• International Journal of Fuzzy Logic and Intelligent Systems
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• v.12 no.2
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• pp.137-142
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• 2012

The temporal subtraction technique as one of computer aided diagnosis has been introduced in medical fields to enhance the interval changes such as formation of new lesions and changes in existing abnormalities on deference image. With the temporal subtraction technique radiologists can easily detect lung nodules on visual screening. Until now, two-dimensional temporal subtraction imaging technique has been introduced for the clinical test. We have developed new temporal subtraction method to remove the subtraction artifacts which is caused by mis-registration on temporal subtraction images of lungs on MDCT images. In this paper, we propose a new computer aided diagnosis scheme for automatic enhancing the lung nodules from the temporal subtraction of thoracic MDCT images. At first, the candidates regions included nodules are detected by the multiple threshold technique in terms of the pixel value on the temporal subtraction images. Then, a rule-base method and artificial neural networks is utilized to remove the false positives of nodule candidates which is obtained temporal subtraction images. We have applied our detection of lung nodules to 30 thoracic MDCT image sets including lung nodules. With the detection method, satisfactory experimental results are obtained. Some experimental results are shown with discussion.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.454-456
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• 2002

The evaluation of interval changes between temporally sequential chest radiographs is necessary for the detection of new abnormalities or interval changes, such as pulmonary nodules and interstitial disease. For interstitial lung disease, the interval changes are very important for diagnosis and treatment. Especially, interstitial lung disease may show rapid changes in the radiographs, show changes in the entire lung field in minute detail, or show changes in multiple parts depending on the type. It is therefore difficult to have an accurate grasp of the condition of the disease only with conventional radiographs. The temporal subtraction technique which was developed at the University of Chicago, provides a subtraction image of the current warped image and the previous image. A temporal subtraction image, shows only differences and changes between the two images, can be very useful for a diagnosis of interstitial lung disease. However, the evaluation of the temporal subtraction technique for interstitial lung disease using receiver operating characteristic(ROC) studies has not been reported yet. Therefore, we have evaluated the clinical usefulness of a temporal subtraction technique for detection of interval changes of interstitial lung disease by ROC analysis.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.31-36
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• 2020

Most of the background subtraction algorithms show good performance in static scenes. In the case of dynamic scenes, they frequently cause false alarm to "temporal clutter", a repetitive motion within a certain area. In this paper, we propose a robust technique for the multiple interval pixel sampling (MIS) algorithm to handle highly dynamic scenes. An adaptive threshold scheme is used to suppress false alarms in low-confidence regions. We also utilize multiple background models in the foreground segmentation process to handle repetitive background movements. Experimental results revealed that our approach works well in handling various temporal clutters.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.335-337
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• 2002

The aim of this study was investigate the epileptogenic zone in temporal lobe epilepsy (TLE). We evaluated the subtraction image of interictal SPECT from ictal SPECT coregistered to 3-dimensional (3D) MRI, and compared with the normal healthy SPECT using a SPM99. Forty-nine patients with TLE (M:F=28:21, mean age: 33${\pm}$2.1 years) underwent a pairs of ictal and interictal SPECT. We performed subtraction interictal SPECT from ictal SPECT in TLE patients. In addition, using SPM methods and t-statistics, SPECT images of the TLE patients were compared with normal healthy SPECT on a voxel by voxel basis. The voxels with a p-value of less than 0.05, 0.005, 0.001 were considered to be significantly different. The subtraction results by ictal and interictal SPECT coincided with the significant rCBF changes when compare of the normal healthy SPECT using a SPM99. The results suggested that analysis of difference of the two methods using healthy normal SPECT with SPM99 is useful tool in evaluation of seizure focus in epilepsy.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.372-378
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• 2015

Background subtraction is the first processing stage in video surveillance. It is a general term for a process which aims to separate foreground objects from a background. The goal is to construct and maintain a statistical representation of the scene that the camera sees. The output of background subtraction will be an input to a higher-level process. Background subtraction under dynamic environment in the video sequences is one such complex task. It is an important research topic in image analysis and computer vision domains. This work deals background modeling based on modified adaptive Gaussian mixture model (GMM) with three temporal differencing (TTD) method in dynamic environment. The results of background subtraction on several sequences in various testing environments show that the proposed method is efficient and robust for the dynamic environment and achieves good accuracy.

• Archives of Craniofacial Surgery
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• v.11 no.1
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• pp.49-52
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• 2010

Posttraumatic pseudoaneurysm of the superficial temporal artery is very rare and occurs secondary to trauma. Clinical diagnosis is based on past history of trauma and physical examination and can be confirmed by duplex ultrasonogram, digital subtraction angiography, CT and MRI. Ligation of proximal and distal ends of the superficial temporal artery and excision of the pseudoaneurysm has been the standard treatment. Compressive therapy, endovascular coil embolization, percutaneous thrombin injection under ultrasound guidance have been reported as alternative treatment methods. When surgical excision of the superficial temporal artery pseudoaneurysm is performed, surgeon must be concerned about the anatomical relation between superficial temporal artery and temporal branches of the facial nerve. In this article, we report a rare case of superficial temporal artery pseudoaneurysm with some review of the literatures about anatomical relation between superficial temporal artery and temporal branches of facial nerve.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.9
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• pp.939-945
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• 2009

In this paper, we proposed a method which corresponds people under the structured spaces with multiple cameras. The correspondence takes an important role for using multiple camera system. For solving this correspondence, the proposed method consists of three main steps. Firstly, moving objects are detected by background subtraction using a multiple background model. The temporal difference is simultaneously used to reduce a noise in the temporal change. When more than two people are detected, those detected regions are divided into each label to represent an individual person. Secondly, the detected region is segmented as features for correspondence by a criterion with the color distribution and context information of human body. The segmented region is represented as a set of blobs. Each blob is described as Gaussian probability distribution, i.e., a person model is generated from the blobs as a Gaussian Mixture Model (GMM). Finally, a GMM of each person from a camera is matched with the model of other people from different cameras by maximum likelihood. From those results, we identify a same person in different view. The experiment was performed according to three scenarios and verified the performance in qualitative and quantitative results.

• The Korean Journal of Nuclear Medicine
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• v.32 no.1
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• pp.20-31
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• 1998

A robust algorithm to disclose and display the difference of ictal and interictal perfusion may facilitate the detection of ictal hyperfusion foci. Diagnostic performance of localizing epileptogenic zones with subtracted SPECT images was compared with the visual diagnosis using ictal and interictal SPECT, MR, or PET. Ietal and interictal Tc-99m-HMPAO cerebral perfusion SPECT images of 48 patients(pts) were processed to get parametric subtracted images. Epileptogenic foci of all pts were diagnosed by seizure free state after resection of epileptogenic zones. In subtraction SPECT, we used normalized difference ratio of pixel counts(ictal-interictal)/interictal ${\times}100%$) after correcting coordinates of ictal and interictal SPECT in semi-automatized 3-dimensional fashion. We found epileptogenic zones in subtraction SPECT and compared the performance with visual diagnosis of ictal and interictal SPECT, MR and PET using post-surgical diagnosis as gold standard. The concordance of subtraction SPECT and ictal-interictal SPECT was moderately good(kappa=0.49). The sensitivity of ictal-interictal SPECT was 73% and that of subtraction SPECT 58%. Positive predictive value of ictal-interictal SPECT was 76% and that of subtraction SPECT was 64%. There was no statistical difference between sensitivity or positive predictive values of subtraction SPECT and ictal-interictal SPECT, MR or PET. Such was also the case when we divided patients into temporal lobe epilepsy and neocortical epilepsy. We conclude that subtraction SPECT we produced had equivalent diagnostic performance compared with ictal-interictal SPECT in localizing epileptogenic zones. Additional value of these subtraction SPECT in clinical interpretation of ictal and interictal SPECT should be further evaluated.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.12-22
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• 2001

Purpose: The ictal perfusion patterns of cerebellum and basal ganglia have not been systematically investigated in patients with temporal lobe epilepsy (TLE). Their ictal perfusion patterns were analyzed in relation with temporal lobe and frontal lobe hyperperfusion during TLE seizures using SPECT subtraction. Materials and Methods: Thirty-three TLE patients had interictal and ictal SPECT, video-EEG monitoring, SPGR MRI, and SPECT subtraction with MRI co-registration. Results: The vermian cerebellar hyperperfusion (CH) was observed in 26 patients (78.8%) and hemispheric CH in 25 (75.8%). Compared to the side of epileptogenic temporal lobe, there were seven ipsilateral hemispheric CH (28.0%), fifteen contralateral hemispheric CH (60.0%) and three bilateral hemispheric CH (12.0%). CH was more frequently observed in patients with additional frontal hyperperfusion (14/15, 93.3%) than in patients without frontal hyperperfusion (11/18, 61.1%). The basal ganglia hyperperfusion (BGH) was seen in 11 of the 15 patients with frontotemporal hyperperfusion (73.3%) and 11 of the 18 with temporal hyperperfusion only (61.1%). In 17 patients with unilateral BGH, contralateral CH to the BGH was observed in 14 (82.5%) and ipsilateral CH to BGH in 2 (11.8%) and bilateral CH in 1 (5.9%). Conclusion: The cerebellar hyperperfusion and basal ganglia hyperperfusion during seizures of TLE can be contralateral, ipsilateral or bilateral to the seizure focus. The presence of additional frontal or basal ganglia hyperperfusion was more frequently associated with contralateral hemispheric CH to their sides. However, temporal lobe hyperperfusion appears to be related with both ipsilateral and contralateral hemispheric CH.

• Korean Journal of Remote Sensing
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• v.31 no.4
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• pp.321-330
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• 2015

Atmospheric correction is an essential part in time-series analysis on biophysical parameters of surface features. In this study, we tried to examine possible problems in atmospheric correction of multitemporal High Spatial Resolution (HSR) images obtained from two different sensor systems. Three KOMPSAT-2 and two IKONOS-2 multispectral images were used. Three atmospheric correction methods were applied to derive surface reflectance: (1) Radiative Transfer (RT) - based absolute atmospheric correction method, (2) the Dark Object Subtraction (DOS) method, and (3) the Cosine Of the Uun zeniTh angle (COST) method. Atmospheric correction results were evaluated by comparing spectral reflectance values extracted from invariant targets and vegetation cover types. In overall, multi-temporal reflectance from five images obtained from January to December did not show consistent pattern in invariant targets and did not follow a typical profile of vegetation growth in forests and rice field. The multi-temporal reflectance values were different by sensor type and atmospheric correction methods. The inconsistent atmospheric correction results from these multi-temporal HSR images may be explained by several factors including unstable radiometric calibration coefficients for each sensor and wide range of sun and sensor geometry with the off-nadir viewing HSR images.