Abstract: An improved Sobel edge detection algorithm has been proposed to obtain the real-time edge of image data quickly with sharper edge and higher sensitivity.After applying the smoothing filter to the edge of the original image,two 3×3 templates are used to perform convolution on the data of the same size region in the selected two-dimensional image.The gradient values of this region can be obtained by combining the horizontal and vertical direction derivatives.Then,the gradient direction module is used to help judging the four directions of this region and defining the edge.The image edge is finally determined by non-maxima suppression and binarization.The improved Sobel edge detection algorithm is realized based on the FPGA and proved to be effective.