Shape-based image retrieval in botanical collections

Apart from the computer vision community, an always increasing number of scientific domains show a great interest for image analysis techniques. This interest is often guided by practical needs. As examples, we can cite all the medical imagery systems, the satellites images treatment and botanical databases. A common point of these applications is the large image collections that are generated and therefore require some automatic tools to help the scientists. These tools should allow clear structuration of the visual information and provide fast and accurate retrieval process. In the framework of the plant genes expression study we designed a content-based image retrieval (CBIR) system to assist botanists in their work. We propose a new contour-based shape descriptor that satisfies the constraints of this application (accuracy and real-time search). It is called Directional Fragment Histogram (DFH). This new descriptor has been evaluated and compared to several shape descriptors.