We propose an image duplicate detection method for identifying modified copies of the same image in a very large database. Modifications that we consider include rotation, scaling and cropping. A compact 12 dimensional descriptor based on Fourier Mellin Transform is introduced. The compactness of this descriptor allows efficient indexing over the entire database. Results are presented on a 10 million image database that demonstrates the effectiveness and the efficiency of this descriptor. In addition, we also propose extension to arbitrary shape repre- sentations and similar scene detection and preliminary results are also included.