• Journal of Korea Multimedia Society
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• v.19 no.3
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• pp.626-632
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• 2016

In this paper, we propose the defect emphasis in TFT-LCD panel image. The defect emphasis image consist of S(Shape) map and B(Brightness) map. S map based on DoG(difference of gaussian) is made with the mura defect shape characteristic. And B map use defect intensity property that defect intensity is higher than background. The experiments were conducted to evaluate the performance of the proposed defect emphasis method. The results of experiments show the validity of the defect emphasis using the proposed method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.1-12
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• 2023

To make semiconductor chips, a number of complex semiconductor manufacturing processes are required. Semiconductor chips that have undergone complex processes are subjected to EDS(Electrical Die Sorting) tests to check product quality, and a wafer bin map reflecting the information about the normal and defective chips is created. Defective chips found in the wafer bin map form various patterns, which are called defective patterns, and the defective patterns are a very important clue in determining the cause of defects in the process and design of semiconductors. Therefore, it is desired to automatically and quickly detect defective patterns in the field, and various methods have been proposed to detect defective patterns. Existing methods have considered simple, complex, and new defect patterns, but they had the disadvantage of being unable to provide field engineers the evidence of classification results through deep learning. It is necessary to supplement this and provide detailed information on the size, location, and patterns of the defects. In this paper, we propose an anomaly detection framework that can be explained through FCDD(Fully Convolutional Data Description) trained only with normal data to provide field engineers with details such as detection results of abnormal defect patterns, defect size, and location of defect patterns on wafer bin map. The results are analyzed using open dataset, providing prominent results of the proposed anomaly detection framework.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.116-123
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• 2003

Purpose : The present study was undertaken to evaluate the usefulness of cerebral diffusion (DWI) and perfusion MR imaging (PWI) in rabbit models with hyperacute cerebral ischemic infarction. Materials and Methods : Experimental cerebral infarction were induced by direct injection of mixture of Histoacryl glue, lipiodol, and tungsten powder into the internal cerebral artery of 6 New-Zealand white rabbits, and they underwent conventional T1 and T2 weighted MR imaging, DWI, and PWI within 1 hour after the occlusion of internal cerebral artery. The PWI scan for each rabbit was obtained at the level of lateral ventricle and 1cm cranial to the basal ganglia. By postprocessing using special imaging software, perfusion images including cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps were obtained. The detection of infarcted lesion were evaluated on both perfusion maps and DWI. MTT difference time were measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Results : In all rabbits, there was no abnormal signal intensity on T2WI. But on DWI, abnormal high signal intensity, suggesting cerebral infarction, were detected in all rabbits. PWI (rCBV, CBF and MTT map) also showed perfusion defect in all rabbits. In four rabbits, the calculated square of perfusion defect in MTT map is larger than that of CBF map and in two rabbits, the calculated size of perfusion defect in MTT map and CBF map is same. Any rabbits do not show larger perfusion defect on CBF map than MTT map. In comparison between CBF map and DWI, 3 rabbits show larger square of lesion on CBF map than on DWI. The others shows same square of lesion on both technique. The size of lesion shown in 6 MTT map were larger than DWI. In three cases, the size of lesion shown in CBF map is equal to DWI. But these were smaller than MTT map. The calculated square of lesion in CBF map, equal to that of DWI and smaller than MTT map was three. And in one case, the calculated square of perfusion defect in MTT map was largest, and that of DWI was smallest. Conclusion : DWI and PWI may be useful in diagnosing hyperacute cerebral ischemic infarction and in e-valuating the cerebral hemodynamics in the rabbits.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.369-377
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• 2023

In the industrial manufacturing sector, quality control is pivotal for minimizing defect rates; inadequate management can result in additional costs and production delays. This study underscores the significance of detecting texture defects in manufactured goods and proposes a more precise defect detection technique. While the DFR(Deep Feature Reconstruction) model adopted an approach based on feature map amalgamation and reconstruction, it had inherent limitations. Consequently, we incorporated a new loss function using statistical methodologies, integrated a skip connection structure, and conducted parameter tuning to overcome constraints. When this enhanced model was applied to the texture category of the MVTec-AD dataset, it recorded a 2.3% higher Defect Segmentation AUC compared to previous methods, and the overall defect detection performance was improved. These findings attest to the significant contribution of the proposed method in defect detection through the reconstruction of feature map combinations.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.25-31
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• 2003

This study was performed to evaluate the usefulness of Deconvolution perfusion CT in patients with acute cerebral infarction. Nine patients with acute cerebral infarction underwent conventional CT and cerebral perfusion CT within 23 hours of the onset of symptoms. The perfusion CT scan for each patient was obtained at the levels of basal ganglia and 1cm caudal to the basal ganglia. By special imaging software, perfusion images including cerebral blood volume(CBV), cerebral blood flow(CBF), and mean transit time(MTT) maps were created. The created lesions were evaluated on each perfusion maps by 3 radiolocical technician. MTT delay time was measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Lesion sire were measured on each perfusion map and compared with the value obtained by diffusion weighted MR imaging(DWMRI). All perfusion CT maps showed the perfusion defect lesion in all patients. There were remarkable CT delay in perfusion defect lesion. In comparison of lesion size between each perfusion map and DWMRI, the lesion on CBF map was the most closely correlated with the lesion on DWMRI(7/9). The size of perfusion defect lesion on MTT map was larger than that of lesion on DWMRI, suggesting that m map can evaluate the ischemic penumbra. Deconvolution Perfusion CT maps make it possible to evaluate not only ischemic core and ischemic penumbra but also hemodynamic status in perfusion defect area. These results demonstrate that perfusion CT can be useful to the diagnosis and treatment in the patients with acute cerebral ischemic infarction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.533-536
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• 2005

MAP algorithm is known for optimal decoding algorithm of Turbo codes, but it has very large computational complexity and delay. Generally log-MAP algorithm is used in order to overcome the defect. In this paper we propose modified scheme of the state metric calculation block which can improve the computation speed in log-MAP decoder and simple linear offset unit without using LUT. The simulation results show that the operation speed of the proposed scheme is improved as compared with that of the past scheme.

• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.19-26
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• 2012

It is very important for early diagnosis and therapy with ischamic cerebral infarction patients. This study was to know the ischemic penumbra lesion which compared CT-perfusion and diffusion weighted MRI(DWMRI) with acute cerebral infarction patients. 12 acute cerebral infarction patients had performed perfusion CT and performed DWMRI. Perfusion images including cerebral blood volume(CBV), cerebral blood flow(CBF), time to peak(TTP) and mean transit time(MTT) maps obtained the values with defect lesion and contralateral normal cerebral hemisphere and DWMRI was measured by signal intensity and compared of lesion size between each perfusion map. All perfusion CT maps showed the perfusion defect lesions in all patients. There were remarkable TTP and MTT delay in perfusion defect lesions. The lesions on CBF map was the most closely correlated with the lesions on DWMRI. The size of perfusion defect lesions on TTP and MTT map was larger than that of lesions on DWMRI, suggesting that MTT map can evaluate the ischemic penumbra. Perfusion CT maps make it possible to evaluate not only ischemic core and ischemic penumbra, but also hemodynamic status in the perfusion defect area. These results demonstrate that perfusion CT can be useful to the diagnosis and treatment in the patients with acute cerebral ischemic infarction.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.51-58
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• 1993

We have anlayzed the polar maps of dipyridamole stress/rest $^{99m}Tc$-MIBI SPECT and compared the quantitated perfusion defects of dipyridamole stress polar map and the findings of coronary angiography in 56 pateints with coronary artery diseases. We performed the same day dipyridamole stress-rest myocardial SPECT, reconstructed the polar maps according to Cedars-Sinai method and quantitated perfusion detects of total myocardium and the territory of each artery, comparing the polar maps of patients with normal files. Stenosis more than 50 percent was considered significant and myocardial ischemic score was calculated as summed score of percents of main coronary arteries. Positive concordance of myocardial SPECT with coronary angiography were 82.6% with left anterior descending artery (LAD), 85.7% with left circumflex artery (LCx) and 78.6% with right coronary artery (RCA). Perfusion defect of SPECT polar map and the stenosis of coronary artery showed the contingency phi of 0.55 (p<0.0001) with total atreries, 0.38 (p = 0.016) with LAD, 0.50 (p<0.0001) with LCx and 0.40 (p = 0.007) with RCA. Dipyridamole stress percent defect of polar map was correlated with myocardial ischemic score with Spearman's rho of 0.47 (p = 0.001) in total arteries, 0.48 (p=0.001) in LAD, 0.56 (p < 0.001) in LCx and 0.38 (p=0.002) in RCA. These findings revealed that defect of the dipyridamole stress myocardial $^{99m}Tc$-MIBI SPECT and the percent extent of this defect were related with significant artery stenosis of individual arteries and the degree of stenosis. We thought that we could use the defects in the polar map of dipyridamole stress $^{99m}Tc$-MIBI SPECT for the quantification of myocardiasl perfusion decrease.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1759-1766
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• 2001

Vibration transient generated by developing localized fault in gear can be used as indicators in gear fault detection. In this paper, we propose the zoomed phase map for a fault signal using continuous wavelet transfers to detect this vibration transient. Local fault induces the abrupt fluctuation of load exciting tooth and phase lag in the vibration signal measured on the gearbox. The relatively large fault like "tip breakage" easily can be detected by the clear fluctuation of exciting load. However, minor fault like "initial pitting"cannot be detected using the load fluctuation. To defect this kind of minor fault, the phase map for a fault signal is taken into account. The phase lag by minor fault is observed well in the zoomed phase map.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.177-184
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• 2012

An optical defect detection method using ESPI(electronic speckle pattern interferometry) is proposed. ESPI is widely used as a non-contact measurement system which show deformation and phase map in real time. ESPI can be divided as the in-plane, out-of-plane and shearography by operation principle and target object and also divided with bulk type and optic fiber type by the optic configurations. This paper is focused on optic fiber type out-of-plane ESPI, which has the following advantages: (1) low cost; (2) reduction of the unreliable factors generated by separated optic components; (3) simplification of the optic configuration; (4) great reduction of volume; (5) flexibility, to be easily designed into different structures to adapt to inaccessible environments such as pipeline cavity and so on.