img_edge = cv2.Laplacian(img_blur, cv2.CV_8U, ksize=5)

This line of code applies the Laplacian operator to the input image, img_blur, to detect edges. The resulting image, img_edge, will contain the edges detected by the Laplacian operator. The second argument, cv2.CV_8U, specifies the data type of the output image, which is an 8-bit unsigned integer. The third argument, ksize=5, specifies the size of the Laplacian kernel, which determines the strength and sensitivity of the edge detection.