• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.248-254
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• 2015

In this paper we propose an improved version of the computational integral imaging reconstruction (CIIR) for visualizing a partially occluded object by utilizing an image inpainting technique. In the proposed method the elemental images for a partially occluded three-dimensional (3D) object are recorded through the integral imaging pickup process. Next, the depth of occlusion within the elemental images is estimated using two different CIIR methods, and the weight mask pattern for occlusion is generated. After that, we apply our image inpainting technique to the recorded elemental images to fill in the occluding area with reliable data, using information from neighboring pixels. Finally, the inpainted elemental images for the occluded region are reconstructed using the CIIR process. To verify the validity of the proposed system, we carry out preliminary experiments in which faces are the objects. The experimental results reveal that the proposed system can dramatically improve the quality of a reconstructed CIIR image.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.45-54
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• 1986

The establishment and/or registration of an optimal or physiologic relationship between the maxillae and mandible has long been a subject of considerable interest and controversy in dentistry. Centric relation has been generally accepted as a repeatable starting point for restoring the mouth. Recently, it has been claimed that an electronic device (Myo-Monitor) will produce an accurate, reproducible occlusal registration at the vertical and horizontal occlusal position most compatible with the muscular of each patient. The objectives of this study was to compare Myo-Monitor centric to centric relation at the points of reproducibility and anteroposterior, superoinferior position. A Vericheck instrument was employed for examining difference in the position and reproducibility of mandible reproduced by the various check bite records. For this study, 8 dental students and dentists who had no missing teeth and no difficulties of mandibular movement were selected. The following three different positions of the mandible were registered (a) centric relation manipulated by means of chin-point technique with Lucia-jig, (b) centric relation manipulated by means of bilateral technique, (c) Myocentric manipulated by Myo-Monitor. From this experiment, the following results were obtained. 1. Bilateral manipulated centric relation was more reproducible than Myocentric in anteroposterior and superoinferior position , but more reproducible than centric relation manipulated by means of chin point technique with Lucia-jig in anteroposoterior position. Centric relation manipulated by means of chin Point technique with Lucia-jig was more reproducible than Myocentric in right anteroposterior and superoinferior position. 2. Centric relation by means of chin point technique with Lucia-jig was posterior($2.16{\pm}0.78mm$) and superior($0.41{\pm}0.16mm$) to centric occlusion. Bilateral manipulated centric relation was posterior($1.68{\pm}0.10mm$) and superior($1.02{\pm}0.45mm$) to centric occlusion. Myocentric was anterior($0.75{\pm}0.70mm$), inferior($0.59{\pm}0.44mm$) to centric occlusion.

• Journal of Broadcast Engineering
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• v.2 no.2
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• pp.216-224
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• 1997

In this paper, we propose a depth information extraction method for intermediate image synthesis. As stereo matching method, MBS(Multiple-Baseline Stereo) method has been proposed, in which the matching accuracy increases by using the multiple camera, but there are some inherent problems such as computational complexity, boundary overreach(BO) in depth map, and occlusion. So, we propose the modified version of MBS so called Multi-Resolution MBS(MR-MBS). Moreover, we also propose an adaptive occlusion area processing technique to improve the accuracy of the depth information in occlusion area.

• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.390-396
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• 2015

We propose a partial occlusion removal method for computational integral imaging reconstruction (CIIR) based on the usage of the exemplar based inpainting technique. The proposed method is an improved version of the original linear inpainting based CIIR (LI-CIIR), which uses the inpainting technique to fill in the data missing region. The LI-CIIR shows good results for images which contain objects with smooth surfaces. However, if the object has a textured surface, the result of the LI-CIIR deteriorates, since the linear inpainting cannot recover the textured data in the data missing region well. In this work, we utilize the exemplar based inpainting to fill in the textured data in the data missing region. We call the proposed method the neighboring elemental image exemplar based inpainting (NEI-exemplar inpainting) method, since it uses sources from neighboring elemental images to fill in the data missing region. Furthermore, we also propose an automatic occluding region extraction method based on the use of the mutual constraint using depth estimation (MC-DE) and the level set based bimodal segmentation. Experimental results show the validity of the proposed system.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.567-580
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• 1999

Accurate reproduction of intraoral tissue is essential in the fabrication of fixed prosthesis. This selection of impression material and method is very important. In this study, vinyl polysiloxane type impression material $Panasil^{(R)}$ was used. Three impression methods ; one-step technique, individual tray technique, and individual tooth tray technique using the vinyl polysiloxane type bite registration material $Futar^{(R)}$ Occlusion, were used to take horizontal and vertical impression. Improved stone models were fabricated. The amount of occlusal surface discrepaneies, interabutment distance discrepancies, amount of marginal defect were evaluated with the $X-PLAN360d^{(R)}$ and photoscanning. The results were as follows. 1. There was no significant difference in occlusal surface according to the directions and techniques of impression taking. 2. There was no significant difference in interabutment distance discrepancies according to the directions and techniques of impression taking 3. There was no significant difference in marginal discrepancies according to the direction of impression taking but there was significant difference between one-step technique and individual tray technique, individual tooth tray technique (P<0.05). Taken together, these results suggest that individual tray technique and individual tooth tray technique are more accurate for impression taking than one-step technique.

• The Journal of Korean Academy of Prosthodontics
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• v.18 no.1
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• pp.73-86
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• 1980

Recently, the controversy continues as to whether maximum intercuspation of teeth should occur at the terminal hinge position(the condylar theory) or at the myo-co(the neuromuscular theory). There is also much controversy regarding the antero-posterior position of myo-co. The object of this study was to measure and compare with the positional relations of centric relation, centric occlusion and myo-co, and free-way space using Mandibular Kinesiograph and Myo-monitor in the 40 subjects without stomatognathic problems. Mandibular Kinesiograph(M.K.G.) was originally conceived as a research instrument to track mandibular movement and position. As its use in research progressed, its great diagnostic value became apparent in case by case. And Myo-monitor was developed as a means of applying the neuromuscular approach to occlusion. Thus the Myo-monitor technique is an intra-systemic approach to occlusal positioning using patient's own musculature, and Myo-monitor is used to relax the musculature by a light myopulse induced electronically. From this experiment, the following results were obtained. 1. The adaptive free-way space before muscle relaxation was an average of $1.6{\pm}60mm$, and the true free-way space after muscle relaxation using Myo-monitor was an average of $2.4{\pm}0.74mm$. 2. It took an average of $25{\pm}3.11$ minutes to relax the mandibular musculature by Myo-monitor and administration of 5mg. Diazepam and an average of $38{\pm}4.73$ minutes by Myo-monitor without administration of Diazepam. 3. Myo-co existed anterior to centric occlusion, with an average of $0.53{\pm}0.31$ mm, and centric relation existed posterior to centric occlusion, with an average of $0.57{\pm}0.58mm$ before muscle relaxation and with an average of $0.57{\pm}0.43mm$ after muscle relaxation. 4. Centric relation coincided with centric occlusion in 5 of 40 subjects(12.5%), and posterior to centric occlusion in the rest of cases (87.5%). 5. Myo-co existed anterior to centric occlusion in 38 of 40 subjects(95%), except 1 subject that coincided with centric occlusion and 1 subject that existed posterior to centric occlusion. 6. Myo-co and centric relation existed inferior to centric occlusion and the lateral displacement was various with individual difference. 7. The total displacement from centric occlusion to centric relation was an average of $0.74{\pm}0.64mm$ before muscle relaxation, and an average of $0.68{\pm}0.53mm$ after muscle relaxation, and the total displacement from centric occlusion to myo-co was an average of $1.07{\pm}0.58mm$.

• Journal of Korean Neurosurgical Society
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• v.46 no.1
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• pp.31-37
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• 2009

Objective : This study was performed to elucidate the technical and patient-specific risk factors for postoperative ischemia in patients undergoing temporary arterial occlusion (TAO) during the surgical repair of their aneurysms. Methods : Eighty-nine consecutive patients in whom TAO was performed during surgical repair of an aneurysm were retrospectively analyzed. The demographics of the patients were analyzed with respect to age. Hunt and Hess grade on admission, Fisher grade of hemorrhage, aneurysm characteristics, timing of surgery, duration of temporary occlusion, and number of temporary occlusive episodes. Outcome was analyzed at the 3-month follow-up, along with the occurrence of symptomatic and radiological stroke. Results : In overall, twenty-seven patients (29.3%) had radiologic ischemia attributable to TAO and fifteen patients (16.3%) had symptomatic ischemia attributable to TAO. Older age and poor clinical grade were associated with poor clinical outcome. There was a significantly higher rate of symptomatic ischemia in patients who underwent early surgery (p=0.007). The incidence of ischemia was significantly higher in patients with TAO longer than 10 minutes (p=0.01). In addition, patients who underwent repeated TAO, which allowed reperfusion, had a lower incidence of ischemia than those who underwent single TAO lasting for more than 10 minutes (p=0.011). Conclusion : Duration of occlusion is the only variable that needs to be considered when assessing the risk of postoperative ischemic complication in patients who undergo temporary vascular occlusion. Attention must be paid to the patient's age, grade of hemorrhage, and the timing of surgery. In addition, patients undergoing dissection when brief periods of temporary occlusion are performed may benefit more from intermittent reperfusion than continuous clip application. With careful planning, the use of TAO is a safe technique when used for periods of less than 10 minutes.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.783-790
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• 2011

Objectives : The purpose of this study was to examine students' difficulties in the process of oral radiography practice, to raise awareness of the importance and necessity of oral radiography and decipher, and to provide some information on effective ways of oral radiography practice. Methods : The subjects in this study were 285 dental hygiene students at K college, who included 153 sophomores and 132 graduates-to-be from June to November, 2010. Results : 1. The parts of the anatomy structure that they found it most difficult to decipher were maxillary molar(25.3%) and lower molar(22.1%). 2. They made during oral radiography was an improper film positioning(35.1%). 3. The part of bisecting technique was adjusting vertical and horizontal angles(53.0%). 4. The part of paralleling technique was positioning XCP in the oral cavity(44.2%). 5. The part of bite-wing technique was adjusting vertical and horizontal angles(38.2%). 6. The part of occlusion technique was positioning film and tube head(36.5%). 7. The part of panorama technique was finding out program setting(42.5%). Conclusions : The findings of the study indicated that in terms of anatomy structure decipher, it's especially difficult to decipher maxillary molar and lower molar, and that film positioning was difficult to do in the process of oral radiography. What difficulties they faced in applying each kind of oral radiography techniques and which part of the oral cavity they found it hard to radiograph were analyzed as well in this study. Given the findings of the study, more intensive practice is required to help students to acquire accurate oral radiography techniques to ensure their successful job performance in the future.

• Korean Journal of Bronchoesophagology
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• v.5 no.2
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• pp.202-206
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• 1999

A carotid artery resection and replacement including neck dissection are used as a method of treatment for head and neck cancer with infiltration into the carotid artery. The recent development of imaging technique makes it easy to estimate the detailed anatomical relationship between the tumor infiltration into the carotid artery, it's resection and replacement are indicated at radical neck dissection. To detect any possibility of cerebral ischemia at the time of ligation of carotid artery, a temporary occlusion test of internal carotid artery with a ballon catheter (balloon occlusion test) is performed. Recently, we performed a carotid artery resection and replacement using an artificial vessel Gore-Tex) in a case of neck cancer with infiltration into the carotid artery.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1745-1754
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• 2009

PTZ (Pan-Tilt-Zoom) camera based surveillance systems are enlarging their field of application due to their wide observable area. We aimed to detect both static and moving objects in automated working space by using a PTZ camera. For object detection we used background difference method because of the high quality segmentation. However, the method has a problem called 'hole' that is caused by non-continuous surveillance of the PTZ camera and its own characteristics. Moreover, the occlusion which occurs when the moving object overlaps with the static object should be solved for robust object detection. In this paper, we suggest a region-based technique for updating background images thereby overcoming the hole and occlusion problem. Through experiments with real scenes, it was verified that meaningful static and/or moving objects were detected very well.