rectify.py 文件源码

def _solve_lr(vlines, w, l, opt_options=OPTIMIZATION_OPTIONS, opt_method=OPTIMIZATION_METHOD, limit=0.3):
    """ Solve for the left and right edge displacement.
    This routine estimates the amount to move the upper left and right cornders of the image
     in a horizontal direction in order to make the given lines parallel and vertical.

    :param vlines: Lines that we want to map to vertical lines.
    :param w:  The width of the image
    :param l:   The height of the image
    :param opt_options: Optimization options passed into `minimize`
    :param opt_method: The optimization method.
    :param limit:  A limit on the amount of displacement -- beyond this and we will assume failure.
    :return: (dl, dr),   the horizontal displacement of the left and right corners.
    """
    if len(vlines) == 0:
        return 0, 0

    a = np.append(vlines[:, 0, :], np.ones((len(vlines), 1)), axis=1)
    b = np.append(vlines[:, 1, :], np.ones((len(vlines), 1)), axis=1)

    def objective(x):
        dl, dr = x
        Hv = np.linalg.inv(H_v(dl, dr, w, l))
        return np.sum(np.abs(Hv[0, :].dot(a.T) / Hv[2, :].dot(a.T) - Hv[0, :].dot(b.T) / Hv[2, :].dot(b.T)))

    res = minimize(objective, (0., 0.),
                   options=opt_options,
                   method=opt_method)
    dl, dr = res.x

    # Give up if the solution is not plausible (this indicates that the 'vlines' are too noisy
    if abs(dl) > limit * w:
        dl = 0
    if abs(dr) > limit * w:
        dr = 0
    return dl, dr