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Assessment of maize water status using a consumer-grade camera and thermal imagery

WATER SUPPLY 2021年第6期21卷 2543-2552页

作者： Mousabeygi, Fatemeh Rezaei, Yousef Akhavan, Samira Bu Ali Sina Univ Fac Agr Dept Water Engn Hamadan Hamadan Iran Bu Ali Sina Univ Fac Engn Dept Civil Engn POB 65178-33131 Hamadan Hamadan Iran

The analysis of plant response to water deficits can help us to identify appropriate water-saving and irrigation methods. The goal of this study is to assess the potential of eight indices derived from a modified consumer-grade camera and a thermal camera for monitoring the relative water content (RWC) of maize. The study design was a randomized complete block design with three replications and 16 treatments with four levels of irrigation water percentage based on field capacity (100% Fc, 80% Fc, 60% Fc and 40% Fc), and four levels of nitrogen (without nitrogen, 100 kg N/ha, 200 kg N/ha and 300 kg N/ha) were used. RWC values were used to evaluate the performance of the eight crop water stress indicators. The results showed that the best performance results of the studied vegetation indices were DANS, CTSD and CTCV, respectively. As observed, R-2 values were 0.88, 0.76 and 0.67, respectively.

关键词： maize modified camera otsu algorithm red-green ratio index relative water content

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Extraction and spatiotemporal changes of open-pit mines during 1985-2020 using Google Earth Engine: A case study of Qingzhou City, Shandong Province, China

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ENVIRONMENTAL MONITORING AND ASSESSMENT 2023年第1期195卷 209-209页

作者： Liu, Ruifeng Yuan, Kai Li, Xing Liu, Xiaoli Zhao, Xitao Guo, Xiaocheng Fu, Juan Cao, Shixin Shandong Prov Terr Ecol Restorat Ctr Jinan 250014 Peoples R China Jiangsu Normal Univ Sch Geog Geomat & Planning Xuzhou 221116 Peoples R China Qingzhou Nat Resources & Planning Bur Qingzhou 262500 Peoples R China

The global use of mineral resources has increased exponentially for decades and will continue to grow for the foreseeable future, resulting in increasingly negative impacts on the surrounding environment. However, to date, there are a lack of historical and current spatial extent datasets with high accuracy for mining areas in many parts of the world, which has hindered a more comprehensive understanding of the environmental impacts of mining. Using the Google Earth Engine cloud platform and the Landsat normalized difference vegetation index (NDVI) datasets, the spatial extent data of open-pit mining areas for eight years (1985, 1990, 1995, 2000, 2005, 2010, 2015, and 2020) was extracted by the otsu algorithm. The limestone mining areas in Qingzhou, Shandong Province, China, was selected as a case study. The annual maximum NDVI was first derived from the Landsat NDVI datasets, and then the otsu algorithm was used to segment the annual maximum NDVI images to obtain the extent of the mining areas. Finally, the spatiotemporal characteristics of the mining areas in the study region were analyzed in reference to previous survey data. The results showed that the mining areas were primarily located in Shaozhuang Town, Wangfu Street and the northern part of Miaozi Town, and the proportion of mining areas within these three administrative areas has increased annually from 88% in 1985 to more than 98% in 2010. Moreover, the open-pit mining areas in Qingzhou gradually expanded from a scattered, point-like distribution to a large, contiguous distribution. From 1985 to 2020, the open-pit mining area expanded to more than 10 times its original size at a rate of 0.5 km(2)/year. In 2015, this area reached its maximum size of 19.7 km(2) and slightly decreased in 2020. Furthermore, the expansion of the mining areas in Qingzhou went through three stages: a slow growth period before 1995, a rapid expansion period from 1995 to 2005, and a shutdown and remediation period after 2005. A qu

关键词： Google Earth Engine otsu algorithm Landsat Normalized difference vegetation index (NDVI) Open-pit mining

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Application of improved otsu threshold segmentation algorithm in mobile phone screen defect detection

Application of improved Otsu threshold segmentation algorith...

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32nd Chinese Control And Decision Conference (CCDC)

作者： Liu Meiju Zhuang Rui Guo Xifeng Zhao Junrui Shenyang Jianzhu Univ Sch Informat & Control Engn Shenyang 110168 Peoples R China

ISBN: (数字)9781728158556

ISBN: (纸本)9781728158556

In the process of defect detection of mobile phone screens using traditional algorithms, small defects are easily overlooked and erroneously detected. Compared with other algorithms, the two-dimensional otsu segmentation algorithm adds neighborhood threshold information, which reduces the influence of noise on the detection results, but the detection speed is slow. The author proposes an improved 2D otsu fast defect segmentation algorithm. First, bilateral filter and wavelet denoising algorithms are used to remove more noise. Then, the combination of straight line intercept and Particle swarm optimization is used to improve the otsu algorithm to quickly and accurately segment the target and background. Finally, the author conducted an experiment to apply the algorithm in this paper and the traditional otsu algorithm to mobile phone screen detection, and compared the segmentation results. The results show that the improved algorithm in this paper optimizes the inspection accuracy, improves the segmentation efficiency, and reduces the running time.

关键词： Glass screen of mobile phone Segmentation defect otsu algorithm Intercept Particle swarm optimization

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Automatic Cloud Detection in Remote Sensing Imagery Using Saliency-Based Mixed Features

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2023年 61卷

作者： Wang, Mi Wang, Xinsheng Pi, Yingdong Ke, Shiyun Wuhan Univ State Key Lab Informat Engn SurveyingMapping & Rem Wuhan 430079 Peoples R China Wuhan Univ Sch Resource & Environm Sci Wuhan 430079 Peoples R China

Cloud detection plays an important role in remote sensing image quality evaluation, information acquisition, and analysis. For most optical satellites, the acquired multispectral bands include only three visible bands and one near-infrared (NIR) band. How to achieve fast and accurate cloud detection with this limited number of bands is a problem worth studying. In this article, a cloud detection algorithm (SMFCD) based on a saliency-based mixed feature map of images is proposed. This algorithm first calculates the saliency characteristics from the band mean and haze-optimized transformation (HOT) map. The transmission map obtained from dark channel prior theory is used to combine the mixed feature map for subsequent detection. The proposed algorithm generates the initial thick cloud mask using a segmentation method based on the otsu algorithm later. Guided filtering is then used to refine the cloud mask. The final cloud detection result is acquired through postprocessing. The algorithm is tested on six different datasets. It is shown that the algorithm can obtain good detection results for most images, with overall accuracies from 0.860 to 0.969 on these datasets. The average time consumption on these datasets reaches 4.4-42.1 s, and a fast version of the proposed algorithm reduces these times by about 50%. The proposed algorithm can be used for remote sensing image quality evaluation and subsequent application preprocessing with greater adaptability and flexibility than existing algorithms since it does not depend on specific satellite radiometric calibration coefficients.

关键词： Feature extraction Remote sensing Clouds Image segmentation Indexes Task analysis Satellite broadcasting Cloud detection guided filtering otsu algorithm satellite images visual saliency

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Extracting Golden Area from Image Based on otsu algorithm

Extracting Golden Area from Image Based on Otsu Algorithm

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China Academic Conference on Food Packaging

作者： Wu Ying Zhao Xiuping Jin Yang Xu Yang Beijing Inst Graph Commun Beijing Peoples R China Tianjin Univ Sci & Technol Tianjin Peoples R China

ISBN: (纸本)9783037859469

The paper suggested an algorithm to extract the golden region with tone change in an image as a printing plate information of metallic ink. It is based on HSV color space. A statistical hue range of golden color was used to separate the golden regions from the image, and otsu algorithm was applied to acquire the tone of golden regions. The golden target regions are acquired by multiplication pixel by pixel between processed H values and the processed S values. The experiments were carried out on various images with different textures and background characteristics, and the segmentation effect were compared and analyzed also. They showed that the suggested algorithm is suitable for both simple and complex texture area. The color difference between image's background and target influences the result of extraction, he large color difference is more suitable for segmentation.

关键词： otsu algorithm Threshold segmentation Golden color HSV

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Comparison of different MRI-based unsupervised segmentation algorithms in predicting sarcopenia

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EUROPEAN JOURNAL OF RADIOLOGY 2024年 181卷 111748-111748页

作者： Zuo, Huayan Wang, Qiyang Bi, Guoli Wang, Yijin Yang, Guang Zhang, Chengxiu Song, Yang Wu, Yunzhu Gong, Xiarong Bi, Qiu Kunming Univ Sci & Technol Peoples Hosp Yunnan Prov 1 Affiliated Hosp Dept MRI Kunming 650500 Yunnan Peoples R China Kunming Univ Sci & Technol Affiliated Hosp Yunnan Prov Spinal Cord Dis Clin Med Ctr Peoples Hosp Yunnan Prov 1Dept Orthoped SurgKey Kunming 650032 Yunnan Peoples R China Kunming Univ Sci & Technol Peoples Hosp Yunnan Prov 1 Affiliated Hosp Dept MRI 157 Jinbi Rd Kunming 650032 Yunnan Peoples R China East China Normal Univ Shanghai Key Lab Magnet Resonance Shanghai 200241 Peoples R China Siemens Healthineers MR Res Collaborat Shanghai 201318 Peoples R China Nanjing Univ Informat Sci & Technol Inst AI Med Sch Artificial Intelligence Nanjing 210044 Peoples R China

Purpose: To compare the performance of MRI-based Gaussian mixture model (GMM), K-means clustering, and otsu unsupervised algorithms in predicting sarcopenia and to develop a combined model by integrating clinical indicators. Methods: Retrospective analysis was conducted on clinical and lumbar MRI data from 118 patients diagnosed with sarcopenia and 222 patients without the sarcopenia. All patients were randomly divided into training and validation groups in a 7:3 ratio. Regions of interest (ROI), specifically the paravertebral muscles at the L3/4 intervertebral disc level, were delineated on axial T2-weighted images (T2WI). The Gaussian mixture model (GMM), K-means clustering, and otsu's thresholding algorithms were employed to automatically segment muscle and adipose tissues at both the cohort and case levels. Subsequently, the mean signal intensity, volumes, and percentages of these tissues were calculated and compared. Logistic regression analyses were conducted to construct models and identify independent predictors of sarcopenia. An combined model was developed by combining the optimal magnetic resonance imaging (MRI) model and clinical predictors. The performance of the constructed model was assessed using receiver operating characteristic (ROC) curve analysis. Results: Age, BMI, and serum albumin were identified as independent clinical predictors of sarcopenia. The cohort-level GMM demonstrated the best predictive performance both in the training group (AUC=0.840) and validation group (AUC=0.800), while the predictive performance of the other models was lower than that of the clinical model both in the training and validation groups. After combining the cohort-level GMM with the independent clinical predictors, the AUC of the training and validation groups increased to 0.871 and 0.867, respectively. Conclusion: The cohort-level GMM shows potential in predicting sarcopenia, and the incorporation of independent clinical predictors further increased the performa

关键词： Sarcopenia Magnetic resonance imaging Gaussian mixture model K-means clustering otsu algorithm

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Dynamic monitoring of surface water areas of nine plateau lakes in Yunnan Province using long time-series Landsat imagery based on the Google Earth Engine platform

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GEOCARTO INTERNATIONAL 2023年第1期38卷

作者： Lu, Lichen Sun, Huiling Yunnan Normal Univ Fac Geog Kunming Peoples R China Survey Affairs Ctr Nat Resources & Planning Yongzh Yongzhou Peoples R China

Lakes are sensitive to both climate change and human activities, especially in the Yungui Plateau zone. As the main supply of water sources, surface water has a significant impact on environment, ecological balance and socioeconomic development. However, it is unclear how the surface water areas (SWAs) of the nine Yunnan Plateau lakes (NYPLs) have changed over previous decades. In this study, the SWAs of the NYPLs were first extracted using the optimal water index (WI) based on Landsat remote sensing images and the Google Earth Engine (GEE). Then, a spatiotemporal variation analysis of the SWAs was carried out for the NYPLs from 1988 to 2021. Finally, the correlations between the SWA changes in each lake, climatic factors and human activities were analysed. We found that the total SWAs of the NYPL have remained stable over the past 30 years, reaching a maximum of 1,012.51 km(2) in 2000 and a minimum of 972.94 km(2) in 2015. From 1988 to 2015, the overall SWAs of the NYPLs fluctuated steadily within 1%. However, Lakes Qilu and Yilong shrunk significantly in 2015. Generally, the SWAs of the NYPLs during the rainy season were larger than during the dry season;however, there were some differences between each period. The seasonal change in the SWAs was approximately 10 km(2) in 1991, 1994, and 2003, but was relatively less in other years. Precipitation was a direct factor, whereas temperature and evaporation were indirect factors influencing the intra- and inter-annual SWAs of the NYPLs. The changes in the SWAs of the NYPLs were consistent with the precipitation trend and were negatively correlated with changes in temperature and evaporation. Evaporation had more of an influence on shallow lakes than on deep-water lakes. Human activities led to significant changes in individual lakes (such as lakes Dianchi, Yilong, and Qilu). The NYPLs had a spatially heterogeneous response to regional climate change caused by both global climate change and human activities. The results

关键词： Nine Plateau Lakes surface water areas water index otsu algorithm Google Earth Engine

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Research on image segmentation algorithm based on threshold 13

Research on image segmentation algorithm based on threshold

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13th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA)

作者： Song, Shaozhong Gao, Ting JiLin Engn Normal Univ Sch Informat Engn Changchun 130052 Peoples R China Jilin Business & Technol Coll Coll Engn Changchun Peoples R China

ISBN: (纸本)9781665438926

Image segmentation technique is to segment an image into non-overlapping parts with similar features. It is the premise of image feature extraction and target recognition. The accuracy of different segmentation methods has a great impact on feature extraction and recognition. In order to verify the effect of different segmentation methods, this paper uses histogram threshold segmentation method and otsu segmentation method to segment the same target image. The experimental results show that both methods can segment the target region and the background region, and the segmentation results of the otsu segmentation method is better than the histogram threshold segmentation method, and the segmentation quality of the otsu segmentation method is better.

关键词： image segmentation Threshold segmentation method Histograms otsu algorithm

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Multi-lead Data Extraction Method of ECG Waveform Based on Mobile Device Application

Multi-lead Data Extraction Method of ECG Waveform Based on M...

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International Symposium on Computer, Consumer and Control (IS3C)

作者： Chen, Jun-Ying Wang, Liang-Hung Fuzhou Univ Coll Phys & Informat Engn Dept Microelect Fuzhou Peoples R China

ISBN: (纸本)9781728193625

Based on its portability and immediacy, mobile device have evolved and led to many innovations in medical domains. For electrocardiograms, the quickest and most intuitive way to store them is to take digital pictures. However, there are distortion and noise interference in real scene photographs inevitably. In this paper, a method is proposed to transform the preliminary digital image achieved by camera into the binarized multi-lead ECG curve individually. The vertex searching algorithm is designed to determine the location of the target paper against an intricate background. The vertex coordinates automatically detected are used in reverse perspective transformation to correct geometric distortion A robust improved otsu algorithm is developed to separate foreground curve from background noise and grid. In order to divide the lead curve region, the template matching technology is introduced to the recognition and the region segmentation of each lead information. Finally, a complement operation on the broken curve is performed and the pure and integrated ECG curve which suffices 1-D digitalization is obtained. The entire algorithm can standardize ECG from different sources and solve the problem of region sharing caused by data encryption.

关键词： Electrocardiogram(EGG) Multi-lead Digital image Processing(DIP) Distortion correction otsu algorithm Data standardization

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Binarization Mechanism Evaluation for Water Ingress Detectability in Honeycomb Sandwich Structure Using Lock-In Thermography

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MATERIALS 2022年第6期15卷 2333-2333页

作者： Chung, Yoonjae Shrestha, Ranjit Lee, Seungju Kim, Wontae Kongju Natl Univ Ecosustainable Energy Res Inst 1223-24 Cheonan Daero Cheonan Si 31080 South Korea Kathmandu Univ Sch Engn Dept Mech Engn Kathmandu 45200 Nepal Kongju Natl Univ Dept Future Convergence Engn 1223-24 Cheonan Daero Cheonan Si 31080 South Korea Kongju Natl Univ Div Mech & Automot Engn 1223-24 Cheonan Daero Cheonan Si 31080 South Korea

The growing use of composite honeycomb structures in several industries including aircraft has demonstrated the need to develop effective and efficient non-destructive evaluation methods. In recent years, active thermography has attracted great interest as a reliable technology for non-destructive testing and evaluation of composite materials due to its advantages of non-contact, non-destructive, full-area coverage, high speed, qualitative, and quantitative testing. However, non-uniform heating, low spatial resolution, and ambient environmental noise make the detection and characterization of defects challenging. Therefore, in this study, lock-in thermography (LIT) was used to detect water ingress into an aircraft composite honeycomb sandwich structure, and the phase signals were binarized through the otsu algorithm. A square composite honeycomb with dimensions of 210 mm x 210 mm along with 16 different defective areas of various sizes in groups filled with water by 25%, 50%, 75%, and 100% of the cell volume was considered. The sample was excited at multiple modulation frequencies (i.e., 1 Hz to 0.01 Hz). The results were compared in terms of phase contrast and CNR according to the modulation frequency. In addition, the detectability was analyzed by comparing the number of pixels of water ingress in the binarized image and the theoretical calculation.

关键词： water ingress non-destructive testing (NDT) lock-in thermography (LIT) composites signal processing image processing otsu algorithm binarization contrast to noise ratio (CNR)

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