Chapter 55 Sub-Pixel Water-Sky-Line Detection Based on a Curve Fitting Method

摘要

Celestial navigation is one essential means of the marine autonomous navigation, through taking photos of the Water-Sky-Line, natural horizontal plane can be provided for celestial navigation system, and the precision of Water-Sky-Line detection influences the precision of positioning. Traditional edge detection algorithms can only achieve pixel precision, as for more precise position of the Water-Sky-Line, those algorithms can't achieve. In order to achieve sub-pixel detection, first two processes on the original image are needed, including median filtering and resample, then the pixel sketch coordinates are detected by Kirsch operator, finally an algorithm based on a curve fitting method is introduced, and sub-pixel coordinates are detected. According to experimental analyses, it is effective to half of the pixels; after eliminating outliers, the precision is about 0.5 pixels.