The Normalized Difference Vegetation Index (NDVI), one of the earliest remote sensing analytical products used to simplify the complexities of multi-spectral imagery, is now the most popular index used for vegetation assessment. This popularity and widespread use relate to how an NDVI can be calculated with any multispectral sensor with a visible and a near-IR band. Increasingly low costs and weights of multispectral sensors mean they can be mounted on satellite, aerial, and increasingly—Unmanned Aerial Systems (UAS). While studies have found that the NDVI is effective for expressing vegetation status and quantified vegetation attributes, its widespread use and popularity, especially in UAS applications, carry inherent risks of misuse with end users who received little to no remote sensing education. This article summarizes the progress of NDVI acquisition, highlights the areas of NDVI application, and addresses the critical problems and considerations in using NDVI. Detailed discussion mainly covers three aspects: atmospheric effect, saturation phenomenon, and sensor factors. The use of NDVI can be highly effective as long as its limitations and capabilities are understood. This consideration is particularly important to the UAS user community.

归一化植被指数（NDVI）是最早用于简化多光谱图像复杂性的遥感分析产品之一，现已成为用于植被评估的最受欢迎的指数。这种普及和广泛使用涉及如何使用具有可见和近红外波段的任何多光谱传感器来计算NDVI。多光谱传感器的成本越来越低，重量越来越轻，这意味着它们可以安装在卫星，空中以及越来越多的无人机系统（UAS）上。尽管研究发现NDVI可以有效地表达植被状况和量化的植被属性，但NDVI的广泛使用和普及（尤其是在UAS应用中）具有固有的滥用风险，使最终用户几乎没有接受过遥感教育。本文总结了NDVI的获取进展，重点介绍了NDVI的应用领域，并解决了使用NDVI时遇到的关键问题和注意事项。详细的讨论主要包括三个方面：大气效应，饱和现象和传感器因素。只要了解NDVI的局限性和功能，NDVI的使用就会非常有效。这种考虑对UAS用户社区特别重要。