We manually divided 10,800 images from the Corel Photo Gallery  into 80 concept groups, e.g., autumn, aviation, bonsai, castle, cloud, dog, elephant, iceberg, primates, ship, stalactite, steam-engine, tiger, train, and waterfall. Figure 6 shows some example images. We reorganised the Corel Photo Gallery, because 1) many images with similar concepts were not in the same group and 2) some images with different semantic contents were in the same group in the original database. In the reorganised database, each group includes more than 100 images and the images in the group are category-homogeneous. These concept groups were used in the evaluation of the results of our algorithms [1-5].
1. W. Bian and D. Tao, “Biased Discriminant Euclidean Embedding for Content based Image Retrieval,” IEEE Transactions on Image Processing (TIP), accept with minor revision.
2. D. Tao, X. Li, and S. J. Maybank, “Negative Samples Analysis in Relevance Feedback,” IEEE Transactions on Knowledge and Data Engineering (TKDE), vol. 19, no. 4, pp. 568-580, April 2007.
3. D. Tao, X. Tang, X. Li, and X. Wu, “Asymmetric Bagging and Random Subspace for Support Vector Machines-based Relevance Feedback in Image Retrieval,” IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), vol. 28, no.7, pp. 1088-1099, July 2006.
4. J. Li, N. Allinsion, D. Tao, and X. Li, “Multitraining Support Vector Machine for Image Retrieval,” IEEE Transactions on Image Processing (TIP), vol. 15, no. 11, pp. 3597-3601, November 2006.
5. D. Tao, X. Tang, X. Li, and Y. Rui, “Kernel Direct Biased Discriminant Analysis: A New Content-based Image Retrieval Relevance Feedback Algorithm,” IEEE Transactions on Multimedia (TMM), vol. 8, no. 4, pp. 716-727, August 2006.
6. J. Z. Wang, J. Li, and G. Wiederhold, “SIMPLIcity: Semantics-Sensitive Integrated Matching for Picture Libraries,” IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), vol. 23, no. 9, pp. 947-963, September 2001.
** You can download the following files and use 7zip to obtain all labeled images, which have been used in the above publications.