A method for generating an ideal edge line is introduced in detail. In subpixel edge extraction algorithm

the accuracy of subpixel algorithm without noise and the ability of the algorithm to resist noise under noisy circumstance should be considered and examined separately. The ideal edge introduced in this paper can be used to examine the subpixel algorithm. Based on the principle of imaging formation of CCD camera and the square aperture sampling theorem

a calculation method of gray level of boundary points is given. Furthermore

calculation formulas of boundary points’ gray level are presented in a specific condition. It is convenient to generate an ideal edge using these formulas

which can be used in the validation of subpixel algorithm.