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Seminar Details


Date 24-7-2009
Time 11:00
Room/Location DISI-Sala Conferenze 3 piano
Title A Laplacian Method for Text Extraction in Video
Speaker Dr. P. Shivakumara
Affiliation School of Computing National University of Singapore Computing Link - Singapore
Link https://www.disi.unige.it/index.php?eventsandseminars/seminars
Abstract In this talk, we propose a new and efficient method for video text extraction based on the Laplacian operator. The maximum gradient difference value is computed for each pixel in the Laplacian-filtered image. K-mean clustering is then used to classify all the pixels into two clusters: text and non text. For each candidate text region, the corresponding region in the Sobel edge map of the input image undergoes projection profile analysis to determine the boundary of text lines. Finally, we employ heuristics to eliminate false positives based on geometrical properties. This method works well for horizontal text lines in video images. However, it fails to handle non-horizontal text lines, which are quite common in scene images. Therefore, we make use of connected component and skeleton to extend the Laplacian method. Each candidate text region is classified as simple or complex depending on the number of end points and intersection points of its skeleton. Complex connected components, which contain multiple text lines of different directions, are then split into smaller simple components. Finally, we use new features such as principal axis, medial axis and straightness of the components to eliminate false positives. Experimental results show that the method works well for text lines of different contrast, fonts, directions and backgrounds.
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