image.py 文件源码

def align_face_3(im, key_points):
    '''
    Align face image by affine transfromation. The transformation matrix is computed by 
    3 pairs of points

    input:
        im: input image
        key_points: [(xi, yi)], list of 21-key-point or 106-key-point

    output:
        im_out
    '''

    key_points = np.array(key_points, dtype = np.float32)
    dst_points = np.array([[70.745, 112.0], [108.237, 112.0], [89.4324, 153.514]], dtype = np.float32)
    dst_sz = (178, 218)

    src_points = np.zeros((3, 2), dtype = np.float32)

    if key_points.shape[0] == 21:
        src_points[0] = key_points[16]
        src_points[1] = key_points[17]
        src_points[2] = (key_points[19] + key_points[20]) / 2.0
    elif key_points[0] == 106:
        src_points[0] = key_points[104]
        src_points[1] = key_points[105]
        src_points[2] = (key_points[84] + key_points[90]) / 2.0
    else:
        raise Exception('invalid number of face keypoints')

    trans_mat = cv2.getAffineTransform(src_points, dst_points)

    im_out = cv2.warpAffine(im, trans_mat, dsize = dst_sz, borderMode = cv2.BORDER_REPLICATE)

    return im_out