The extraction of center lines from light fringes is a crucial step in line-structure light measurement, as the extraction accuracy directly affects the measurement speed and precision. In response to the low extraction accuracy issue in traditional Steger algorithm due to large variations in light fringe width and excessive redundant points, an improved Steger-based fast and high-precision method for extracting center lines from light fringes is proposed in this paper. First of all, the original image of light fringes is preprocessed to remove noise points and retain the region of interest. Then, the width of light fringes is rapidly obtained by directly traversing pixel points, followed by Canny edge detection on the fringe area and calculation of pixel initial points using the geometric center method. Finally, a one-dimensional convolution is performed on the initial points to construct the Hessian matrix, enabling further precise extraction of the center line along the normal direction. Experimental results demonstrate that this algorithm improves accuracy by 42.6% compared to the traditional Steger algorithm and reduces processing time by 64.5%, thus achieving precise sub-pixel level extraction of light fringes while meeting the real-time requirements of industrial measurement.