基于Oracle的林业应用影像数据库设计方案探讨

Discussion on Design of Oracle-Based Image Library for Application to Forestry

在Oracle10g的GeoRaster模块支持下,提出对影像的物理存贮和影像数据库组织管理的可行方案,并针对在Oracle中建立影像的金字塔、实现影像的压缩、影像索引等方面说明了具体的实现办法。在影像数据库组织方面,提出2种组织模式无缝影像层模式和分幅影像层模式;在数据访问效率方面,通过建立影像数据金字塔和基于影像块建立R树空间索引来提高数据访问效率;在数据压缩方面,在遵循OracleGeoRaster架构的基础上,通过扩充GeoRaster的影像元数据来支持数据压缩存贮能力。基于该设计方案,成功实现了一个原型系统。

Remote sensing images are the important information,source in forestry system. Forestry researches are vast in territory,scene are large and data are huge. And generally it requires images at multiple resolutions from 1 to hundreds meters. So,it's crucial to make a solution which can show high performance in querying and processing,provide strong support on storing and managing the huge amount of multi-resolution and multi-band image data,and browsing in 3D view. To meet those demands,based on Oracle 10g GeoRaster component,the method of designing image library was discussed. The feasible scheme of images storage and organization of image library were put forward. In this study,the organizing method of image layers was divided into seamless image layer model and tiled image layer model. Different approach has been carried out for both models in building spatial indexing,i.e. building blocks index for seamless image layer model and tiles index for tiled image layer model,respectively. The PL/SQL codes of building pyramid for GeoRaster objects were listed. Zip and JPEG 2000 compression formats were applied to improve the performance of data extracting. Finally,a prototype system for the design solution was introduced.