Hyperspectral Imagery for the Main Eight Hawaiian Islands:Oahu (210-0612-332211)

This project is a cooperative effort among the National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Monitoring and Assessment; the University of Hawaii; and Analytical Laboratories of Hawaii, LLC. The goal of the work was to develop coral reef mapping methods and compare benthic habitat maps generated by photointerpreting georeferenced color aerial photography, hyperspectral and IKONOS satellite imagery. The enhanced spectral resolution of hyperspectral and control of bandwidths of multispectral data yield an advantage over color aerial photography particularly when coral health and time series analysis of coral reef community structure are of interest. Depending on the type of instrument, a spectral imaging system can be utilized to see multiple colors from ultraviolet through the far infrared range. The AURORA hyperspectral imaging system collected 72 ten nm bands in the visible and near infrared spectral range with a 3 meter pixel resolution. The data was processed to select band widths, which optimized feature detection in shallow and deep water. Photointerpreters can accurately and reliably delineate boundaries of features in the imagery as they appear on the computer monitor using a software interface such as the Habitat Digitizer.

本项目由美国国家海洋服务局（National Ocean Service）、国家沿海海洋科学中心（National Centers for Coastal Ocean Science）、沿海监测与评估中心（Center for Coastal Monitoring and Assessment）、夏威夷大学以及夏威夷分析实验室有限责任公司（Analytical Laboratories of Hawaii, LLC）联合开展。本项目的研究目标为开发珊瑚礁制图方法，并对比通过解译地理参考彩色航空摄影、高光谱（hyperspectral）影像及IKONOS卫星影像生成的底栖生境（benthic habitat）地图。相较于彩色航空摄影，高光谱的增强光谱分辨率与多光谱（multispectral）数据的带宽调控能力具备显著优势，尤其在关注珊瑚健康状况与珊瑚礁群落结构的时间序列分析场景中优势尤为突出。根据仪器类型的差异，光谱成像系统可采集从紫外线到远红外波段范围内的多波段光谱信息。本研究采用的AURORA高光谱成像系统（AURORA hyperspectral imaging system）在可见光与近红外光谱范围内采集了72个10nm带宽的波段，像素分辨率为3米。研究团队对采集到的数据进行了波段带宽筛选优化，以实现浅水区与深水区的特征检测（feature detection）效果最优。借助栖息地数字化工具（Habitat Digitizer）等软件界面，影像解译员可在计算机显示器上精准且可靠地勾勒影像中各类地物的边界。