page_dewarp.py 文件源码

def get_default_params(corners, ycoords, xcoords):

    # page width and height
    page_width = np.linalg.norm(corners[1] - corners[0])
    page_height = np.linalg.norm(corners[-1] - corners[0])
    rough_dims = (page_width, page_height)

    # our initial guess for the cubic has no slope
    cubic_slopes = [0.0, 0.0]

    # object points of flat page in 3D coordinates
    corners_object3d = np.array([
        [0, 0, 0],
        [page_width, 0, 0],
        [page_width, page_height, 0],
        [0, page_height, 0]])

    # estimate rotation and translation from four 2D-to-3D point
    # correspondences
    _, rvec, tvec = cv2.solvePnP(corners_object3d,
                                 corners, K, np.zeros(5))

    span_counts = [len(xc) for xc in xcoords]

    params = np.hstack((np.array(rvec).flatten(),
                        np.array(tvec).flatten(),
                        np.array(cubic_slopes).flatten(),
                        ycoords.flatten()) +
                       tuple(xcoords))

    return rough_dims, span_counts, params