swt.py 文件源码

def _create_derivative(cls, img):
        edges = cv2.Canny(img, 175, 320, apertureSize=3)
        # Create gradient map using Sobel
        sobelx64f = cv2.Sobel(img,cv2.CV_64F,1,0,ksize=-1)
        sobely64f = cv2.Sobel(img,cv2.CV_64F,0,1,ksize=-1)

        theta = np.arctan2(sobely64f, sobelx64f)
        if diagnostics:
            cv2.imwrite('edges.jpg',edges)
            cv2.imwrite('sobelx64f.jpg', np.absolute(sobelx64f))
            cv2.imwrite('sobely64f.jpg', np.absolute(sobely64f))
            # amplify theta for visual inspection
            theta_visible = (theta + np.pi)*255/(2*np.pi)
            cv2.imwrite('theta.jpg', theta_visible)
        return (edges, sobelx64f, sobely64f, theta)