Improved Algorithm about Subpixel Edge Detection Based on Zernike Moments and Three-Grayscale Pattern

The principle of Zernike moments and the method of sub-pixel edge detection based on Zernike moments were introduced in this paper. With the consideration of the limitation of the subpixel edge detection algorithm by Ghosal, such as the lower location precision of the edge and the extracted wider edge than that of the original image, an improved algorithm was proposed. A new pattern with three-grayscale for edge detection was put forward to detect the edge calculating masks of size seven multiply seven to get difference order Zernike moments. Additionally, experiments were designed and implemented. The experiment results show that accuracy of the improved algorithm is higher than that obtained from using Ghosal algorithm.