectrum, which is affected by scales, heat haze, and an unstable environment. Unlike the approaches presented in the literature, we use the radiated light, without an external light source. High dynamic resolution images were used to image the forging surface with highly varying brightness. The effect of optical filtering on the contrast of the fine surface structure was investigated and evaluated by spectral analysis of the images, with the best results obtained in the green spectrum. A comparison of feature detectors was performed for the specific surface structure of the hot forging. The best results in terms of density of reconstructed points were obtained using the KAZE method. The final verification of the achievable accuracy was performed in a measurement volume of approx. 500×400×350 mm. An 877 °C hot steel pipe sample was measured with a single point standard deviation error of 0.28 mm, which is an order of magnitude higher than under ideal conditions, but acceptable in comparison with manufacturing tolerances. Further developments could be related to the application of dense image matching, further investigation of interfering effects, and application of the proposed methods in the industrial environment.

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“…In generally, acupuncture are curative when the error range of acupoints coordinates is less than 5 mm. 9 At present, although artificial acupuncture is the mainstream treatment process, the research on acupuncture robots is becoming more and more popular, and the location of acupuncture points is still a very important part of acupuncture robots, where 3D human models can be used. 10 Acupoints positioning methods include regular-based methods and image-based methods in acupuncture robots.…”

Section: Introductionmentioning

confidence: 99%

“…However, the characteristics of the acupuncture points are often not obvious in 2D diagram. 8,9,[14][15][16][17][18] The features in 3D models are obvious relatively, 10 but there are not many studies on them. Recent researches more concentrate on 2D graph in computer vision, which mainly use digital image processing methods to obtain acupuncture points that can be located by many features on the human body surface.…”

Section: Introductionmentioning

confidence: 99%

“…Accurate identification of acupoints is an important part of clinical practice. In generally, acupuncture are curative when the error range of acupoints coordinates is less than 5 mm 9 . At present, although artificial acupuncture is the mainstream treatment process, the research on acupuncture robots is becoming more and more popular, and the location of acupuncture points is still a very important part of acupuncture robots, where 3D human models can be used 10…”

Section: Introductionmentioning

confidence: 99%

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Location of acupuncture points based on graph convolution and 3D deep learning in virtual humans

Zhou

2023

Computer Animation & Virtual

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Automatic acupoint searching is an indispensable part of intelligent acupuncture robot. Clinical practice have proofed that Dazhu, Fengmen and Xinshu, which could be located by Dazhui, are curative when these points are acupuncture. The existing methods are mainly based on regular or image. The regular‐based methods are based on the experience of physicians, and the accuracy will decrease for different patients; While the image‐based methods will lose some features in image. In order to solve the existing problems, we propose a novel graph convolution mixed with point cloud deep learning method. In this method, the skinned multi‐person linear model is regarded as a graph structure input, and the coarsened graph is obtained by graph convolution. After feeding the coarsened graph into the PointNet network, the coordinates of Dazhui are output. Different from the existing methods, the proposed method can directly label the results on the adaptive model, thus improving the accuracy on different models. An optimization method based on graph structure is introduced for better fit the predicted acupoints to the surface. In addition, a dataset marked with Dazhui is constructed for training. Experiments show that the accuracy of positioning could meet the requirements of needle application under certain circumstances.

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A study on length measurement method of hot large forgings based on binocular vision system

Cited by 12 publications

References 16 publications

Wireless Binocular Stereovision Measurement System Based on Improved Coarse-to-Fine Matching Algorithm

Wireless Binocular Stereovision Measurement System Based on Improved Coarse-to-Fine Matching Algorithm

Forging measurement using passive stereo vision

Location of acupuncture points based on graph convolution and 3D deep learning in virtual humans

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