A Robust Multi-camera 3D Ellipse Fitting for Contactless Measurements

Bergamasco, Filippo; Cosmo, Luca; Albarelli, Andrea; Torsello, Andrea

doi:10.1109/3dimpvt.2012.22

Cited by 15 publications

(9 citation statements)

References 20 publications

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“…The solution of equation 13is (y p1 , y q1 ) which equal to the solution of equation 14, (y p2 , y q2 ); combing equations (8), (9), (13) and (14), we have…”

Section: Optimizing Edge Points Based On Epipolar Geometrymentioning

confidence: 99%

An accurate and robust method for the measurement of circular holes based on binocular vision

Xia

Zhao

et al. 2019

Meas. Sci. Technol.

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Circular holes in industrial parts are a very important feature which are often used as assembly references for other parts, so accurate measurement is required. Measurement of circular holes based on computer vision is a promising method but also very challenging, because it is tricky to find the edge of a hole accurately in an image. In this paper, an accurate and robust method for the measurement of circular holes is proposed. Firstly, highly trusted edge points of the hole are found based on pixel intensity information. Secondly, a new energy function model based on the epipolar geometry constraint is introduced to obtain the optimal edges of the hole. Finally, a spatial circular hole is accurately reconstructed by using the points on the optimized edges as input to a threedimensional reconstruction method. Our experimental result shows that the proposed method could measure various circular holes from different views with an error of around 0.05 mm.

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“…The solution of equation 13is (y p1 , y q1 ) which equal to the solution of equation 14, (y p2 , y q2 ); combing equations (8), (9), (13) and (14), we have…”

Section: Optimizing Edge Points Based On Epipolar Geometrymentioning

confidence: 99%

An accurate and robust method for the measurement of circular holes based on binocular vision

Xia

Zhao

et al. 2019

Meas. Sci. Technol.

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“…In engineering applications, the diameter of the tubes is generally less than 8 mm. In the previous studies (Wade et al , 1997; Bergamasco et al , 2012), the end points of the tube were calculated by fitting the end edge of the tube. However, these methods are difficult to apply to a small-diameter tube.…”

Section: Tube Inspection Methodsmentioning

confidence: 99%

A multi-vision-based system for tube inspection

Jin

Liu

et al. 2018

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Purpose Geometric errors are common in metallic bent tubular parts. Thus, tubes should be inspected and fixed before welding with the joints first. After welding, the relative position of the joints is also necessary to be inspected to judge whether the tube can be assembled reliably. Therefore, the inspection plays an important role in the tube’s assembly. The purpose of this paper is to propose a multi-vision-based system designed to inspect the tube and the relative position of the joints. Design/methodology/approach For the tube inspection, the small cylinders are taken as the primitives to reconstruct the tube using the multi- vision-based system. Then, any geometric error in the tube can be inspected by comparing the reconstructed models and designed ones. For joints’ inspection, authors designed an adapter with marked points, by which the system can calculate the relative position of the joints. Findings The reconstruction idea can recognise the line and arc segments of a tube automatically and resolve the textureless deficiency of the tube’s surface. The joints’ inspection method is simple in operation, and any kinds of joints can be inspected by designing the structure of the adapters accordingly. Originality/value By experimental verification, the inspection precision of the proposed system was 0.17 mm; the inspection time was within 2 min. Thus, the system developed can inspect a tube effectively and automatically. Moreover, authors can determine how the springback of the arcs behaves, allowing in-process springback prediction and compensation, which can reduce geometric errors in the tubes given the present bending machine accuracy.

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“…Sheet metal parts are widely used in automobile transportation, aerospace and other fields because of their excellent performance such as low density, high strength and good forming ability. Hole contour information is common and important feature in sheet metal parts that requires 3D measurement to ensure forming quality and product safety performance [1][2][3] . Existing 3D contour measurement methods for holes can be mainly divided into two categories: 1) Contour reconstruction based on measurement points 4 .…”

Section: Introductionmentioning

confidence: 99%

Fringe projection based 3D contour measurement method for holes on sheet metal parts

Zhang

Huang

et al. 2023

International Conference on Optical and Photonic Engineering (icOPEN 2022)

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Holes are common and important feature information in sheet metal parts, and play a decisive role in product production and assembly. The 3D contour reconstruction method based on passive binocular vision has been widely used in hole measurement due to its high accuracy and robustness. It can obtain dimensional data such as diameter and center of round holes, but there are still problems in measurement accuracy and integrity, and it is difficult to accurately measure specialshaped holes. Aiming at these issues, a fringe projection based 3D contour measurement method for holes on sheet metal parts is proposed. In this method, two constant movements are performed on the extracted contour curve to the surrounding area, and the 3D contour points can be reconstructed according to the phase matching. Therefore, the real 3D contour is reconstructed inversely according to the corresponding points of the previous two reconstructed contours. With this method, contours only need to be extracted on one image, so it can reduce the effect of inconsistency in contour extraction. In addition, the accuracy and integrity of the 3D contour can be guaranteed by using high-quality phase matching of the sheet metal area. The experimental results show that this method can achieve accurate and complete 3D contour reconstruction for sheet metal holes of various shapes, and the accuracy can reach 0.08mm.

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A Robust Multi-camera 3D Ellipse Fitting for Contactless Measurements

Abstract: Ellipses are a widely used cue in many 2D and 3D object

Cited by 15 publications

References 20 publications

An accurate and robust method for the measurement of circular holes based on binocular vision

An accurate and robust method for the measurement of circular holes based on binocular vision

A multi-vision-based system for tube inspection

Fringe projection based 3D contour measurement method for holes on sheet metal parts

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