• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.2
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• pp.207-211
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• 1993

The auther has evaluated the panoramic image of the mandibular condyle according to its horizontal codylar angle(0°, 10°, 20°, 30°, 40°) and intercondylar distance( 9.5, 11.0, 12.5, 14.0㎝). The Results were as follows: 1. In all horizontal condylar angle, the farther the intercondylar distance was, the smaller the horizontal length in radiogram was. 2. The increased the horizontal condylar angle was, the longer in horizontal direction and the shorter in vertical direction the image of superior condylar surface was. 3. In case of large horizontal condylar angle, the real mesial surface of condyle was projected to the posterior surface on radiograph.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.161-166
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• 2011

This paper addresses the vision based autonomous walking control system. To handle the obstacles which exist beyond the field of view(FOV), we used the 3d panoramic depth image. Moreover, to decide the avoidance direction and walking motion of a humanoid robot for the obstacle avoidance by itself, we proposed the vision based path planning using 3d panoramic depth image. In the vision based path planning, the path and walking motion are decided under environment condition such as the size of obstacle and available avoidance space. The vision based path planning is applied to a humanoid robot, URIA. The results from these evaluations show that the proposed method can be effectively applied to decide the avoidance direction and the walking motion of a practical humanoid robot.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.26 no.2
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• pp.191-200
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• 1996

This study was performed to determine the adequate resolution and compression method in teleradiology. A digital imaging system using Machintosh IT ci computer, 15' Sony high resolution RGB monitor, Umax Power look flatbed scanner with transparency unit and 12 panoramic radiographs were used. The results were as follows : 1. Relative detectability at the group scanned by 30ddpi, 600dpi and 1200dpi was same as those at the real panoramic radiographs. 2. Perceivable image quality degradation was found at the 25％ of middle quality of JPEG compression. But those were not diagnostically significant. 3. Perceivable image quality degradation was found at the 100％ of low quality of JPEG compression. And 8cases among them were diagnostically significant. On the basis of the above results, it is considered that the adequate resolution in scanning radiographs for teleradiology is 300dpi and compression method is the middle quality of JPEG compression.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.45-45
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• 2004

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.5
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• pp.464-473
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• 2006

Purpose: This study was performed to evaluate relationship between the inferior alveolar nerve injury and the findings of panoramic and tomographic images for preventing inferior alveolar nerve injury after the 3rd molar extraction. Material and Method: From April, 2005 to June, 2005, The 190 patients who visited in the Department of Oral and Maxillofacia Surgery, Chonnam National University Hospital and the panoramic radiographies were taken for extraction of the mandibular third molar, was selected. Among 215 mandibular third molars, Scanora tomographic imagings were taken in the 90 teeth which were overlaped to the mandibular canal in the panoramic imagies. In panoramic radiographies, the angulation, the level, the root morphology, and the superimposition sign of the mandibular third molars with the mandibular canal were evaluated. In the tomographic radiographies, the location and distance of the mandibular third molar from the canal were also evaluated. The relationships between these findings and the inferior alveolar nerve injury were examined. Results: In the panoramic findings, the inferior alveolar nerve injuries were occurred in the darkened roots (5 molars, 7%), the uncontinuous radiopaque image (3 molars, 7%), and the depositioned mandibular canal (2 molars, 10%). In the tomographic findings of 90 molars, 20 molars also had the superimposition imagies. Five molars in those molars (25%) had the inferior alveolar nerve injury after extraction. There were 10 patients who had the inferior alveolar nerve injury. The sensory was began to be recovered in 9 patients, except 1 patient, within 2 weeks, then fully recovered within 3 months. Conclusion: These results indicate that the depth mandibular third molar and the superimposition sign may be related with the risk of the inferior alveolar nerve injury after extraction.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.149-161
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• 2005

Catadioptric mirrors are widely used in automatic surveillance system. The major drawback of catadioptric mirror is its unequal image resolution. Equidistance catadioptric mirror can be the solution to this problem. Even double panoramic structure can generate stereo images with single camera system. So two images obtained from double panoramic equidistance catadioptric mirror can be used in finding the depth and height values of object's points. But compared to the single catadioptric mirror. the image size of double panoramic system is relatively small. This leads to the severe accuracy problem in estimation. The exact axial alignment and the exact mount of mirror are the sources that can be avoided but the focal length variation is inevitable. In this paper, the effects of focal length variation on the computation of depth and height of object' point are explained and the effective focal length finding algorithm, using the assumption that the object's viewing angles are almost same in stereo images, is presented.

• Imaging Science in Dentistry
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• v.43 no.1
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• pp.7-15
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• 2013

Purpose: This study was performed to suggest reference line-pair values of panoramic images with clinically desirable qualities using an arch-form phantom stand. Materials and Methods: The line-pair test phantom was chosen. A real skull model was selected for setting the arch-form model of the phantom stand. The phantom stand had slits in four regions (incisor, premolar, molar, TMJ). Four raw images of the test phantom in each region and one raw image of the real skull were converted into 50 test phantom images and 50 skull phantom images with various line-pair values. 50 post-processed real skull phantom images were divided into 4 groups and were randomly submitted to 14 evaluators. Image quality was graded on a 4 point scale (1. good, 2. normal, 3. poor but interpretable, and 4. not interpretable). The reference line pair was determined as the first line-pair value scored less than 2 points. Result: The mean scores tended to decrease as the line-pair values increased. The reference line-pair values were 3.19 LP/mm in the incisor, 2.32 LP/mm in the premolar and TMJ, and 1.88 LP/mm in the molar region. Conclusion: Image quality evaluation methods and criteria should be able to assess various regions considering the characteristics of panoramic systems. This study suggested overall and regional reference line-pair values and established a set of standard values for them.

• Imaging Science in Dentistry
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• v.32 no.1
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• pp.35-39
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• 2002

Purpose: The altered gantry angle during scanning for some multiplanar reconstruction CT program (CT/MPR) may cause distortion of the image. The aim of this study was to ascertain whether there is a image distortion in a reformatted image when the gantry and the object are equally inclined using ToothPix and DentaScan program. Materials and Methods: A resin block model with four cylindrical holes and a human dry mandible were used. Two MPR software packages, ToothPix and DentaScan program, were used for reformatted panoramic images. The block and the gantry were equally inclined at 0°, 15°, and 30°. Results: With ToothPix program, a resin block model with empty holes and a dry mandible showed inclined images in the reformatted panoramic image. Increasing the gantry angle, the depth and inclination of the holes were increased in the reformatted central panoramic images. However, a resin block model with gutta perch a in its holes and a dry mandible with a wire in its mandibular canal didn't show image distortion. With DentaScan program, image distortion was not seen in any situation. Conclusion: ToothPix program may distort the reformatted image when the gantry angle is not at zero degrees. However, with DentaScan program, the patient may be positioned comfortably and the gantry can be adjusted to the patient positioning.

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.11-15
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• 2000

Purpose: The primary objective of this study was to estimate the radiation absorbed doses in certain critical organs in the head and neck region with an Orthopos plus, a Panelipse, and a Panex-E machines. The second objective was to compare the absorbed doses between 5 inch by 12 inch and 6 inch by 12 inch image field for the Orthopos plus. Materials and Methods: Rando phantom and LiF TLD chips were used for dosimetry. The absorbed doses were measured at the thyroid gland, the submandibular gland, the parotid gland, the mouth floor, the maxillary sinus, the brain, the mandibular body, the mandibular ramus, the 2nd cervical spine and the skin over TMJ area. Results: The highest absorbed dose value was recorded at the mandibular ramus for the Orthopos plus with narrow image field. Higher absorbed dose values were recorded at the parotid gland, the mouth floor, the submandibular gland, and the 2nd cervical spine. The doses in the parotid gland were 597 μGy and 529 μGy with Orthopos plus, 638 μGy with Panelipse, and 1094μGy with Panex-E. Corresponding figures for the mandibular ramus were 2363 Gy and 1220 μGy, 248 μGy, and 118 μGy. The absorbed doses to the thyroid gland, the maxillary sinus, the brain, and the skin over TMJ were very low. Conclusion: Higher exposure values were recorded for the Orthopos plus than Panelipse and Panex-E. There was no significant differences of the absorbed doses according to the image field size.

• Journal of Broadcast Engineering
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• v.6 no.2
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• pp.160-168
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• 2001

In this paper, we propose a new practical motion model that can exploit the general properties of camera motion in constructing a panorama. accounting for panning. tilting, and evert the change in focal length of the camera. We also present an efficient algorithm to handle moving objects or noose in the scene based on outliers rejection. Spatial and temporal statistical properties of motion field are exploited to detect the outliers. The proposed algorithm removes moving objects or noise from the panoramic Image so that mode clear and complete view of the background Image can be obtained. This method does not require assumptions or a priors knowledge of the scene. The entire process is fully automatic as this method does not require any manual correction in the process of constructing a Panorama. The proposed algorithm is tested on the broadcasting images of soccer games. Oun simulation result shows that this method is superior to conventional image mosaicing algorithms.