@InProceedings{	  baeza.valiente:spire:2000,
  author	= {Ricardo Baeza-Yates and Gabriel Valiente},
  title		= {An Image Similarity Measure based on Graph Matching},
  booktitle	= {Proc.\ 7th Int.\ Symposium on String Processing and
		  Information Retrieval},
  year		= {2000},
  publisher	= {IEEE Computer Science Press},
  pages		= {28--38},
  abstract	= {The problem of computing the similarity between two images
		  is transformed to that of approximating the distance
		  between two extended region adjacency graphs, which are
		  extracted from the images in time and space linear in the
		  number of pixels. Invariance to translation and rotation is
		  thus achieved. Invariance to scaling is also achieved by
		  taking the relative size of regions into account.
		  Furthermore, the method provides a trade-off between pixel
		  similarity threshold and approximation of the distance
		  measure, which can be used to bound the error in image
		  recognition as well as the time complexity of the
		  computation.}
}