• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.389-395
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• 1995

The bicycle production process mainly consists of welding process of pipes and its quality is determined by geometrical symmetry of arrangement of welded pipes. Hence, manual quality control of bicycle frames was very ineffecient and required much time in dimensional inspection and does not reserve high precision. In this paper we introduce a method of fast and accurate dimensional inspection of bicycle frame, using the Stereo Vision system and related some image processing techniques.

• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.437-446
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• 2006

Laser vision inspection systems are becoming popular for automated inspection of manufactured components. The performance of such systems can be enhanced by improving accuracy of the hardware and robustness of the software used in the system. This paper presents a new approach for enhancing the capability of a laser vision system by applying hardware compensation and using efficient analysis software. A 3D geometrical model is developed to study and compensate for possible distortions in installation of gantry robot on which the vision system is mounted. Appropriate compensation is applied to the inspection data obtained from the laser vision system based on the parameters in 3D model. The present laser vision system is used for dimensional inspection of car chassis sub frame and lower arm assembly module. An algorithm based on simplex search techniques is used for analyzing the compensated inspection data. The details of 3D model, parameters used for compensation and the measurement data obtained from the system are presented in this paper. The details of search algorithm used for analyzing the measurement data and the results obtained are also presented in the paper. It is observed from the results that, by applying compensation and using appropriate algorithms for analyzing, the error in evaluation of the inspection data can be significantly minimized, thus reducing the risk of rejecting good parts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.379-383
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• 1995

In this paper, vision inspection module for dimensional measurement has been developed. For high accuracy of CMM, camera calibration and edge detection with subpixel accuracy have been implemented. In measurement process, the position of vision probe can be recognized in PC by serial communication with CMM controller. The developed vision inspection module can be widely applied to the practical measurement process.

• IE interfaces
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• v.4 no.2
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• pp.43-51
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• 1991

A line search method is developed to locate all the conerpoints of 2-dimensional polygon images for inspection purposes. This optimization-based method is used to approximate a 2-D curved object by a polygon. This scheme is also developed for inspection of objects in industrial environment. The inspection includes dimensional verification and pattern matching which compares a 2-D image of an object to a pattern image. The method proves to be computationally efficient and accurate for real time application.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.97-102
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• 2002

Two dimensional Analysis has been applied to most of tunnel lining design in these days. Two dimensional analysis uses beam or curved beam element for finite element method. But because the behaviors of tunnel concrete lining structure is near to shell, it is required to model the tunnel lining as shell structure for safety design of tunnel lining structure. In this paper, two dimensional analysis by beam element and the three dimensional analysis by shell element of tunnel concrete lining are studied, in which 3 type of tunnel lining and lateral pressure factors are considered. As results of the study, three dimensional analyses of the behavior of tunnel concrete lining structure considering lateral pressure factor shows that the moment of three dimensional analysis is greater than those of two dimensional analysis. The results shows that three dimensional analysis is necessary for safety design of tunnel lining.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.492-498
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• 1994

The bicycle production process mainly consists of welding process of pipes and its quality is determined by geometrical symmetry of arrangement of welded pipes. Hence, manual quality control of bicycle frames was very inefficient and required much time in dimentional inspection and does not reserve high precision. In this paper we introduce a method of fast and accurate dimensional inspection of bicycle frame using the Stereo Vision system and related some image processing techniques.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.82-90
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• 2005

Recently, the in-line vision inspection has become the subject of growing research area in the visual control systems and robotic intelligent fields that are required exact three-dimensional pose. The objective of this article is to study the pc based in line visual inspection with the hand-eye structure. This paper suggests three dimensional structured light measuring principle and design method of laser sensor header. The hand-eye laser sensor have been studied for a long time. However, it is very difficult to perform kinematical analysis between laser sensor and robot because the complicated mathematical process are needed for the real environments. In this problem, this paper will propose auto-calibration concept. The detail process of this methodology will be described. A new thinning algorithm and constrained hough transform method is also explained in this paper. Consequently, the developed in-line inspection module demonstrate the successful operation with hole, gap, width or V edge.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.6
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• pp.590-596
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• 2004

Neural network-based signal classification systems are increasingly used in the analysis of large volumes of data obtained in NDE applications. Ultrasonic inspection methods on the other hand are commonly used in the nondestructive evaluation of welds to detect flaws. An important characteristic of ultrasonic inspection is the ability to identify the type of discontinuity that gives rise to a peculiar signal. Standard techniques rely on differences in individual A-scans to classify the signals. This paper proposes an ultrasonic signal classification technique based on the information tying in the neighboring signals. The approach is based on a 2-dimensional Fourier transform and the principal component analysis to generate a reduced dimensional feature vector for classification. Results of applying the technique to data obtained from the inspection of actual steel welds are presented.

• Journal of KIBIM
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• v.3 no.3
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• pp.1-8
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• 2013

In general, a two-dimensional platform were used to manage the structural inspection information. But we performed a study on utilizing 3D model to input and display the information of structure inspection. Coarse and Fine model of structure were used to input the information. 3D model combined with database built from record plan and field inspections data and rating will provide more intuitive and effective environment for inspectors in bridge maintenance.

• International journal of advanced smart convergence
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• v.8 no.3
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• pp.39-45
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• 2019

This paper presents an optical technique for the three-dimensional (3D) shape inspection of micro solder balls used in ball-grid array (BGA) packaging. The proposed technique uses an optical source composed of spatially arranged light-emitting diodes (LEDs) and the results are derived based on the specular reflection characteristics of the micro solder balls for BGA A vision system comprising a camera and LEDs is designed to capture the reflected images of multiple solder balls arranged arbitrarily on a tray and the locations of the LED point-light-source reflections in each ball are determined via image processing, for shape inspection. The proposed methodology aims to determine the presence of defects in 3D BGA shape using the statistical information of the relative positions of multiple BGA balls, which are included in the image. The presence of the BGA balls with large deviations in relative position imply the inconsistencies in their shape. Experiments were conducted to verify that the proposed method could be applied to inspection without sophisticated mechanism and productivity problem.