Flank angle measurement based on improved Sobel operator

Abstract A new method using the screw thread edge image characteristics was proposed. A new template named improved Sobel templates, which had 67.5°and 112.5°direction templates, was used to obtain the edge of image after the image pretreatment. Different weighted values of the inner pixels in the template were proposed depending on the different distance from every pixel in the template to the center point. Comparing the edge of angle threads with different tooth type in edge extraction processing using the improve Sobel and the traditional Sobel operators, the improved Sobel operator had advantages of clearer edges and better continuity.