Abstract: The laser centerline extraction is an important step in the measurement of the ice cross sectional profile, and the extraction accuracy directly affects the accuracy of the measurement system. Especially the ice on the structural light transmission is serious, the center line extraction algorithm is put forward a higher requirement. A fast centerline extraction method based on frequency domain transform is proposed to extract the center line in the three-dimensional measurement of ice. First, the image is subjected to noise reduction based on the technique of Block-matching and 3D filtering. Second, in order to reduce the computational complexity, the visual significance of the image is calculated by using the quaternion Fourier transform of phase spectrum, and then extract the optical band's region. Third, obtain the gradient map and convert to the frequency domain space, according to the image spectrum characteristics, we can obtain the center line position. The experimental results show that the algorithm is 28.57FPS, and the accuracy of ice contour reconstruction is 0.017mm.