• Journal of Periodontal and Implant Science
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• 제32권1호
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• pp.199-211
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• 2002

Digital substraction technique and computer-assisted densitometirc analysis detect minor change in bone density and thus increase the diagnostic accuracy. This advantage as well as high sensitivity and objectivity which precludes human bias have drawn interest in radiologic research area. The objectives of this study are to verify if Radiographic density can be recognized in linear pattern when density profile of standard periapical radiograph with the aluminium stepwedge as the reference, was investigated under varies circumstances which can be encountered in clinical situations, and in addition to that to obtain mutual relationship between the existing standard radiographic system, and future digital image systems, by confirming the corelationship between the standard radiograph and Digora system which is a digital image system currently being used. In order to make quantitative analysis of the bone tissue, digital image system which uses high resolution automatic slide scanner as an input device, and Digora system were compared and analyzed using multifunctional program, Brain3dsp. The following conclusions were obtained. 1. Under common clinical situation that is 70kVp, 0.2 sec., and focal distance 10cm, Al-Equivalent image equation was found to be Y=11.21X+46.62 $r^2=0.9898$ in standard radiographic system, and Y=12.68X+74.59, $r^2=0.9528$ in Digora system, and linear relation was confirmed in both the systems. 2. In standard radiographic system, when all conditions were maintained the same except for the condition of developing solution, Al-Equivalent image equation was Y=10.07X+41.64, $r^2=0.9861$ which shows high corelationship. 3. When all conditions were maintained the same except for the Kilovoltage peak, linear relationship was still maintained under 60kVp, and Al-Equivalent image equation was Y=14.60X+68.86, $r^2=0.9886$ in the standard radiograhic system, and Y=13.90X+80.68, $r^2=0.9238$ in Digora system. 4. When all conditions were maintained the same except for the exposure time which was varied from 0.01 sec. to 0.8 sec., Al-Equivalent image equation was found to be linear in both the standard radiographic system and Digora system. The R-square was distributed from 0.9188 to 0.9900, and in general, standard radiographic system showed higher R-square than Digora system. 5. When all conditions were maintained the same except for the focal distance which was varied from 5cm to 30cm, Al-Equivalent image equation was found to be linear in both the standard radiographic system and Digora system. The R-square was distributed from 0.9463 to 0.9925, and the standard radiographic system had the tendency to show higher R-square in shorter focal distances.

• 한국임상수의학회지
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• 제24권4호
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• pp.568-572
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• 2007

This study was carried out to show at the fractal analysis complements the practical disadvantage of gray level histogram which is designed to measure the quantitative classification of echo patterns in ultrasonographic image of parenchymal organs such as spleen and kidney and it is a practical method of measurement for quantitative classification. By using ultrasonographs, kidney and spleen of 21 healthy Beagles were fixed under different gain settings to be scanned for echo patterns and results were analyzed with body gray level histogram and fractal analysis. Then it was compared based on the statistical data obtained. Although there was a proportionate increase in histogram along with gain settings, there were consistencies in the fractal dimension. In terms of quantitative analysis in ultrasonographic images, fractal analysis is concluded to complement the practical disadvantage of gray level histogram.

• Imaging Science in Dentistry
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• 제53권2호
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• pp.109-115
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• 2023

Purpose: The aim of this study was to evaluate changes in the trabecular bone through texture analysis and compare the texture analysis characteristics of different areas in patients with medication-related osteonecrosis of the jaw (MRONJ). Materials and Methods: Cone-beam computed tomographic images of 16 patients diagnosed with MRONJ were used. In sagittal images, 3 regions were chosen: active osteonecrosis(AO); intermediate tissue (IT), which presented a zone of apparently healthy tissue adjacent to the AO area; and healthy bone tissue (HT) (control area). Texture analysis was performed evaluating 7 parameters: secondary angular momentum, contrast, correlation, sum of squares, inverse moment of difference, sum of entropies, and entropy. Data were analyzed using the Kruskal-Wallis test with a significance level of 5%. Results: Comparing the areas of AO, IT, and HT, significant differences (P<0.05) were observed. The IT and AO area images showed higher values for parameters such as contrast, entropy, and secondary angular momentum than the HT area, indicating greater disorder in these tissues. Conclusion: Through texture analysis, changes in the bone pattern could be observed in areas of osteonecrosis. The texture analysis demonstrated that areas visually identified and classified as IT still had necrotic tissue, thereby increasing the accuracy of delimiting the real extension of MRONJ.

• 구강회복응용과학지
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• 제27권4호
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• pp.359-370
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• 2011

임플란트의 골유착 성공 여부를 확인하기 위해서 방사선학적 분석방법을 사용하였다. 치근단 방사선 사진을 이용한 프렉탈 분석방법을 사용하여 기능하중 전 후의 임플란트 주변 골밀도를 분석하고 골유착에 실패한 임플란트와 성공한 임플란트 사이에 유의한 차이가 있는지 비교하였다. 본 연구에서는 원광대학교 치과병원에서 임플란트 식립 시술을 받은 30명의 환자에서 총 42개의 임플란트를 분석에 사용하였다. 환자는 14명의 남자와 16명의 여자로 구성 되었고 나이는 22세에서 73세 사이였다. 치조골의 trabecular 양상의 형태와 프렉탈 분석은 치근단 방사선 사진을 이용하였다. 총 2장의 치근단, 즉 임플란트 식립 직후와 임플란트 보철물 장착 후 기능 하중이 가해진 뒤 3개월 후의 방사선 사진이 사용되었다. 분석은 Image J(1.40s, National Institute of Health, Bethesda, USA)를 이용하여 시행하였다, 통계학적 분석방법은 one-way ANOVA(P<.05)를 이용하여 시행하였다. 그리고 Tukey multiple comparison test로 사후검정을 실시하였다. 프렉탈 분석 결과와 임플란트 주변의 골밀도 변화는 통계적으로 유의할만한 상관관계가 있으며 특히 하악에서 이런 결과가 더욱 명백하였다. 또한 두개의 실패한 임플란트의 경우 프렉탈 수치가 각각 1.2865에서 1.1521로, 1.1135에서 1.0478로 감소되는 경향을 나타냈다.

• 지질공학
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• 제19권4호
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• pp.459-474
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• 2009

암반의 불연속면과 선구조의 분포성을 상호 분석하고 대비한 결과 선구조선의 발달이 절리와 성인적으로 상관성이 있고, 시추코어를 대상으로 측정된 불연속면의 간격은 1~20 cm이며 단층작용과 관련된 단층각력을 함유하는 단열대가 발달하는 유문암체에서 절리간격이 가장 조밀하게 나타난다. $Nb/Y-Zr/TiO_2$ 성분도에서 본 역의 화산암류는 비알카리 계열의 응회암, 유문암, 현무암에 해당된다. Hf/3-Th-Nb/16 삼각도에 의하면 destructive plate-margin basalt와 이들의 분화물에 속하며 Rb/Zr-Nb 성분도에 의하면 화산암의 생성 환경은 normal continental arc에 해당된다. 대부분의 LREE가 아주 부화되고 HREE는 결핍되는 패턴을 보인다. K/Ar 방법으로 측정한 연대는 중성 화산암이 55.3 Ma, 응회암은 77.25~91.22 Ma, 유문암은 63.16~64.39 Ma, 결정질응회암은 54.49 Ma이다.

• 한국의류학회지
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• 제31권5호
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• pp.729-741
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• 2007

In order to examine the characteristics of brassiere products for the 1924 generation brands on the market and grasp problems, we selected three 'comparative brassieres', each one from among the 1924 underwear brands with the highest recognition and sales profit, and then designed a 'sample brassiere' pattern(75A) with a similar shape to the comparative brassieres. We set up the "New Cup Grading Rule" with a view of reflecting the wearing effect that was varied according to cup sizes, graded the sizes of 75AA and 75B with this method, and made the sample brassieres in three sizes. We conducted the wearing evaluation and body measurements of 9 subjects after analyzing the patterns and characteristics of the sample brassieres and three comparative brassieres. As a result of the wearing evaluation, the sample and comparative brassiere 2, the dimensions and shapes were appropriate for the 1924 generation consumers and expressed an overall natural silhouette, showed satisfactory results in the entire evaluation questions. On the other hand, the comparative brassiere 1 and 3 that tended toward making a big change in the physical characteristics got unsatisfactory evaluations in the dimensions of the cups, clothing pressure, and bust silhouette. As a result of observing the variation in body dimensions by body measurements when nude and when wearing each brassiere and then summing it up with the score of the wearing evaluation, it was proven that too much change in body shape can create a negative image by upsetting the balance of the whole silhouette. Therefore, it is desirable to develop brassiere products with proper dimensions and clothing pressure that can make a physical change that harmonizes the overall bust silhouette and the position and shape of the breasts.

• 비파괴검사학회지
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• 제14권2호
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• pp.101-111
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• 1994

전자처리스페클패턴간섭법을 CW 레이저에 비디오 시스템과 화상 처리 장치를 조합하여 평판의 변위를 측정하는데 이용하였다. 과거의 스트레인 게이지나 모아레법과는 달리 전자처리스페클패턴간섭법(ESPI)은 측정물에 아무런 처리를 할 필요가 없고, 완전한 비접촉 측정이 가능하며, 또한 감도가 높은 이점이 있다. 본 연구에서 사용한 시험편은 로드셀과 같은 방향으로 하중이 걸리도록 하였다. 시험편은 평판이고 스트레인 게이지를 부착하였다. 이 연구는 전자처리스페클패턴간섭법에 의해 변위와 응력 분포를 구하여 스트레인 게이지와의 비교함으로써 전자처리스페클패턴간섭법의 측정 정밀도에 대해 검토하고자 한다.

• Imaging Science in Dentistry
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• 제42권1호
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• pp.5-12
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• 2012

Purpose : This study was performed to evaluate possible variations in maxillary and mandibular bone texture of normal population using the fractal analysis, particles count, and area fraction in intraoral radiographs. Materials and Methods : Periapical radiographs of patients who had full mouth intraoral radiographs were collected. Regions of interest ($100{\times}100$ pixels) were located between the teeth of the maxillary anterior, premolar, and molar area, as well as the mandibular anterior, premolar, and molar areas. The fractal dimension (FD) was calculated by using the box counting method. The particle count (PC) and area fraction (AF) analyses were also performed. Results : There was no significant difference in the FD values among the different groups of age, gender, upper, and lower jaws. The mean FD value was $1.49{\pm}0.01$. The mean PC ranged from 44 to 54, and the mean AF ranged from 10.92 to 11.85. The values of FD, PC, and AF were significantly correlated with each other except for the upper molar area. Conclusion : According to the results, patients with normal trabecular pattern showed a FD of approximately 1.5. Based on these results, further investigation would be recommended if the FD value of patient significantly differenct from this number, since the alteration of this value indicates microstructural modification of trabecular pattern of the jaws. Additionally, with periapical radiographs, simple and cost-effective, PC and AF could be used to assess the deviation from the normal.

• Spatial Information Research
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• 제17권4호
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• pp.455-462
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• 2009

원격탐사 영상에서 압축을 위한 근최적의 PSNR 값을 찾는 방법을 연구하였다. 예상 웨이블릿쌍은 다양한 영상에서 최적의 결과로 나타났다. 영상처리를 위한 최고의 웨이블릿쌍을 찾는 규칙은 없다. 제시된 알고리즘에 따라 예상 웨이블릿쌍이 다양한 종류의 영상에서 최적의 결과를 나타냈다. 먼저 세 개의 웨이블릿 패밀리에서 PSNR 값의 변화를 분석하였다. 직교 웨이블릿 패밀리에서는 많은 경우에 웨이블릿 필터의 길이가 길수록 높은 PSNR 값을 나타내지만, 그 증가 비율이 점차로 작아졌다. 연산비용의 측면에서 중간 필터길이의 웨이블릿을 제안한다. 쌍직교 웨이블릿 패밀리에서는 필터의 길이와 PSNR값의 관계를 예측하기는 어려웠다. 다차원 웨이블릿 분석에서는 세 개의 웨이블릿 패밀리가 3단계까지 처리되었다. 쌍직교 웨이블릿 패밀리는 최대 PSNR 값에서 불규칙한 패턴을 보였지만, 직교 웨이블릿 패밀리는 규칙적 패턴을 나타냈다. 직교 웨이블릿 패밀리는 1단계 결과로부터 근최적의 웨이블릿쌍을 예상할 수 있었다.

• Journal of Periodontal and Implant Science
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• 제40권2호
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• pp.49-55
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• 2010

Purpose: The purpose of this study was to preliminarily evaluate the influence of diabetes mellitus (DM) on periodontal tissue without establishment of periodontitis. Methods: Seven-week-old db/db mice were used for the diabetic experimental group and systematically healthy mice of the same age were used as controls. After 1 week of acclimatization, the animals were sacrificed for hard and soft tissue evaluation. The pattern of bone destruction was evaluated by stereomicroscope evaluation with alizarin red staining and radiographic evaluation by microscopic computerized tomography images. Histological evaluation was performed with hematoxylin and eosin stain for evaluation of soft tissue changes. Results: In both stereomicroscope evaluation and radiograph image analysis, aggressive form of bone destruction was observed in diabetic animals when compared to the systematically healthy controls. In histological evaluation, apical migration of junctional epithelium with slight inflammatory cell infiltration was observed with disarrangement of connective tissue fibers. Conclusions: Within the limits of this study, diabetic animals presented distortion in periodontal attachment and an aggressive bone loss pattern when compared to the healthy controls, suggesting that DM has an independent effect on periodontal tissue destruction irrespective of the presence or absence of periodontal disease.