FAST EXTRACTION OF EDGE HISTOGRAM IN DCT DOMAIN BASED ON MPEG-7

Due to the decoding procedure of JPEG image and filtering for edge detection, the feature extraction process of MPEG-7 Edge Histogram Descriptor (EHD) is time consuming as well as computationally expensive. To improve efficiency of compressed image retrieval, we propose a new edge histogram generation algorithm in DCT domain in this paper. Using edge information provided by the AC coefficients of DCT coefficients, we can get the direction and strength, which is utilized for the edge histogram generation, of the edge directly in DCT domain. The experimental results demonstrate that our system has good performance in terms of retrieval efficiency and effectiveness.