Günen Mehmet Akif, Atasever Umit Haluk
Department of Geomatics Engineering, Faculty of Engineering and Natural Sciences, Gümüşhane University, 29100 Gümüşhane, Turkiye.
Department of Geomatics Engineering, Faculty of Engineering, Erciyes University, 38039 Kayseri, Turkiye.
Sci Total Environ. 2024 May 20;926:172117. doi: 10.1016/j.scitotenv.2024.172117. Epub 2024 Mar 31.
Water resources are essential for the ecological system and the development of civilization. Water is imperative factor for health preservation and sustaining various human activities, including industrial production, agriculture, and daily life. Remote sensing provides a cost-effective and practical means to detect and monitor water bodies, offers valuable insights into the impact of climatic events on water structures, especially in coastal lake regions. The research primarily utilizes Landsat-9 OLI-2 satellite images to evaluate the effectiveness of various water indices (WRI, NWI, MNDWI, NDWI) in combination with global automatic thresholding methods (K-Means, Zhenzhou's, Adaptive, Intermodes, Prewitt and Mendelsohn's Minimum, Maximum Entropy, Median, Concavity, Percentile, Intermeans, Kittler and Illingworth's Minimum Error, Tsai's Moments, Otsu's, Huang's fuzzy, Triangle, Mean, IsoData, Li's). The study was carried out on Lake Nazik, Lake Iznik, and Lake Beyşehir, which have unique geographical characteristics, and examined the adaptability and robustness of the selected indices and thresholding methods. MNDWI consistently stands out as a robust index for water extraction, delivering accurate results across different thresholding methods in regions all three lakes. As a result of quite extensive analysis, it is obtained that MNDWI and NDWI are reliable choices for water feature extraction in various lake environments, but the specific index should consider the thresholding method and unique lake characteristics. The Minimum thresholding method stands out as the most effective thresholding technique, demonstrating impressive results across different lakes. Specifically, it achieved an average Peak Signal-to-Noise Ratio (PSNR) of 78.97 and Structural Similarity Index (SSIM) of 99.37 for Lake Nazik, 74.08 PSNR and 98.34 SSIM for Lake Iznik, and 63.96 PSNR and 93.61 SSIM for Lake Beyşehir.
水资源对生态系统和文明发展至关重要。水是养生和维持包括工业生产、农业及日常生活在内的各种人类活动的必要因素。遥感提供了一种经济高效且实用的手段来检测和监测水体，能深入了解气候事件对水体结构的影响，尤其是在沿海湖泊地区。该研究主要利用Landsat - 9 OLI - 2卫星图像，结合全局自动阈值法（K均值、郑州法、自适应法、双峰法、普雷维特和门德尔松最小值法、最大熵法、中值法、凹度法、百分位数法、均值法、基特勒和伊林沃思最小误差法、蔡氏矩法、大津法、黄氏模糊法、三角法、均值法、等组法、李氏法）评估各种水体指数（WRI、NWI、MNDWI、NDWI）的有效性。该研究在具有独特地理特征的纳齐克湖、伊兹尼克湖和贝伊谢希尔湖开展，考察所选指数和阈值法的适应性与稳健性。MNDWI始终是水体提取的稳健指数，在三个湖泊区域的不同阈值法下均能给出准确结果。经过广泛分析得出，MNDWI和NDWI是各种湖泊环境下水体特征提取的可靠选择，但具体指数应考虑阈值法和湖泊的独特特征。最小阈值法是最有效的阈值技术，在不同湖泊中均展现出令人印象深刻的结果。具体而言，它在纳齐克湖的平均峰值信噪比（PSNR）为78.97，结构相似性指数（SSIM）为99.37；在伊兹尼克湖的PSNR为74.08，SSIM为98.34；在贝伊谢希尔湖的PSNR为63.96，SSIM为93.61。
