Traina Caetano, Traina Agma J M, Araújo Myrian R B, Bueno Josiane M, Chino Fabio J T, Razente Humberto, Azevedo-Marques Paulo M
Computer Science Department, University of São Paulo at Sdo Carlos, Brazil.
Comput Methods Programs Biomed. 2005 Dec;80 Suppl 1:S71-83. doi: 10.1016/s0169-2607(05)80008-2.
This paper presents a new Picture Archiving and Communication System (PACS), called cbPACS, which has content-based image retrieval capabilities. The cbPACS answers range and k-nearest- neighbor similarity queries, employing a relational database manager extended to support images. The images are compared through their features, which are extracted by an image-processing module and stored in the extended relational database. The database extensions were developed aiming at efficiently answering similarity queries by taking advantage of specialized indexing methods. The main concept supporting the extensions is the definition, inside the relational manager, of distance functions based on features extracted from the images. An extension to the SQL language enables the construction of an interpreter that intercepts the extended commands and translates them to standard SQL, allowing any relational database server to be used. By now, the system implemented works on features based on color distribution of the images through normalized histograms as well as metric histograms. Metric histograms are invariant regarding scale, translation and rotation of images and also to brightness transformations. The cbPACS is prepared to integrate new image features, based on texture and shape of the main objects in the image.
本文介绍了一种名为cbPACS的新型图像存档与通信系统（PACS），它具有基于内容的图像检索功能。cbPACS能够回答范围查询和k近邻相似性查询，采用了扩展以支持图像的关系数据库管理器。通过图像处理模块提取图像特征并存储在扩展关系数据库中，然后根据这些特征对图像进行比较。数据库扩展的开发旨在利用专门的索引方法高效地回答相似性查询。支持这些扩展的主要概念是在关系管理器内部基于从图像中提取的特征定义距离函数。SQL语言的扩展使得能够构建一个解释器，该解释器拦截扩展命令并将其转换为标准SQL，从而允许使用任何关系数据库服务器。目前，该系统基于归一化直方图以及度量直方图，根据图像的颜色分布来处理特征。度量直方图对于图像的缩放、平移和旋转以及亮度变换具有不变性。cbPACS准备好集成基于图像中主要对象的纹理和形状的新图像特征。
