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드론 다중분광영상과 컴퓨터 비전 기술을 이용한 배추 객체 탐지 알고리즘 개발
류재현,한중곤,안호용,나상일,이병모,이경도,Ryu, Jae-Hyun,Han, Jung-Gon,Ahn, Ho-yong,Na, Sang-Il,Lee, Byungmo,Lee, Kyung-do 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.5
농업분야에서 드론을 활용하여 작물의 생육을 진단하고 정보를 영상으로 제공하고 있다. 들녘 단위에 대한 고해상도 드론 영상을 활용하는 경우 객체별 생육정보를 생산할 수 있으나 정확하게 작물을 탐지하고 인접한 객체를 효율적으로 구분하기 위한 작업이 요구된다. 본 연구에서는 작물 객체를 탐지하고 위치 정보를 추출하는 알고리즘을 개발하는 것이 목적이다. 드론 다중분광영상과 컴퓨터 비전 기술을 활용하여 객체 탐지를 위한 알고리즘을 개발하였으며, 대상 작물은 가을배추로 선정하였다. 2018년~2020년까지 가을배추를 대상으로 정식 후 7일~15일 사이의 드론 영상을 취득하였으며, 2019년 영상 기반으로 객체 탐지 알고리즘을 개발한 뒤 2018년, 2020년 영상을 기반으로 알고리즘 평가를 수행하였다. 분광반사도 기반 지수와 식생의 분광반사도 특성을 고려하여 식생 지역을 추출하였다. 이후 추출된 식생 지역에서 객체의 크기를 고려하여 팽창(Dilatation), 침식(Erosion), 이미지 분할 등과 같은 모폴로지(Morphology) 기법을 통해 객체 탐지 정확도를 향상시켰다. 개발된 객체 탐지 알고리즘의 정밀도는 95.19% 이상이었으며, 재현율과 정확도는 각각 95.4%, 93.68% 이상이었다. 객체 탐지 알고리즘의 F1-Score는 0.967 이상으로 나타났다. 본 연구에서 개발한 알고리즘을 이용하여 추출된 배추 객체 중심에 대한 위치 정보는 작물의 재배시기에 따라 영농단계별 의사결정 정보를 제공하기 위한 자료로써 활용될 것이다. A drone is used to diagnose crop growth and to provide information through images in the agriculture field. In the case of using high spatial resolution drone images, growth information for each object can be produced. However, accurate object detection is required and adjacent objects should be efficiently classified. The purpose of this study is to develop a Chinese cabbage object detection algorithm using multispectral reflectance images observed from drone and computer vision techniques. Drone images were captured between 7 and 15 days after planting a Chinese cabbage from 2018 to 2020 years. The thresholds of object detection algorithm were set based on 2019 year, and the algorithm was evaluated based on images in 2018 and 2019 years. The vegetation area was classified using the characteristics of spectral reflectance. Then, morphology techniques such as dilatation, erosion, and image segmentation by considering the size of the object were applied to improve the object detection accuracy in the vegetation area. The precision of the developed object detection algorithm was over 95.19%, and the recall and accuracy were over 95.4% and 93.68%, respectively. The F1-Score of the algorithm was over 0.967 for 2 years. The location information about the center of the Chinese cabbage object extracted using the developed algorithm will be used as data to provide decision-making information during the growing season of crops.
드론 영상을 이용한 Sentinel-2, Landsat-8 위성 NDVI 평가: 벼 병해 발생 지역을 대상으로
류재현,안호용,나상일,이병모,이경도,Ryu, Jae-Hyun,Ahn, Ho-yong,Na, Sang-Il,Lee, Byungmo,Lee, Kyung-do 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6
The frequency of exposure of field crops to stress situations is increasing due to abnormal weather conditions. In South Korea, large-scale diseases in representative paddy rice cultivation area were happened. There are limits to field investigation on the crop damage due to large-scale. Satellite-based remote sensing techniques are useful for monitoring crops in cities and counties, but the sensitivity of vegetation index measured from satellite under abnormal growth of crop should be evaluated. The goal is to evaluate satellite-based normalized difference vegetation index (NDVI) retrieved from different spatial scales using drone imagery. In this study, Sentinel-2 and Landsat-8 satellites were used and they have spatial resolution of 10 and 30 m. Drone-based NDVI, which was resampled to the scale of satellite data, had correlation of 0.867-0.940 with Sentinel-2 NDVI and of 0.813-0.934 with Landsat-8 NDVI. When the effects of bias were minimized, Sentinel-2 NDVI had a normalized root mean square error of 0.2 to 2.8% less than that of the drone NDVI compared to Landsat-8 NDVI. In addition, Sentinel-2 NDVI had the constant error values regardless of diseases damage. On the other hand, Landsat-8 NDVI had different error values depending on degree of diseases. Considering the large error at the boundary of agricultural field, high spatial resolution data is more effective in monitoring crops.
유두상 갑상선 암 환자에서 수술 전 혈청 호중구-림프구 비의 임상적 의의
오행진,장여구,홍성우,이우용,이병모,HaengJin Ohe,Yeo Goo Chang,Seong Woo Hong,Woo Yong Lee,Byungmo Lee 대한갑상선-내분비외과학회 2014 The Koreran journal of Endocrine Surgery Vol.14 No.4
Purpose: Papillary thyroid cancer (PTC) is known to have a favorable prognosis and low mortality. However, some PTC has aggressive propensity with loco-regional recurrence or distant metastasis, and it could cause poor quality of life. Many studies for predicting high-risk group in papillary thyroid cancer have been reported, however, more study is needed. The objective of this study is to assess the efficiency of inflammation indices including the Neutrophil-Lymphocyte Ratio (NLR) as a predictor for high-risk group in papillary thyroid cancer patients. Methods: From January 2006 to November 2012, this study enrolled consecutive 164 patients who underwent total thyroidectomy and were confirmed with papillary thyroid cancer by histopathology. Among 164 patients, 23 were excluded because they had co-morbidities which could confound the inflammation related variables. We reviewed the medical records of 141 patients and assessed the correlation between inflammation indices including preoperative serum NLR and clinical prognostic parameters, including age at presentation, tumor size, extra-thyroidal extension, lymph node metastasis, TNM stage, and MACIS score. Results: In the papillary thyroid cancer patients, preoperative value of NLR, ESR, CRP, platelet, and albumin showed no significant correlation with the risk factors. Conclusion: In this study, preoperative inflammatory parameters such as NLR had uncertain efficacy as risk factors for papillary thyroid cancer.
홍성우 ( Seong Woo Hong ),장여구 ( Yeo Goo Chang ),이병모 ( Byungmo Lee ),이우용 ( Woo Yong Lee ) 대한소화기학회 2016 대한소화기학회지 Vol.68 No.3
Spontaneous bleeding from a short gastric artery in the absence of pre-disposing trauma is reported very rarely. To the best of our knowledge, the published literature includes only 14 cases. Young men comprise almost all of the patients, and were induced by vomiting or gagging. The patients usually required emergent surgery. Our patient, a 32-year-old man, was diagnosed with spontaneous hemoperitoneum due to short gastric artery tearing after a few instances of vomiting. We managed him conservatively including fluid, vitamin K and antifibrinolytic agent without surgery. (Korean J Gastroenterol 2016;68:152-155)