Text in video is a very compact and accurate clue for video indexing and summarization. But video texts are usually embedded in complex background

making it very difficultl for text separation from the background information. Hence the OCR accuracy was poor. This paper presents a multi frames based technique to enhance video text image. After extracting a reference text block

we use Hausdorff distance based image matching technique to find and register the corresponding text block. Then the frames average or minimum pixel search method is applied to text blocks to obtain a new text block with a clean background. At last we apply a finite interpolation function to adjust the text block resolution. Experiments conducted on several video sequences show that our enhancement scheme can considerably improve the accuracy of OCR.