• Journal of KIISE
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• v.43 no.4
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• pp.437-449
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• 2016

Previous image processing techniques based on plane-to-plane transformations cannot be utilized for spherical panoramic images. In this paper, we propose a new method to inpaint a spherical panoramic image using exemplar, which is deformed by the location of the patch. Our proposed method makes the deformed exemplar patch by latitude and uses it as the reference patch to restore the damaged area. The exemplar-based inpainting method is based on the planar image coordinate system and thus the classical method cannot be applied to the spherical panoramic image. The merit of our proposed method is the fact that it is not dependent on the location of the damaged area. From the experimental results, we proved that our proposed method satisfies the original purpose of the exemplar-based inpainting technique for the spherical panoramic image.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.543-548
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• 2017

$360^{\circ}$panoramic image can give people an unprecedented visual experience, and there are many different ways to make a $360^{\circ}$panoramic image. In this paper, we will introduce two easy and effective methods from those many ways. The first one is through 48 photos to make a $360^{\circ}$panoramic image, the second way is through 6 photos to make a $360^{\circ}$panoramic image. We will compare those methods and tell the audience which one suits themselves. Through those easy design methods introduced above, we can see VR works design became easy and popular, normal people can also make $360^{\circ}$panoramic image, and it promotes the industry of VR image contents.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.389-398
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• 1995

The purpose of this study was to compare the diagnostic performance of Waters' and panoramic view; maxillary sinus posteroanterior and lateral scanography of Scanora/sup (R)/ for mucosal thickening of maxillary sinus as well as to identify the utility of Scanora/sup (R)/ for the detection of maxillary sinus disease. The assessment was done at 66 maxillary sinuses in 45 patients and the results were as follows ; 1. Estimation of presence or absence of mucosal thickening. The sensitivity, specificity, and positive and negative predictive value of maxillary sinus posteroanterior and lateral scanography were 0.865, 0.860, 0.921, and 0.805 respectively and slightly higher than those of Waters' and panoramic views, which were 0.832, 0.835, 0.903, and 0.728 respectively. However, paired t-test showed no significant differences in the diagnostic performance of the two pairs of imaging modalities. 2. Estimation of the types of mucosal thickening. The diagnostic accuracy for type I, II, III was 75.3％ on Waters' and panoramic view; 77.9％ on maxillary sinus posteroanterior and lateral scanography. It was higher on the latter ,but showed no significant differences from that on the former. 3. Reliability of interpretation. In itraobserver and interobserver agreement, both overall rates of agreement and kappa-value were slightly higher on maxillary sinus posteroanterior and lateral scanography than on Waters' and panoramic views. There was no significant differences between the two pairs of imaging modalities. These results suggested that scanogram is a useful diagnostic radiography as well as Waters' and panoramic views for detection of maxillary sinusitis.

• Imaging Science in Dentistry
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• v.33 no.1
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• pp.35-41
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• 2003

Purpose: To aid in determining the volume of graft bone required before a maxillary sinus lift procedure and compare the alveolar bone height measurements taken by panoramic radiographs to those by CT images. Materials and Methods : Data obtained by both panoramic radiographs and CT examination of 25 patients were used in this study. Maxillary sinus volumes from the antral floor to heights of 5 mm, 10 mm, 15 mm, and 20 mm, were calculated. Alveolar bone height was measured on the panoramic images at each maxillary tooth site and corrected by magnification rate (PBH). Available bone height (ABH) and full bone height (FBH) was measured on reconstructed CT images. PBH was compared with ABH and FBH at the maxillary incisors, canines, premolars, and molars. Results: Volumes of the inferior portion of the sinuses were 0.55 ± 0041 ㎤ for 5 mm lifts, 2.11 ± 0.68 ㎤ for 10 mm, 4.26 ± 1.32 ㎤ for 15 mm, 6.95 ± 2.01 ㎤ for 20 mm. For the alveolar bone measurement, measurements by panoramic images were longer than available bone heights determined by CT images at the incisor and canine areas, and shorter than full bone heights on CT images at incisor, premolar, and molar areas (p<0.001). Conclusion: In bone grafting of the maxillary sinus floor, 0.96 ㎤ or more is required for a 5 mm-lift, 2.79 ㎤ or more for a 10 mm-lift, 5.58 ㎤ or more for a 15 mm-lift, and 8.96 ㎤ or more for a 20 mm-lift. Maxillary implant length determined using panoramic radiograph alone could result in underestimation or overestimation, according to the site involved.

• Imaging Science in Dentistry
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• v.42 no.4
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• pp.207-212
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• 2012

Purpose: This study was performed to determine the relative frequency of positioning errors, to identify those errors directly responsible for diagnostically inadequate images, and to assess the quality of panoramic radiographs in a sample of records collected from a dental college. Materials and Methods: This study consisted of 1,782 panoramic radiographs obtained from the Department of Oral and Maxillofacial Radiology. The positioning errors of the radiographs were assessed and categorized into nine groups: the chin tipped high, chin tipped low, a slumped position, the patient positioned forward, the patient positioned backward, failure to position the tongue against the palate, patient movement during exposure, the head tilted, and the head turned to one side. The quality of the radiographs was further judged as being 'excellent', 'diagnostically acceptable', or 'unacceptable'. Results: Out of 1,782 radiographs, 196 (11%) were error free and 1,586 (89%) were present with positioning errors. The most common error observed was the failure to position the tongue against the palate (55.7%) and the least commonly experienced error was patient movement during exposure (1.6%). Only 11% of the radiographs were excellent, 64.1% were diagnostically acceptable, and 24.9% were unacceptable. Conclusion: The positioning errors found on panoramic radiographs were relatively common in our study. The quality of panoramic radiographs could be improved by careful attention to patient positioning.

• Imaging Science in Dentistry
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• v.45 no.3
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• pp.175-180
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• 2015

Purpose: This study was performed to evaluate the reliability of the identification of anatomical landmarks in panoramic and lateral cephalometric radiographs on a standard medical grade picture archiving communication system (PACS) monitor and a tablet computer (iPad 5). Materials and Methods: A total of 1000 radiographs, including 500 panoramic and 500 lateral cephalometric radiographs, were retrieved from the de-identified dataset of the archive of the Section of Oral and Maxillofacial Radiology of the University Of Connecticut School Of Dental Medicine. Major radiographic anatomical landmarks were independently reviewed by two examiners on both displays. The examiners initially reviewed ten panoramic and ten lateral cephalometric radiographs using each imaging system, in order to verify interoperator agreement in landmark identification. The images were scored on a four-point scale reflecting the diagnostic image quality and exposure level of the images. Results: Statistical analysis showed no significant difference between the two displays regarding the visibility and clarity of the landmarks in either the panoramic or cephalometric radiographs. Conclusion: Tablet computers can reliably show anatomical landmarks in panoramic and lateral cephalometric radiographs.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.757-764
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• 2013

A panoramic video which supports to make viewers feel an immersion through fitting to a wide field of view (FOV) larger than the human visual angle needs an interactive viewing method such as selecting targeted view point among widely viewing points of a panoramic video because it difficult to simultaneously view a whole panoramic video due to a limited viewing environment and bandwidth. When a user officially uses a view navigation in order to select a view point, it happens waste of resources such as bandwidth owing to the transmitted video data of unnecessary view points. Therefore, this paper proposes the spatial-temporal prediction filter (STPF) which is based on the direction and velocity of the view navigation for transmitting only the necessary video data. As a result of simulation, STPF reduces bitrate saving rates by from 6% to 37% compared to conventional methods in the interactive panoramic video streaming service required high bandwidth.

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.223-235
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• 2021

Purpose: This study aimed to summarize the impact of neck and head radiation treatment on maxillofacial structures detected on panoramic radiographs. Materials and Methods: In this systematic review, the authors searched PubMed Central, Embase, Scopus, Cochrane Central Register of Controlled Trials, Web of Science, and Google Scholar for original research studies up to February 2020 that included the following Medical Subject Headings keywords: words related to "radiotherapy" and synonyms combined with keywords related to "panoramic radiography" and "oral diagnosis" and synonyms. Only original studies in English that investigated the maxillofacial effects of radiotherapy via panoramic radiographs were included. The quality of the selected manuscripts was evaluated by assessing the risk of bias using Cochrane's ROBINS-I tool for non-randomized studies. Results: Thirty-three studies were eligible and included in this review. The main objectives pertained to the assessment of the effects of radiation on maxillofacial structures, including bone architecture alterations, periodontal space widening, teeth development abnormalities, osteoradionecrosis, and implant bone loss. The number of participants evaluated ranged from 8 to 176. Conclusion: The interaction between ionizing radiation and maxillofacial structures results in hazard to the tissues involved, particularly the bone tissue, periosteum, connective tissue of the mucosa, and endothelium. Hard tissue changes due to radiation therapy can be detected on panoramic radiographs.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1377-1384
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• 2018

Accurate measurement of the absorbed dose and the effective dose is required in dental panoramic radiography involving relatively low energy with a rotational X-ray tube system using long exposures. To determine the effectiveness of measuring the irradiation by using passive dosimetry, we compared the entrance skin doses by using a radiophotoluminescent glass dosimeter (RPL) and an optically stimulated luminescence detector (OSL) in a phantom model consisting of nine and 31 transverse sections. The parameters of the panoramic device were set to 80 kV, 4 mA, and 12 s in the standard program mode. The X-ray spectrum was applied in the same manner as the panoramic dose by using the SpekCalc Software. The results indicated a mass attenuation coefficient of $0.008226cm^2/g$, and an effective energy of 34 keV. The equivalent dose between the RPL and the OSL was calculated based on a product of the absorbed doses. The density of the aluminum attenuators was $2.699g/cm^3$. During the panoramic examination, tissue absorption doses with regard to the RPL were a surface dose of $75.33{\mu}Gy$ and a depth dose of $71.77{\mu}Gy$, those with regard to the OSL were surface dose of $9.2{\mu}Gy$ a depth dose of $70.39{\mu}Gy$ and a mean dose of $74.79{\mu}Gy$. The effective dose based on the International Commission on Radiological Protection Publication 103 tissue weighting factor for the RPL were $0.742{\mu}Sv$, $8.9{\mu}Sv$, $2.96{\mu}Sv$ and those for the OSL were $0.754{\mu}Sv$, $9.05{\mu}Sv$, and $3.018{\mu}Sv$ in the parotid and sublingual glands, orbit, and thyroid gland, respectively. The RPL was more effective than the OSL for measuring the absorbed radiation dose in low-energy systems with a rotational X-ray tube.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.9-16
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• 2021

Purpose: The purpose of this study was to analyze the reliability of 7 panoramic radiographic signs for predicting proximity of the root apices of mandibular third molars to the mandibular canal using cone-beam computed tomography and to correlate these findings with the Pell and Gregory and the Winter classification systems. Materials and Methods: An observational, cross-sectional, descriptive study was conducted on 74 patients with bilateral impacted mandibular third molars. Four panoramic radiographic signs were observed in the tooth root (darkening, deflection, and narrowing of the root apices, and bifid apices), and another 3 in the mandibular canal (diversion, narrowing, and interruption of the mandibular canal). Cone-beam computed tomography images were analyzed to identify disruption and diversion of the mandibular canal and root deflection. Results: Binary logistic regression showed that only 4 of the 7 panoramic radiographic signs were able to predict proximity of the root apices of the mandibular third molars to the mandibular canal: darkening of the root, deflection of the root, narrowing of the root, and interruption of the mandibular canal(P<0.05). Conclusion: Darkening, deflection, and narrowing of the root, in tandem with the interruption of the mandibular canal on panoramic radiographs, indicate that cone-beam computed tomography should be performed when planning the extraction of impacted mandibular third molars. Proximity between mandibular third molars and the mandibular canal is correlated with the Winter classification.