Image Copy Detection Based on DCT Ordinal and Block Median

Abstract

As for highly repetitive image of Internet, a new image algorithm combined with DCT and block median method is designed. As there is a certain correlation between low-frequency coefficient of DCT and image scaling, the sequence vector of DCT coefficients is introduced with block median method to make up the defect of DCT processing for multi-channel image supplied. Through the combination of DCT and block median method, the recall and precision of new algorithm is over 95%. New algorithm works well in image scaling, resists well against watermarking attack and is able to detect the copy of target image fast and accurately from a large scale image datasets.