Sub-pixel edge detection in the application of the deformation measurement technique

I come up with an improved algorithm of sub-pixel edge detection based on interpolation method. Traditional edge detection algorithm can only coarse position the edge points. In order to improve the accuracy and speed of edge detection, First of all, utilize the improved canny edge detection algorithm, by which to make the edge points reach its pixel level precision of the position and edge direction. Then, to extend pixels along the direction of the edge points, get the pixel gray value vector. By taking advantage of sub-pixel edge detection algorithm based on interpolation method, get the exact location of the edge points, so as to achieve sub-pixel edge location. As a result, I can achieve the high precision of material deformation measurement.