Algorithms for Extracting Textual Characters in Color Video

In this chapter, we present a new robust algorithm for extracting text in digitized color video. The algorithm first computes the maximum gradient difference to detect potential text line segments from horizontal scan lines of the video. Potential text line segments are then expanded or combined with potential text line segments from adjacent scan lines to form text blocks, which are then subject to filtering and refinement. Color information is then used to more precisely locate text pixels within the detected text blocks. The robustness of the algorithm is demonstrated by using a variety of color images digitized from broadcast television for testing. The algorithm performs well on JPEG images and on images corrupted with different types of noise. For video scenes with complex and highly textured backgrounds, we developed a technique to reduce false detections by utilizing multiframe edge information, thus increasing the precision of the algorithm.