For the borehole image obtained by digital panoramic borehole camera system

a method for recognizing structural plane is described based on characteristic function. According to the sinusoidal shaped characteristics of borehole side-wall discontinuities in the image

the method adopts standard sine function as characteristic function. The recognition of borehole structural plane is realized by changing the function parameters to match the nearby pixel grey gradient distribution and by choosing the best matching sine curve as the characteristic curve of structure plane. The method ignores the traditional process of manual selecting characteristic points and fitting characteristic curve. It provides a practical and effective way for the automatic recognition of borehole structural planes in engineering application with good stability and high accuracy.