• Proceedings of the KSME Conference
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• 2003.11a
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• pp.962-967
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• 2003

CFD data compression method based on supercompact multiwavelets is presented. High data compression can be achieved when taking advantage of the compact nature of multiwavelets. Thresholding technique is also a matter of primary concern in determining pressure ratio. In this paper, we apply thresholding for multiwavelets that considers the coefficient vector as a whole rather than thresholding individual elements. Various thresholding methods are described briefly. CFD data compression suggests that the multivariate thresholding method is suitable for supercompact multiwavelets.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.174-177
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• 2007

Trabecular bone can be accurately represented using image-based finite element modeling and analysis of these bone models is widely used to predict their mechanical properties. However, the choice of thresholding technique, a necessary step in converting grayscale images to finite element models which can thus significantly influence the structure of the resulting finite element model, is often overlooked. Therefore, we investigated the effects of thresholding techniques on micro-computed tomography (micro-CT) based finite element models of trabecular bone. Three types of thresholding techniques were applied to micro-CT images of trabecular bone which resulted in three unique finite element models for each specimen. Bone volume fractions and apparent moduli were predicted for each model and compared to experimental results. Our findings suggest that predictions of apparent properties agree well with experimental measurements regardless of the choice of thresholding technique in micro CT images of trabecular bone.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.108-114
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• 2003

This research describes a image-processing technique for the scratch detecting algorithm for ITO coated glass. We use the modified logical thresholding method (called adaptive logical thresholding method) for binarization of gray-scale glass image. This method is useful to the algorithm for detecting the scratch of ITO coated glass automatically without need of any prior information of manual fine-tuning of parameters.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.435-437
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• 1998

영상에 대한 영역분할은 영상에 대한 인식 시스템에서 가장 중요하고도 어려운 분야로 알려져 있다. 주로 사용되는 방법은 화소중심기법과 영역중심기법이 사용되는데, 화소중심기법은 적은 시간이 걸리는데 비해 영역분할 효과가 떨어지고, 영역중심기법은 상대적으로 양질의 영역분할 효과를 얻을 수 있지만 많은 시간이 걸린다. 본 논문에서는 영역분할에 대한 방법으로 thresholding방법을 이용한 2단계로 이루어진 영역분할 방법을 제안한다. 제안된 방법은 화소의 전역정보와 지역정보를 모두 사용하여 기존의 전역 thresholding방법에 비해 향상된 영역 분할을 수행하고, 지역정보를 이용하는 영역중심 기법에 비해 시간을 단축하는 효과를 가지고 있다. 첫 번째 단계에서는 기존에 알려진 전역 thresholding방법을 사용하여 영역분할을 하고, 두 번째 단계에서는 영상에 대해 미리 알려진 사전지식을 이용하여 영역분할이 제대로 되지 않은 영역을 구분하여 해당 영역에 대해서만 thresholding작업을 수행한다. 사용된 영상은 자궁경부 세포진 영상으로 대상이 되는 영역은 자궁경부 세포의 핵으로 제한하였다.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.1031-1036
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• 1999

A Hierarchical vector Quantization scheme is implemented and an optimal thresholding technique of quadtree segmentation for performing high quality low bit rate image compression is proposes. A mathematical model is constructed under the assumption that the standard deviations of sub-blocks are larger than or equal to the standard deviation of the upper level block which is generated by merging of sub-blocks. This thresholding technique based on the mathematical modeling allows producing about 1 dB improved performance in terms of PSNR at most ranges of bit rates over the quadtree coder, which is based on MSE for quadtree segmentation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.4
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• pp.85-94
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• 2012

Lane marking detection is essential to both ITS and DAS systems. The objective of this paper is to provide more robust technique for lane marking detection than traditional techniques by using scale-space technique. Variable thresholding that is based on the local statistics may be very effective for detecting such objects as lane markings that have prominent intensities. However, such techniques that only rely on local statistics have limitations containing irrelevant areas as well. We reduce the candidate areas by combining the variable thresholding result with cost-efficient horizontal 1D LoG filtered scale space. Through experiments using practical images, we could achieve significant improvement over the techniques based not only on the variable thresholding but also on the Hough transform that is another very popular technique for this purpose.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.368-375
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• 2010

Unlike document images, license plate images are mostly captured under uneven lighting conditions. In particular, a shadowed region has sharp intensity variation and sometimes that region has very high intensity by reflected light. This paper presents a new technique for thresholding license plate images. This approach consists of three parts. In the first part, it performs a rough thresholding and classifies the type of license plate to adjust some parameters optimally. Next, it identifies a shadow type and binarizes license plate images by adjusting the window size and location according to the shadow type. And finally, post-processing based on the cluster analysis is performed. Experimental results show that the proposed method outperformed five well-known methods.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.265-268
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• 1995

Signal averaging technique to improve signal-to-noise ratio has widely been used in various fields, especially in electrophysiology. Estimation of the EP(evoked potential) signal using the conventional averaging method fails to correctly reconstruct the original signal under EEG(electroencephalogram) noise especial]y when the latency times of the evoked potential are not identical. Therefore, a technique based on the bispectrum averaging was proposed for recovering signal waveform from a set o noisy signals with variable signal dalay. In this paper an improved bispectrum estimation technique of the RP signal is proposed using a confidence thresholding of the EP signal in frequency domain in which energy distribution of the EP signal is usually not uniform. The suggested technique is coupled with the conventional bispectrum estimation technique such as least square method and recursive method. Some results with simulated data and real EP signal are shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.298-301
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• 1992

A digital image processing approach has been adopted to measure the flank wear area, which is very difficult to measure using conventional techniques. Automatic thresholding of the gray-level values of an image is very useful in automated analysis of image. 1-D entropy thresholding technique is used for image processing and analysis of the flank wear area. This strategy provides more information about drill wear conditions and should therefore have a higher reliability than previous methods. This study calulated quantitatively the flank were area of drill by computer program.

• Journal of International Society for Simulation Surgery
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• v.2 no.1
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• pp.33-39
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• 2015

Purpose The head of infants under 24 months old who has Craniosynostosis grows extraordinarily that makes head shape unusual. To diagnose the Craniosynostosis, surgeon has to inspect computed tomography(CT) images of the patient in person. It's very time consuming process. Moreover, without a surgeon, it's difficult to diagnose the Craniosynostosis. Therefore, we developed technique which detects Craniosynostosis automatically from the CT volume. Materials and Methods At first, rotation correction is performed to the 3D CT volume for detection of the Craniosynostosis. Then, cranial area is extracted using the iterative thresholding method we proposed. Lastly, we diagnose Craniosynostosis by analyzing centroid relationships of clusters of cranial bone which was divided by cranial suture. Results Using this automatical cranial detection technique, we can diagnose Craniosynostosis correctly. The proposed method resulted in 100% sensitivity and 90% specificity. The method perfectly diagnosed abnormal patients. Conclusion By plugging-in the software on CT machine, it will be able to warn the possibility of Craniosynostosis. It is expected that early treatment of Craniosynostosis would be possible with our proposed algorithm.