Abstract: Tidal level information is important in hydrographic developed a ruler reticle check method using image processing.surveying and water area measuring domain. This paper by reading video sequence of ruler which is pegged in the water, arithmetic based on hough transform and harris Goner detection can calculate the tidal level. Water experiment in dicates that the method has advanced practicability.

Key words: Hough transform, Harris corner detection, Tidal level, Image processing