• Journal of the Korean Society for Precision Engineering
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• v.28 no.9
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• pp.1094-1102
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• 2011

Recent trends for the miniaturization and weight reduction of portable electronic parts is the use of subminiature components. Assembly of the miniaturized components requires subminiature screws of which pitch sizes are in a micrometer scale. To produce such a subminiature screw with high precision threads, not only a precision forming technology but also high-precision measurement technique is required. In the present work, a vision inspection system is developed to measure the thread profile of a subminiature screw. Optical simulation based on a ray tracing method is used to design and analyze the optical system of the vision inspection apparatus. Through this simulation, optical performance of the developed vision inspection system is optimized. The image processing algorithm for the precision screw inspection is also discussed.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.521-524
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• 2004

Recently, acgis of authentication and crcator's copyright has become a matter of great concern by the diffusion of multimedia technique and the growth of the internet and the easily duplicated property of digital data. Consequently, many active researches have been made to protect copyright and to assure integrity by inserting watermark into the digital data. In this paper, watermark is repealed through the entire image and adapted to the content of the image. Achieved by an underlying process of transforming the digital image to the frequency domain by wavelet transform, which has three (vertical, horizontal, diagonal) directions and Multi-resolution features, and then choosing frequency area inferior to the human perceptibility and significant for invisible and robust watermark. We realize wavelet based image watermarking using Machine Vision of LabVIEW.

• Journal of Biosystems Engineering
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• v.27 no.2
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• pp.143-150
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• 2002

Several researches for site-specific weed control have tried to increase accuracy of weed detection with machine vision technique. However, there is a problem which needs substantial time to perform site-specific spraying. Therefore, new technology for real-time precision spraying system is needed. This research was executed to develope the new technology to estimate weed density and size in real time, and to conduct a real-time site-specific spraying. It would effectively reduce herbicide amounts applied for a crop field. The real-time precision spraying system consisted of a Differential Global Positioning System (DGPS) with an error of 2 cm, a machine vision system, a geomagnetic sensor for correction of view point of CCD camera and an automatic sprayer with separately controlled nozzle. The weed density was calculated with comparison between position information and a pre-designed electronic map. The position information was obtained in real time using the DGPS and the machine vision. The electronic map contained a position database of crops automatically constructed when seeding. The developed system was tested on an experimental field of Seoul National University. Success rate of the spraying was about 61%.

• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.63-71
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• 2023

Metaverse is a modern new technology that is advancing quickly. The goal of this study is to investigate this technique from the perspective of computer vision as well as general perspective. A thorough analysis of computer vision related Metaverse topics has been done in this study. Its history, method, architecture, benefits, and drawbacks are all covered. The Metaverse's future and the steps that must be taken to adapt to this technology are described. The concepts of Mixed Reality (MR), Augmented Reality (AR), Extended Reality (XR) and Virtual Reality (VR) are briefly discussed. The role of computer vision and its application, advantages and disadvantages and the future research areas are discussed.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.39-43
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• 2017

Development of vision system as a nondestructive evaluation system can be very useful in screening the defective mechanical parts before they are assembled into the final product. Since the tens of thousands of the mechanical parts are used in an automobile carefully inspecting the quality of the mechanical parts is very important to maximize the performance of the automobile. To sort out the defective mechanical parts before they are assembled, auto parts fabrication companies employ various inspection systems. Nondestructive evaluation systems are getting rapidly popular among various inspection systems. In this study, we have developed a vision system to inspect the inside of the brake caliper, a part that is used to compose a brake which is the most important to the safety of the drivers and the passengers. In a brake caliper, a piston is pushed against the brake disk by oil pressure, causing a friction to damp the rotation of the wheel. Inside the caliper, a groove is positioned to adopt an oil seal to prevent the oil leaks. Inspecting the groove with our vision system, we could examine the existence of the contaminants which are normally the residual tiny pieces from the machining process. We used a high resolution GigE camera, 360 degree lens to look in the inside view of the caliper at once, and a special illumination system in this vision system. We used the edge detection technique to successfully detect the contaminants which were in the form of small metal chips. Labview graphical program was used to process the digital data from the camera and to display the vision and the statistics of the contaminants. We were very successful in detecting the contaminants from the various size calipers. We think we are ready to employ this vision system to the caliper production factories.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1665-1673
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• 2003

We propose an image-based three-dimensional shape determination system. The shape, and thus the three-dimensional coordinate information of the 3-D object, is determined solely from captured images of the 3-D object from a prescribed set of viewpoints. The approach is based on the shape-from-silhouette (SFS) technique, and the efficacy of the SFS method is tested using a sample data set. The extracted three-dimensional shape is modeled with polygons generated by a new iterative triangulation algorithm, and the polygon model can be exported to commercial software. The proposed system may be used to visualize the 3-D object efficiently, or to quickly generate initial CAD data for reverse engineering purposes, including three dimensional design applications such as 3-D animation and 3-D games.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.776-779
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• 1987

This paper describes a technique for measuring the volume of a pile of powder in a visual way. The volume of a fragile object whose shape is easily transformed by a slight touch of another object must be measured without any contact with it. This can be achieved by applying a three-dimensional shape reconstruction technique employed in computer vision. We have developed a measurement system that finds the volume of a pile of powder by employing a range finder, and performed an experiment of determining the volume of PVC powder piled on a table. The result of the experiment was satisfactory.

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1104-1113
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• 2000

This paper proposes an efficient reverse engineering technique for compound surfaces using a boundary detection method. This approach consists in extracting geometric edge information using a vision system, which can be used in order to drastically reduce geometric errors in the vicinity of compound surface boundaries. Through the image-processing technique and the interpolation process, boundaries are reconstructed by either analytic curves (e. g. circle, ellipse, line) or parametric curves (B-spline curve). In other regions, except boundaries, geometric data are acquired on CMM as points inspected using a touch type probe, and then they are interpolated on several surfaces using a B-spline skinning method. Finally, the boundary edge and the skinned surfaces are combined to reconstruct the final compound surface. Through simulations and experimental works, the effectiveness of the proposed method is confirmed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.4
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• pp.159-165
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• 2012

The accurate focusing position should be determined for accurate measurements In VMS. Camera lens focusing is an important problem in computer vision and video measuring systems (VMS) that use CCD cameras and high precision XYZ stages. Camera focusing is a very important step in high precision measurement systems that use computer vision technique. The auto focusing process consists of two steps, the focus value measurement step and the exact focusing position determination step. It is suitable for eliminating high frequency noises with lower processing time and without blurring. An automatic focusing technique is applied to measure a crater with a one-dimensional search algorithm for finding the best focus. Throughout this paper, the suggested algorithm for the Auto focusing was combined with the learning. As a result, it is expected that such a combination would be expanded into the system of recognizing voices in a noisy environment.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.223-229
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• 2003

Tool wear monitoring is an important technique in the flexible manufacturing system. This paper studies the end mill wear detection using CCD camera and pattern recognition method. When the end mill working in the machining center, the bottom edge of the end mill geometry change, this information is used. The CCD camera grab the new and worn tool geometry and the area of the tool geometry was compared. In this result, when the values of the subtract worn tool from new tool end in 200 pixels, it decides the tool life. This paper proposed the new method of the end mill wear detection.