Segmenting character regions in an image is very important because these characters contain clear clues of retrieving and browsing images from video/image databases efficiently and effectively. In this paper
We propose a method to locate character regions of video/image in DCT compressed domain directly. With the distinguishing characteristics of character's texture (such as horizontal lines
vertical lines
or slant lines in a character) that can be extracted directly in DCT compressed domain
the character regions are segmented from their backgrounds quickly
and the image noises rising during the processing period can be removed by morphological filter. With this method
the compressed bit streams
which are encoded by DCT based encoding algorithm such as JPEG
MPEG 1/2
etc.
can be processed directly to locate the character regions in image
just a very small amount of decoding is required (Huffman decoding only). So
the amount of data which want to process is smaller
the processing speed is faster and the demand of computer memory is less. The experimental results show that the correct localization rate of this algorithm is higher.