Multi-oriented text detection for intra-frame in H.264/AVC video

Text detection in compressed video has received much attention in recent years due to the effectiveness of DCT coefficients and motion vectors in realizing several applications. In this paper, a new text detection, which utilizes AC coefficients in the H.264/AVC compressed video, is proposed. The proposed median deviation of coefficients from a specific subband is first computed, then the k-means clustering and morphological operations are applied to classify the text candidates. The majority orientation is considered to eliminate false positive candidate groups that have different orientations. Local block energy information is extracted to obtain the final text candidates. Experimental results show that the proposed method outperforms the existing methods either in computational time or accuracy in detecting horizontal text. Furthermore, for non-horizontal text, the proposed method is superior to all the conventional methods considered.