• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.1996-2001
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• 2012

Visual inspection systems are widely proposed for the well formed surface materials like electronics parts. But the materials with ill reflection ability have many troubles when visual inspection system is introduced. We have developed a robust visual inspection system that can work well in spite of low reflection ratio and with much noise when truth model is not known in the mixed production line. A workpiece identification technique using k-means has been proposed to identify the type. Based on the identified type, a robust-to-noise segmentation method, called active contour, has been applied to segment the features from the image. Finally, Kalman filter has been applied to adapt the error variation. Experiment shows that performance is about to match the accuracy of manual measurement using projectors.

• Smart Structures and Systems
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• v.25 no.6
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• pp.733-749
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• 2020

This study presents a computer vision-based approach for representing time evolution of structural damages leveraging a database of inspection images. Spatially incoherent but temporally sorted archival images captured by robotic cameras are exploited to represent the damage evolution over a long period of time. An access to a sequence of time-stamped inspection data recording the damage growth dynamics is premised to this end. Identification of a structural defect in the most recent inspection data set triggers an exhaustive search into the images collected during the previous inspections looking for correspondences based on spatial proximity. This is followed by a view synthesis from multiple candidate images resulting in a single reconstruction for each inspection round. Cracks on concrete surface are used as a case study to demonstrate the feasibility of this approach. Once the chronology is established, the damage severity is quantified at various levels of time scale documenting its progression through time. The proposed scheme enables the prediction of damage severity at a future point in time providing a scope for preemptive measures against imminent structural failure. On the whole, it is believed that the present study will immensely benefit the structural inspectors by introducing the time dimension into the autonomous condition assessment pipeline.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.569-571
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• 2010

In this paper, we develop a vision inspection system for inspecting flaws on plastic products such as insufficient moldings, spots, scratches. The inspection algorithm for this system consist of image binarization for curved structure of plastic products, image noise removal using morphology operation, labeling methods for candidate regions and image filtering and calibration method for flaw inspection. In order to improve its performance, we also develop fast image processing algorithm based on GUI. To verify the effectiveness of this system, we conducted evaluation for the system accuracy and the inspection algorithm processing time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.826-828
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• 2014

Recently trend of product is miniaturization. As a result, We need products surface as well as products internal defect inspection. Generally, Inspection products in production process uses a lot of optical inspection. However, This is difficult to internal inspection of products. We used optical device instead of X-ray generator. At the same time, We have developed system to determine the product defect. First, obtain X-ray image from Machine vision function. Next, Measured value is recognize suitability within error range. otherwise recognize defect. Results presence of defective products can be stored by user.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.189-192
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• 2008

Generally, the inspection is hard work and needs a lot of time. So, this work contains subjectivity of inspector owing to carry out the visual evaluations through naked eye. Thus, the result of inspection is not objective and reliable. The purpose of this study is to develop new inspection technique to solve above problems and to provide convenient inspection work. We make a new inspection system using digital image processing technology. This program can stitch each image and detect cracks of surface of concrete bridge. Also, It can extract an investigation drawing from the picture. Also, this program is a kind of management tools designed to have some functions such as converting the image data obtained from cameras to Data-Base format, searching and storing the data. At first, we try to make a automatic extracting program. But, changed by semiautomatic method because of various problems. Through field experiments, the application of this inspection system with specialty software has proven to be much faster, safer, and reliable than the inspections carried out by the naked eyes in managing safety of the bridges. The new inspection method may be able to make the inspection of bridge more efficient and reliable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.343-348
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• 1992

Using the real-time image processing technique, we have developed an automatic visual inspection system which detects the defects of the surface muonted components in PCB( missing components, mislocation, mismounts, and reverse polarity, etc ) and collects the quality control and production management data. An image processing system based on a commercial parallel processor, TRANSPUTER by which the image processing time can be largely reduced was designed. Analyzing the collected data, the proposed inspection system contributes to the productivity improvement throughthe reduction of defective rate.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2275-2278
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• 2003

In this paper, we propose a visual inspection algorithm to detect can print-errors by using multi-camera and image valuing algorithm. The features of the algorithm are to use four cameras that are arranged with 90$^{\circ}$ between each other and to adopt a synthesized image model which represents whole surface of a can. Using the model, detection process is straight forward, namely it is comparing a partial region of the can to a specific region of the model where is previously marked.

• Journal of Korean Medical classics
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• v.23 no.1
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• pp.317-319
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• 2010

The collateral diagnosis method is unique in Traditional Chinese Medicine diagnosis methods which has important clinical value. In my article, the contents of the "Hwangjenaegyeong(黃帝內經)" related to this method is discussed. According to the site of inspection in the diagnosis process, there are five types as following: inspection of the face and surface, the thenar, the orifices, abdominal collaterals and finally the index finger of children. This method can inspire clinical practitioners.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.188-200
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• 2002

In this study, a pavement evaluation method is introduced by a case study of the measurement data obtained in Incheon International Airport. Based on the results obtained by both visual inspection and automobile inspection equipments, the pavement surface condition is evaluated and used for maintenance and rehabilitation strategy for pavement. In addition, the special attention was given to the back calculation and solution technique of E-modulus by FWD's deflection data in Pavement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.104-112
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• 2015

Non-contact surface wave transmission (SWT) measurements are used to evaluate the depth of a surface-breaking crack in concrete slabs. The author propose a measurement model that includes an appropriate configuration of the source and receivers, and a transmission function for the given configuration. A series of numerical simulations using a 3D finite element model is used to obtain the transmission function. Then, validity of a proposed model is verified through experimental studies. Two air-coupled sensors are used to measured surface waves across surface-breaking cracks with varying depths from 0mm to 100mm with intervals of 10mm in a concrete slab ($1500{\times}1500{\times}180mm^3$) in laboratory. As a result, the proposed method is demonstrated as to be effective for charactering the depth of a surface-breaking crack in concrete bridge deck with an average error of 10%. A discussion on practical applications of the proposed method is also included in this article.