Edging method used for SDI high-definition video character superimposition

The invention provides an edging method used for SDI high-definition video character superimposition. The method includes the step that in the video scanning process, edging operation is performed on a character dot matrix, and the edging operation comprises a horizontal edging process, a vertical edging process and an edging synthetic process. The horizontal edging process refers to performing left-right edging on characters in the display process of images and the characters from left to right. The vertical edging process refers to edging process perform top-bottom edging on the characters in the display process of the images and the characters from top to bottom. The edging synthetic process refers to performing image superimposition on character dot matrix and an edging dot matrix in the manner that the characters are on a top layer. After processing, complete edging on the characters is completed. By the adoption of the edging method, the characters can be superimposed on a high-definition video, and the content of the superimposed characters can be clearly displayed regardless of image backgrounds.