Mark E. Hoffman and Edward K. Wong,
Content-based image object retrieval by scale-space
representation of shapes,
In C.-C. Jay Kuo, Shih-Fu Chang and Sethuraman
Panchanathan eds., Multimedia Storage and Archiving Systems III (VV02),
Boston, Massachusetts, USA, Vol. 3527 of SPIE Proceedings, pp. 2-12, November 1998. (SPIE Symposium on Voice, Video and Data Communications)Vast amounts of inexpensive storage and cost-effective input devices have promoted a rapid increase in the amount of stored digital images and video. Retrieving desired images from image databases is a challenging problem, not easily solved by existing database methods. Shape is one popular feature used to automate retrieval of images by content. Example shape features include the Fourier descriptor for describing shape boundaries, and area or compactness for describing shape regions, among others. We present a new shape-representation method based on extracting an image surface ridge-line called the Most Prominent Ridge-Line (MRPL) in scale-space. The MPRL is extracted by minimizing the second spatial derivative orthogonal to the ridge-line direction. The scale of the MPRL point is proportional to the image object's width. Matching query and database MPRLs is shown to be an effective method for retrieving images based on shape. A unique feature of the proposed method is that the scale space dimension may be weighted to allow for any desired amount of shape details in image retrieval.