• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.385-388
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• 2013

In this paper, we show the weakness of the image matching method by using MPEG-7 EHD(Edge Histogram Descriptor) and suggest how to improve this weakness by using image normalization. EHD algorithm is an image matching technique that collects edge's slope of distribution and same distribution. However, the EHD error rate is high because EHD is sensitive for changes of object distortion and rotation that will be matched. We improve matching performance by accurately extract edge information in image by using normalization. We compare and analyze the normalized EHD algorithm by using distortion and rotation and it shows robustness for changes of the size and rotation.

• The Journal of the Korea Contents Association
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• v.5 no.2
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• pp.221-228
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• 2005

The paper proposes the improved error diffusion halftoning system to enhance the edges using the spatial perceptual characteristics of the human visual system. The proposed method computes a spatial variation(SV), which is the difference between a pixel luminance and the average of its $3{\times}3$ neighborhood pixels' luminances weighted according to the spatial positioning. Information of edge enhancement(IEE) Is computed using the SV and the local average luminance. The IEE is added to the quantizer's input pixel and feeds into the halftoning quantizer. The quantizer produces the halftone image having the enhanced edge. The performance of the proposed method is compared with conventional methods by measuring the edge correlation. The halftone images by using the proposed method show better quality due to the enhanced edge. And the detailed edge is preserved in the halftone images by using the proposed method.

• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.503-513
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• 2020

This paper presents a method to evaluate denoising filters based on edge locations in their denoised images. Image quality assessment has often been performed by using structural similarity (SSIM). However, SSIM does not provide clearly the geometric accuracy of features in denoised images. Thus, in this paper, a method to localize edge locations with subpixel accuracy based on adaptive weighting of gradients is used for obtaining the subpixel locations of edges in ground truth image, noisy images, and denoised images. Then, this paper proposes a method to evaluate the geometric accuracy of edge locations based on root mean squares error (RMSE) and jaggedness with reference to ground truth locations. Jaggedness is a measure proposed in this study to measure the stability of the distribution of edge locations. Tested denoising filters are anisotropic diffusion (AF), bilateral filter, guided filter, weighted guided filter, weighted mean of patches filter, and smoothing filter (SF). SF is a simple filter that smooths images by applying a Gaussian blurring to a noisy image. Experiments were performed with a set of simulated images and natural images. The experimental results show that AF and SF recovered edge locations more accurately than the other tested filters in terms of SSIM, RMSE, and jaggedness and that SF produced better results than AF in terms of jaggedness.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.40-45
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• 2012

The glass edge sealing is one of the vacuum glazing core manufacturing process and it needs the high reliability for the vacuum keeping. Conventionally, the glass edge sealing had been being researched by the method that pasted the flit on the glass edge part and bonded two sheets of glass. But this way has the defect that can't make tempered glass. In order to remedy it's faults, in this paper, the glass edge was sealed by using the hydrogen mixture gas torch within the furnace. The parameter having an effect on the glass edge sealing through the basic test was set. And the correlation of the thickness of the glass edge and parameter were analyzed through the design of experiment. By using the Taguchi method, the optimal process condition for the glass edge sealing was drawn and the validity was verified.

• Journal of the Semiconductor & Display Technology
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• v.15 no.1
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• pp.56-64
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• 2016

It is generally accepted that the surface quality of wafer edge is mostly damaged by the vibrations of the edge grinding machine. The surface quality of wafer edge is supposed to be the most dominant factor of the cracks, scratches, burrs and chips on the edge surfaces, which are the main defects of the wafers. In this study, the structure of a wafer edge grinder has been investigated through the frequency response experiment and the computer simulation to find ways to suppress the vibrations from the structure. The main reasons of the structural vibrations were analyzed. And further the design alterations were deduced from the results of the experiment and the simulation, and applied to the machine to check the effects of those alterations and to eventually improve the structural stability. The result shows that the machine can have much improved stability with relatively simple design changes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.918-920
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• 2011

In this paper, a simple edge pattern classification method is proposed for detecting straight line segments in an image corrupted by impulse noise. Corrupted images have complicated edge patterns. To detect straight line from an complicated edge pattern, it is needed to simplify the entire edge. The proposed algorithm separates the entire edge into 4 directional partial edge patterns. Each line segment is separated from the partial edge image where several line segments are overlapped, and then the straight line is detected. The results of the experiments emphasize that the proposed algorithm is simple but accurate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.672-674
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• 2011

Edge contains important information to analyze the characteristics of the images. Edge detection has been a lot utilized in areas such as computer vision and image processing etc.. And sobel, prewitt, roberts are representative methods among the initially used methods. Although these conventional methods easily detect large change points of slope of brightness, optional directional edge detection abilities of conventional edge detection are not efficient. Therefore, in this paper, to complement the shortcomings of existing edge detection method, we proposed adaptive edge detection method considering direction information. through simulatioopn, we verify abilities of our method.

• Journal of KIISE:Software and Applications
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• v.34 no.11
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• pp.961-970
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• 2007

Since the usual conventional edge detectors employ the local differential derivatives, the detected edges are not uniform in their widths or some edges are missed out of the detection on magnified images. We employ a mapping from the exactly monotonic intensity distributions of ramp edges to the simple step functions of intensity, which is referred to as perfect sharpening map of ramp edges. This map is based on the non-local feature of intensity distribution and used to introduce a modified differentiation, in terms of which we can construct an efficient edge detector adaptive to the variation of edge width. By adopting the operator MADD in this paper, we developed an edge detector that works stably against the magnification of image or the variation of edge width. It is shown by comparing to the conventional algorithms that the proposed one is very excellent.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.644-652
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• 2002

Increasing demands for Electric Resistance Welded pipes of high quality with thick wall require c lose investigations in edge deformation by slitting, strip deformation during break down farming, and difference of circumferential length. In order to obtain good quality of a welding zone, it is necessary to predict the edge shape of the initial strip. The modeling of the multi-pass thick tube roll forming process with rigid plastic finite element method ultra the edge shape prediction of an initial strip with 2nd-degree polynomial regression method are presented. Edge shapes of initial strip have been analyzed by the finite element method and designed by the regression method to satisfy the requirements in target fin pass. It is concluded that the proposed edge design method results in optimal edge shapes sat string the design requirements.

• Journal of Chest Surgery
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• v.54 no.3
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• pp.165-171
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• 2021

As a percutaneous technique for the reduction of mitral regurgitation, the MitraClip system (Abbott Vascular, Abbott Park, IL, USA) for transcatheter edge-to-edge repair of the mitral valve was developed in 1998 and first used in 2003. Its main advantage is being less invasive than surgery, because it can be performed through a transcatheter approach without any hemodynamic compromise. Recent studies have shown that this procedure reduces symptoms and improves functional capacity with low complication rates. Two randomized clinical trials have investigated the use of this technique for functional mitral regurgitation. The Korean Ministry of Food and Drug Safety approved its use for degenerative mitral regurgitation in 2019, and this procedure started to be performed in Korea in January 2020. Its use for functional mitral regurgitation was also approved in Korea in 2020. In this article, recent evidence on transcatheter edge-to-edge repair of the mitral valve and our initial experiences in Korea will be reviewed.