• 한국측량학회지
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• 제39권1호
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• pp.41-46
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• 2021

무인항공기를 이용한 데이터 취득이 널리 활용되면서 무인항공기를 이용한 사진측량의 정확도를 높일 수 있는 방안의 하나로 항공삼각측량의 번들 조정에 연직사진과 경사사진을 같이 사용하는 방법이 제시되고 있다. 본 연구에서는 사진측량의 정확도를 높이는 데 적합한 방법을 찾기 위해 촬영 각도를 달리하여 촬영한 경사사진을 조정하는 경우와 촬영 각도가 다른 경사사진을 연직사진과 동시에 조정하는 경우의 정확도를 비교하였다. 연구결과 입력되는 경사사진의 경사가 커질수록 검사점의 오차가 줄어드는 것으로 나타났으며, 특히 연직사진과 경사사진을 같이 사용할 때, 경사사진의 경사가 클수록 높이 오차가 크게 줄어드는 것으로 나타났다. 현행 『항공사진측량 작업규정』에서는 연직사진의 GSD (Ground Spatial Distance)와 동일한 RMSE (Root Mean Square Error)를 요구하고 있다. 촬영각도 50°의 경사사진을 이용할 때 이 기준에 거의 근접한 결과를 얻을 수 있었고, 연직사진과 50°의 경사사진을 동시에 조정한 경우 작업규정을 만족시킬 수 있었다. 본 연구 결과를 활용하면 무인항공기에 탑재된 저가의 사진기를 이용하는 사진측량이 더욱 활발해 질 수 있을 것으로 기대된다.

• 대한방사선기술학회지:방사선기술과학
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• 제44권5호
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• pp.443-449
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• 2021

In this study, the purpose is to present the foot inclination angle for realizing an image similar to that of the existing examination method and to present the clinical usefulness of the new examination method through comparison between the existing examination method and the newly designed standing foot oblique projection. A foot phantom was used, and the magnification of the image according to the angle was quantitatively evaluated by attaching a nut to the position of the cuboid of the phantom. The internal oblique image acquired using a 30° wedge was set as the standard image. And that image was compared with the images acquired by changing the angle of the foot from 20° to 65° at intervals of 5°. Image evaluation was performed by 3 radiological technologists, and qualitative evaluation using a Likert 5-point scale for evaluation items of true oblique view and quantitative evaluation of the value obtained by measuring the diameter of a nut in each image were performed as image evaluation. For data analysis, reliability analysis between the measure and comparative analysis of the average value for each angle were performed. The qualitative evaluation score for each image was 4.5 to 5 points for most questions in the case of the standard image. And 4 points or less for most questions in the images with a foot angle of 45° or less, and an evaluation score close to the standard image was obtained in the image of 50° or more. And in the quantitative evaluation, the diameter of the nut was measured to be 9.28~9.56 mm. The qualitative evaluation showed a reliability of 0.95~1.0 and the quantitative evaluation was 0.62. As a result of comparing and analyzing the average of the quantitative and qualitative average values for each angle image, the group with the average value most similar to the standard image was images obtained at 55° and 60°, and in the post-analysis, the images of both groups were the same group as the standard image(p<0.01). As a result of this study, it was found that the angle of inclination of the foot for realizing the image most similar to the existing image in the standing foot oblique projection is 55°~60°. In addition, if this test method is applied to the clinic, it is believed that it will help prevent safety accidents such as falls during the test and improve test efficiency by minimizing the movement of patients for the test.

• Investigative Magnetic Resonance Imaging
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• 제15권1호
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• pp.11-21
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• 2011

목적: 금속전극은 MRI 안에서 자기장의 왜곡을 일으켜 영상에 인공물이 나타난다. 본 논문에서는 전극이 B0와 수직으로 놓였을때 자기장 패턴의 특성을 이용하여 oblique-view angle imaging 방식을 통해 전극의 정확한 위치를 결정하는 방법을 제시하고자 한다. 대상 및 방법: 다양한 직경과 자화율을 가진 금속 전극모델의 시뮬레이션을 통하여 전극으로 인해 왜곡되는 field map의 양상을 파악하고 해상도에 따른 turbo spin-echo (TSE) 영상의 왜곡패턴을 분석하여 일반적인 영상기 법($90^{\circ}$ view)과 $45^{\circ}$ oblique-view에서의 위치 추정 기준을 마련하였으며 3.0T 임상용 장비에서 실제 전극의 TSE영상을 획득하여 시뮬레이션과 대조 검증하였다. 상대적으로 자기장의 왜곡에 민감한 gradient-refocused echo (GRE)시퀀스에서는 위상 영상을 이용해 위치를 추정하였다. 결과: 금속전극이 B0와 수직일 때 전극을 통과하는 $45^{\circ}$ 선상에서는 자기장 패턴의 변화가 매우 적었다. TSE 시퀀스의 경우 $45^{\circ}$ oblique-view 영상에서는 자화율의 크기에 관계없이 위치 추정기준이 잘 들어 맞았으며 자기장 왜곡에 의한 픽셀이 동양상이 양방향 대칭적으로 일어나므로 해상도가 낮은 경우에도 정확한 위치 추정이 가능하였다. 또한 GRE 시퀀스를 사용하였을때 $45^{\circ}$ oblique-view에서는 위상의 극성이 변화하는 선이 직교좌표계와 일치하기 때문에 일반적 방법보다 위치추정이 용이하였다. 결론: 시뮬레이션과 실제영상을 이용하여 일반적인 $90^{\circ}$ view에서보다 $45^{\circ}$ oblique-view에서 금속전극의 위치추정이 용이함을 확인하였다. 이는 전기 생리학적인 뇌연구 및 뇌수술 등을 MRI로 모니터링 하는데 적용 가능할 것으로 기대된다.

• 대한물리치료과학회지
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• 제25권3호
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• pp.25-31
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• 2018

Background: The purpose of this study was to find out how changes in knee angles in stable and unstable support surfaces affect the muscle thickness of core muscles. Methods: The subjects of this study were 25 male adult. Each knee angle of 120, 90 and 60 degrees, they were performed bridge exercise on the stabilized surface and on the unstable support surface using TOGU, and measured the muscle thickness of the external and internal oblique muscle and the abdominal muscles through ultrasound images. Results: There was no significant difference between the thickness of the rectus abdominis and the internal oblique muscle depending on the support surface and the knee joint bending angles. However, there was a significant difference between the external oblique muscle and the transverse abdominis muscle by knee joint flexion angle. Conclusion: While the muscle thickness of the core muscle was not significantly affected by each support surface during the bridge exercise, there were significant changes in the core muscle as a result of changes in knee angle.

• 대한족부족관절학회지
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• 제18권1호
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• pp.19-23
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• 2014

Purpose: The purpose of this study is to evaluate the clinical and radiographic results of symptomatic bunionette treated with a diaphyseal oblique osteotomy. Materials and Methods: We retrospectively reviewed 12 feet of nine patients diagnosed as symptomatic bunionette and treated with diaphyseal oblique osteotomy. All patients were female and the average age at the time of surgery was 48 years. We checked the foot standing anteroposterior, oblique, and lateral images pre- and post-operatively. We measured the fourth intermetatarsal angle and fifth metatarsophalangeal angle and evaluated the clinical results using the American Orthopaedic Foot and Ankle Society (AOFAS) lesser metatarsophalangeal-interphalangeal (MTP-IP) scale preoperatively and six months postoperatively. Results: Of the nine patients, hallux valgus was combined with symptomatic bunionette in seven feet of five patients. In all of our cases, the average AOFAS lesser MTP-IP scale showed improvement after surgery. Painful callosity around the fifth metatarsophalangeal joint disappeared after surgery in all of our cases. The fourth intermetatarsal angle improved from $12.7^{\circ}$ to $3.1^{\circ}$ and the fifth metatarsophalangeal angle improved from $16.6^{\circ}$ to $2.3^{\circ}$. Conclusion: Diaphyseal oblique osteotomy of the fifth metatarsal appears to be a safe and satisfactory surgical procedure for treatment of symptomatic bunionette.

• 한국방사선학회논문지
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• 제12권4호
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• pp.525-532
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• 2018

본 연구는 늑골의 사방향 검사 시 환자의 자세 변화가 아닌 X-선관의 수평 축방향 각도 변화를 적용하여 영상화 하였다. 인체 모형 팬텀을 이용하여 일반적인 늑골 사방향의 표준 검사 방법을 적용한 대조 영상과 중심 X-선을 팬텀의 수직 입사 방향으로부터 오른쪽 수평 축 방향으로 $5^{\circ}$ 간격으로 $5^{\circ}$부터 $30^{\circ}$까지 6단계의 입사각도 변화를 적용한 변형 사방향 실험 영상을 획득하였다. 영상의 정량적 비교 평가를 위해 대조영상을 기준으로 실험 영상의 관심 영역 별 SNR과 CNR을 계산하였다. 또한 대조 영상의 좌 우 늑골 비율과 실험 영상의 X-선 입사각도 별 좌 우 늑골 비율을 측정하여 비교하였다. 실험 결과, $25^{\circ}$의 X-선 입사 각도를 적용한 실험 영상이 표준 검사 방법을 적용한 대조 영상과 비교하였을 때 SNR과 CNR, 좌 우 늑골 비율의 측정값에서 가장 근사한 값을 나타내었다. 변형 늑골 사방향 검사는 환자의 검사 자세 유지가 어려울 경우 적용할 수 있는 늑골 사방향 검사 방법으로 유용할 것이라 생각된다.

• 한국측량학회지
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• 제36권3호
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• pp.117-126
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• 2018

Due to intelligent transport systems, location-based applications, and augmented reality, demand for image maps and 3D (Three-Dimensional) maps is increasing. As a result, data acquisition using UAV (Unmanned Aerial Vehicles) has flourished in recent years. However, even though orthophoto map production and research using UAVs are flourishing, few studies on 3D modeling have been conducted. In this study, orthophoto and 3D modeling research was performed using various angle images acquired by a UAV. For orthophotos, accuracy was evaluated using a GPS (Global Positioning System) survey that employed VRS (Virtual Reference Station) acquired checkpoints. 3D modeling was evaluated by calculating the RMSE (Root Mean Square Error) of the difference between the outline height values of buildings obtained from the GPS survey to the corresponding 3D modeling height values. The orthophotos satisfied the acceptable accuracy of NGII (National Geographic Information Institute) for a 1/500 scale map from all angles. In the case of 3D modeling, models based on images taken at 45 degrees revealed better accuracy of building outlines than models based on images taken at 30, 60, or 75 degrees. To summarize, it was shown that for orthophotos, the accuracy for 1/500 maps was satisfied at all angles; for 3D modeling, images taken at 45 degrees produced the most accurate models.

• Journal of Biosystems Engineering
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• 제22권3호
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• pp.295-302
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• 1997

An ultimate purpose of this study was to develop an automatic system for brown rice quality inspection using image processing technique. In this study emphasis was put on developing an algorithm for discriminating the brown rice kernels depending on their external quality with a color image processing system equipped with an adaptor magnifying the input image and optical fiber for oblique lightening. Primarily, geometical and optical features of images were analyzed with paddy and the various brown rice kernel samples such as a sound, cracked, peen-transparent, green-opaque, colored, white-opaque and brokens. Secondary, geometrical and optical parameters significant for identifying each rice kernels were screened by a statistical analysis(STEPWISE and DISCRIM procedure, SAS wer. 6) and an algorithm fur on- line discrimination of the rice kernels in static state were developed, and finally its performance was evaluated. The results are summarized as follows. 1) It was ascertained that the cracked kernels can be detected when e incident angle of the oblique light is less than 2$0^{\circ}C$ but detectivity was significantly affected by the angle between the direction of the oblique light and the longitudinal axis of the rice kernel and also by the location of the embryo with respect to the oblique light. 2) The most significant Parameters which can discriminate brown rice kernels are area, length and R, B and r values among the several geometrical and optical parameters. 3) Discrimination accuracies of the algorithm were ranged from 90% to 96% for a sound, cracked, colored, broken and unhulled, about 81 % for green-transparent and white-opaque and 75 % for green-opaque, respectively.

• 대한기계학회논문집B
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• 제36권3호
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• pp.351-361
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• 2012

슬관절 내반슬과 외반슬의 부정정렬을 교정하는 방법 중 대표적인 수술법이 근위경골절골술이다. 개방형 쐐기 근위경골절골술(OWHTO)의 경우 근위비골 인접부의 경골외측 비골신경을 손상시킬 우려가 없고, 수술도중 교정각의 개방 정도를 임의대로 조절 변경 가능한 장점으로 최근 선호되고 있다. 그러나 술후 관상면에서의 외반 및 내반 교정은 바르게 이루어지는 반면, 시상면에서는 수술자가 의도하지 않은 경골내측고평부의 후방경사각(PSA) 변화가 발생한다는 문제점이 있다. 저자들은 이와 같은 문제의 극복을 위해 Computer Assisted Surgery를 이용한 근위경골절골술 기법을 자체적으로 개발하였고, 근위경골부의 CT 이미지 3차원 재건과 컴퓨터를 이용한 가상절골술을 수행하였다. 또한 술후에도 후방경사각(PSA)이 변화하지 않는 수술기법에 대해 제시하였다. 본 연구결과는 환자고유의 전내측피질골 경사각(ACOA)과 후방경사각(PSA)의 명확한 관계성에 대해 제시해줄 것이며 환자마다 다른 최적의 후방경사각 결정법에 대해 제시해 줄 것으로 판단된다.

• 치과방사선
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• 제22권1호
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• pp.97-108
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• 1992

The author obtained 120 oblique-lateral transcranial radiograms by two projection methods from 30 subjects with clinically normal TMJ. The relative position of the condyle within the articular fossa and the quality of the radiographic images were compared in the standardized and individualized radiographic groups. The results were as follows: 1. The condylar position in the individualized radiographic group was more posterior than that in the standardized radiographic group (P<0.001). 2. The horizontal angle between the long axis of condyle and intermeatal line in the individualized group ranged from 0° to 31° (14.38°±7.55°), and the highest prevalence was found between 15 and 19° 3. The individualized group showed prominent radiopaque shadow of the anterior condylar border; the image detail was superior in the standardized group to that of the individualized group (P<0.05).